Beta Moving Ashore Today Then Likely Tracking Slightly South of Houston

As of 10:00 a.m. Monday morning, the National Hurricane Center (NHC) still shows the center of Tropical Storm Beta located offshore. The latest forecasts from the NHC predict that Beta will move onshore near Matagorda Bay, then move up the coastline toward League City.

The NHC also advises that the storm has picked up speed. Yesterday, they estimated 3 mph; today 7 mph.

No one seems to predict that the storm will intensify before landfall.

“Dry air continues to work into and wrap around the large wind field of Beta yielding the disorganized precipitation field with the system.”

Jeff Lindner, Harris County Meteorologist
National Weather Service radar Image of Beta as of 10:04 am Monday 9/21/20.
Lake Houston Area is the blue dot in the center of the swirl. Red line is predicted path of Beta. Source: Weather Live.

Main Threat: Storm Surge

At this time, Beta’s main threat is to the coastline through storm surge. “Tides are currently running 4.0-4.5 feet in Clear Lake and across coastal sections of Harris County with several sites near the Gulf beaches running 4.0-4.5 feet. Coastal flooding is ongoing and will continue for much of the day. Several roadways are underwater along the coast and around Galveston Bay,” says Lindner.

Lindner continues, “As Beta makes landfall along the middle Texas coast later today, the storm will begin to slow and then turn ENE toward the upper TX coast. It will slowly weaken along the way. This track will keep onshore flow along the upper Texas coast tonight and Tuesday. Tides will remain high into the high tide tonight. Impacts along the coast will continue through the day and into tonight and likely Tuesday.”

Wind Forecast

The most likely arrival time of tropical storm force winds, if we get them, is later tonight.

Tropical storm force winds already cover a large part of the mid-Texas coast.

The storm will weaken as it moves toward the Houston Area and turn into a tropical depression. The further north you live from the coastline, the less intense winds will be.

Depending on where you live in Houston, you have a 30% to 100% chance of experiencing topical storm force winds. The Lake Houston Area is on the low end of that range. The National Weather Service predicts that the Lake Houston Area has a chance of seeing 39-57 mph winds. But Spaces City Weather advises that Beta is “not a significant wind threat.”

However, note that tropical-storm-force winds currently extend outward up to 175 miles (280 km) from the center of the storm.

Galveston has reported sustained winds of 39 mph and a gust of 43 mph during the past couple of hours.

Rainfall

Dry air has worked into the circulation of Beta, according to Lindner. “This has resulted in a more disorganized and scattered rainfall pattern. However, the system is still capable of heavy rainfall especially near the center later today and in bending structures east of the center for the next 48 hours.”

Models show several banding features developing during the next 48 hours over SE TX, But little consensus exists on where the heaviest rainfall totals may be.

Lindner advises that, “Given that much of the area will reside on the eastern side of a the tropical system, we should keep some level of concern of heavy rainfall and flooding in place through the next 48 hours.”

Lindner predicts that widespread rainfall amounts of 4-8 inches will be possible for areas along and south of I-10 with isolated totals of 10-12 inches under any training feeder bands. Totals to the north of I-10 will likely average 3-5 inches with isolated totals of 6-7 inches. 

However, the NHC predicts slightly less rain. See the map below.

As long as the rainfall spreads out over the next 48 hours, most of the creeks and bayous can handle the expected rainfall amounts, Lindner says. But should any training develop, flash flooding would be possible. 

Watches and Warnings in Effect

A Storm Surge Warning is in effect for Port Aransas, Texas to Rockefeller Wildlife Refuge, Louisiana. That includes Copano Bay, Aransas Bay, San Antonio Bay, Matagorda Bay, Galveston Bay, Sabine Lake, and Lake Calcasieu.

A Tropical Storm Warning is in effect for Port Aransas Texas to Morgan City Louisiana. That includes the Lake Houston Area.

National Hurricane Center

A TROPICAL STORM WARNING MEANS THAT TROPICAL STORM CONDITIONS ARE EXPECTED SOMEWHERE WITHIN THE WARNING AREA WITHIN 36 HOURS.

Lindner, the NHC and NWS all warn that tornadoes remain a threat with this storm. Especially, tonight and Tuesday.

Track

Yesterday, models predicted that Beta would track up US59 toward the Humble/Kingwood Area. However, today, forecasters think the storm will track closer to the coast. They put it on a line toward League City.

Wind shear will keep Beta’s track close to the coastline, but it will also affect the cyclone’s intensity along with land interaction. The closer the cyclone stays near the Gulf of Mexico, the more likely that bands of convection containing tropical-storm-force winds will continue to roll onshore the Texas coast through 36-48 hours.

Summary

Flash, urban, and isolated minor river flooding is possible, but the danger is “slight.”

National Hurricane Center

Net: Beta is still a threat. But it may be less of one than yesterday. That’s because of the dry air folding into the system and wind sheer which seem to be weakening it somewhat. Be hopeful, but cautious. Expect several inches of rain and high winds in the next two days with both tapering off Wednesday.

Posted by Bob Rehak on 9/21/2020 at noon based on data from NHC, NWS, Jeff Lindner, Space City Weather and Weather Live

1119 Days after Hurricane Harvey and 368 since Imelda

Excessive Rainfall Threat from Beta Spreads Inland

As of mid-day Sunday, all of East Texas now faces some level of excessive rainfall and flash flood risk from Tropical Storm Beta.

The projected path of the storm has shifted inland, so rainfall will reach father north. The latest track now takes the storm on a path right up US59 from Sugar Land to Humble and Kingwood. However, Beta likely be a tropical depression by the time it reaches the north side.

Kingwood is the blue dot next to Spring.

Six to 15 Inches of Rain Now Predicted

According to the local National Weather Service office and the National Hurricane Center, most of the Houston region can expect 6 to 15 inches with the highest totals closer to the coast.

Harris, Montgomery and Liberty Counties (and the whole Houston region) face a high to moderate threat of flooding rains. The first rainbands from Beta have already started to move onshore today, but the heaviest rain will not occur until Monday into Tuesday.

North Houston Under Moderate Flooding Rain Threat

Flash Flood Watch in Effect

The entire region is under a flash flood watch. Coastal areas also face storm surge and tropical storm warnings.

Slow Moving Storm Will Produce Prolonged Rains

Beta is meandering slowly at about 3 mph northwest toward the coastline west of Houston and will then curl back over Houston. It should move inland sometime Monday or Monday night and turn from a storm into a depression by the time it reaches Houston.

However, Beta could dump rain on us from later today all the way through Wednesday.

40-50% Chance of Tropical Storm Force Winds Reaching North Houston

The North Houston Area has a 40-50% chance of seeing tropical storm force winds from Beta.

If the high winds reach this far inland, they would likely arrive Monday evening. Winds extend outward from the center for 195 miles as of Sunday morning.

Feeder Bands Extend Outward 190 Miles

In fact, at 11 a.m. Sunday morning, the first feeder band was approaching the eastern side of Houston, as you can see in the radar image below.

This image shows how the wind and rain from Beta could remain with us for days as the storm’s center wanders around the Gulf.

These feeder bands reach out 190 miles. That is roughly the distance from Houston to San Antonio. So Beta will produce long-duration rainfall from the middle Texas coast to southern Louisiana. 

Flash, Urban, and River Flooding Likely 

The National Weather Service warns that coastal flooding will remain a threat through midweek with the worst of the storm surge anticipated on Monday and Tuesday. 

Elsewhere impacts from the excessive rain include:

  • Rainfall flooding may prompt evacuations and rescues.
  • Rivers and tributaries may rapidly overflow their banks.
  • Small streams, creeks, canals, and ditches may become dangerous rivers.
  • Flood control systems and barriers may become stressed. 
  • Flood waters may cover escape routes. 
  • Streets and parking lots may become rivers of moving water with underpasses submerged.
  • Driving conditions may become dangerous. 
  • Many roads and bridges may close with some weakened or washed out.

Lake-Level Situation

According to the SJRA, Beta has the potential to dump up to 8 inches of rain in Montgomery County. 

SJRA is operating under standard protocols for a severe weather event and will be onsite at Lake Conroe throughout the duration of Tropical Storm Beta.  

Lake Conroe remains 18 inches low, and based on the current forecast, no reservoir releases are expected. 

SJRA

Real-time information on lake level can be found on the SJRA homepage at the “Lake Operations and Rainfall Dashboard” link.

At of this writing, Lake Houston is down a foot compared to its normal pool level (41.38 vs 42.4). You can monitor Lake Houston levels via the Coastal Water Authority website.

Monitor Downstream River Levels

You can monitor stream and river levels in near-real time at Harris County Flood Warning System. Make sure you check out the inundation mapping feature.

Posted by Bob Rehak on 9/20/2020 based on information from the National Weather Service and National Hurricane Center

1118 Days after Hurricane Harvey

How Much Rain Would It Take To Flood Elm Grove Again?

As Tropical Storm Beta bears down on the Houston Area, many people in the Elm Grove/North Kingwood Forest area worry that they might flood again. How likely is that, given the current predictions of 6-10 inches? After all, on May 7 last year, Elm Grove flooded on what was officially a six inch rain according to the nearest gage at West Lake Houston Parkway and the West Fork.

Additional Detention in Woodridge Village Now…

First of all, understand that upstream conditions have changed. On May 7th, only about 11% of the planned detention pond capacity had been constructed. And only 23% was constructed by Imelda. Today, 100% is in place.

…But Detention Based on Pre-Atlas 14 Rainfall Rates

Even though that’s far more than Woodridge Village had during the May or September floods, the detention calculations by LJA Engineering were based on pre-Atlas 14 rainfall rates. A 100-year rainfall then was about 40% less than the official 100-year rainfall now.

So, the questions is, “How much rain would Beta have to dump on Woodridge Village before it overwhelmed the detention ponds that exist today?”

Figures Used by LJA

The chart below shows the rainfalls that the ponds were designed to hold without flooding. The bench mark its the 24-hour, hundred year rain.

These figures come from the hydrology report submitted by LJA to Montgomery County. A table buried on page 32 of the PDF shows that they based their analysis on a pre-Atlas 14, 100-year storm that dropped 12.17 inches of rain in 24 hours.

From Page 2.1 of LJA Hydrology Report Addendum, 8/28/2018 (page 32 of pdf.)

The ponds should also hold any of the shorter-duration rainfalls in the last column above.

Assumptions Underlying the Answer

To answer the question – How much would it take to flood Elm Grove again? – we need to make several assumptions:

With those caveats in mind, it would take 12+ inches of rain in 24 hours to exceed the capacity of the detention ponds currently on Woodridge Village. After that, water would start to overflow.

Short, High-Intensity Downpours Can Cause Different Type of Flooding

However, consider the other durations in the chart above. Seven inches in three hours or nine inches in six hours could also exceed the capacity.

Actually, as you get into these short-duration, high-intensity rainfalls, you introduce the risk of flooding from a second source: overwhelming the capacity of storm drains.

Storm Drains Designed for 2″ Per Hour

The storm drains in Kingwood are designed to convey about two inches of rain per hour. When you exceed that, water begins to back up in the streets. Exceed it enough, and water could actually enter homes – without sheet flow from Woodridge Village.

NHC Rainfall Prediction Spans 5 Days

The six-to-ten inch prediction issued by the National Hurricane Center for Beta spans five days. That’s good news. If ten inches were evenly spread out over five days, the streets, drains and ditches could easily handle two inches per day.

But those short, high intensity rainfalls – when you get two inches in five or ten minutes – represent a real danger. There’s just nowhere for the water to when it comes down that quickly.

Perhaps the Biggest Danger

Even if we got the predicted 6-10 inches all in one day, that’s still, at most, about 80% of the old 100-year rain which the detention was designed for.

I suspect the biggest danger from Beta may be those short, high-intensity cloud bursts or training feeder bands that dump a couple inches in five or ten minutes.

So keep your eye on the rain gage. Sign up for alerts at the Harris County Flood Warning System. Also, keep your eye on the forecasts; uncertainty still exists with Beta, its track and rainfall potential.

Posted by Bob Rehak on 9/19/2020

1117 Days after Hurricane Harvey and 1 year after Imelda

Beta Rainfall Estimates Increasing; 6-10 Inches Now Predicted for Lake Houston Area

Beta has turned toward the Texas coast. Adverse conditions will likely begin Sunday along coast and spread inland. The main forecast change since this morning? An increase in rainfall amounts, which could be significant. See rainfall section below.

A Flash Flood Watch will likely be issued on Sunday for the area.

Jeff Lindner, Harris County Meteorologist

Discussion

There has been little change in the overall organization of Beta today. Forecasters expect slow intensification as Beta approaches the TX coast.

Track: 

There have been no significant changes in the track reasoning today and the official forecast remains similar from earlier this morning. With that said, there is some uncertainty on when Beta will turn toward the N and NE near the mid Tx coast early next week, but generally impacts will be the same for much of SE TX.

Intensity: 

Given the lack of organization of the system and the lurking dry air to the west, it is now unlikely that Beta will attain hurricane intensity. The National Hurricane Center now keeps the system as a strong tropical storm as it approaches the TX coast. It should slowly as it moves NE or ENE up the coast. 

Impacts

Storm Surge: 

Water levels will rise along the upper TX coast beginning Saturday and worsen Sunday into Monday due to the expansion of the tropical storm force wind field. Expect swells reaching 15-25 feet over the NW Gulf. Four- to eight-foot waves could break on beaches. These large swells will lead to wave run up on top of the elevated tides.

Results:
  • Significant beach erosion
  • Damage to fragile dune systems.
  • Damage to coastal infrastructure
  • Inundation of low lying roads near the coast.
  • Once the water begins to rise on Saturday evening, some low lying areas may remain flooded into the middle of next week.
  • Overwash is likely on Hwy 87.
  • Ferry operations at both the Galveston-Bolivar and the Lynchburg sites may be impacted. 
Rainfall: 

While there is still some uncertainty, the storm could produce very heavy rainfall rates and amounts.

Jeff Lindner, Harris County Meteorologist

The rainfall forecasts have been adjusted upward, even though some models suggest only meager amounts of rainfall with Beta. Jeff Lindner, Harris County Meteorologist, currently predicts:

  • Coast: 12-18 inches
  • Coastal counties: 10-15 inches
  • South of I-10: 10-15 inches
  • South of Hwy 105: 6-10 inches
  • North of Hwy 105: 4-6 inches
Note that the rainfall amounts above are for a five-day total.

Given the forecast rainfall amounts…flooding of creeks and bayous across Harris County may flood depending on how the rain falls and how much falls at one time.

By Tuesday, when the ground is saturated, NOAA gives the Lake Houston Area a slight chance of flash flooding.

Six inches could fill smaller creeks; 7-8 inches could fill larger streams and bayous such as Buffalo. 

Addicks and Barker Reservoirs are currently empty.

Winds: 

Tropical storm force winds will be possible starting Sunday evening around Matagorda Bay with sustained 40mph winds likely spreading northward along the upper TX coast on Monday including Galveston Bay. Sustained winds of 55-65mph will spread up the TX coast Tuesday into Wednesday. Across Harris County wind will increase into the 25-35mph range on Monday and possibly 40-45mph range on Tuesday into Wednesday with higher gusts, especially near Galveston Bay.  

Note: Tropical storm force winds will begin to reach the coast on Monday…well ahead of any landfall of the center…due to the expanding wind field. Tropical storm force winds now extend 175 miles outward from the center of the storm.

Summary of Watches/Warnings In Effect

As of 4PM Saturday, 9/19/20:

A STORM SURGE WARNING IS IN EFFECT FOR

  • PORT ARANSAS TEXAS TO HIGH ISLAND TEXAS INCLUDING:
    • COPANO BAY
    • ARANSAS BAY
    • SAN ANTONIO BAY
    • MATAGORDA BAY
    • GALVESTON BAY

A STORM SURGE WATCH IS IN EFFECT FOR:

  • * BAFFIN BAY TEXAS TO PORT ARANSAS TEXAS INCLUDING BAFFIN BAY AND CORPUS CHRISTI BAY
  • * HIGH ISLAND TEXAS TO CAMERON LOUISIANA INCLUDING SABINE LAKE AND LAKE CALCASIEU

A HURRICANE WATCH IS IN EFFECT FOR:

* PORT ARANSAS TEXAS TO HIGH ISLAND TEXAS

A TROPICAL STORM WARNING IS IN EFFECT FOR:

  • PORT ARANSAS TEXAS TO INTRACOASTAL CITY LOUISIANA

A TROPICAL STORM WATCH IS IN EFFECT FOR:

  • SOUTH OF PORT ARANSAS TEXAS TO THE MOUTH OF THE RIO GRANDE
  • EAST OF INTRACOASTAL CITY LOUISIANA TO MORGAN CITY LOUISIANA

Protective Actions

  • Bookmark and monitor Harris County Flood Warning System throughout the storm. Familiarize yourself with the real-time inundation mapping feature.
  • Bookmark and monitor the National Hurricane Center for the most current updates on Beta.
  • Prepare now for a long period of coastal flooding and periods of heavy rainfall.
  • Voluntary evacuations have been recommended for:
    • Western end of Galveston Island, west of the seawall
    • Bolivar Peninsula
    • Low-lying areas of Chamber, Brazoria and Matagorda Counties (outside levee protection)
    • Low-lying areas of Seabrook.  

AlertHouston Recommends Taking These Steps Now

  • Ensure your family has 5-7 days of food, water, and necessary supplies.
    • This includes enough prescription medication for at least this duration, in case pharmacies and doctor’s offices are closed.
    • Consider the unique needs of small children, seniors, family members with access and functional needs, and pets.
  • Decide what you and your family will do if the storm impacts your area. Most City of Houston residents are not vulnerable to storm surge and do not need to evacuate before a hurricane or tropical storm. Vulnerable residents who require electricity may also consider evacuation in advance of a major storm. For a map of hurricane evacuation zones and mandatory evacuation areas, visit: houstonoem.org/hurricanes
  • Develop a family communication plan, so that you know who to check in with after a storm. Visit readyhoustontx.gov for more information on developing a plan.
  • Know how to turn off your utilities. This includes electricity, water, and gas. Only turn off gas if instructed by local officials or by CenterPoint Energy.

Posted by Bob Rehak on 9/19/2020 with data from the NHC, HCFCD, and City of Houston

1117 Days since Hurricane Harvey and 1 Year since Imelda

Hurricane Watch for Port Aransas to High Island

As of 4am Saturday, 9/19/20 (the 1-year anniversary of Imelda), the National Hurricane Center issued:

  • Hurricane Watches for Texas coast from Port Aransas to High Island
  • Tropical Storm Watches east of High Island into Louisiana and from Port Aransas to the Rio Grande
  • Storm Surge Watches from Port Mansfield, TX to Cameron, LA including all inland bays.

Discussion

There is an increasing risk of heavy rainfall and flooding along the northwest Gulf Coast Sunday through at least the middle of next week. Beta is forecast to move slowly toward and along or offshore of the coast through that time and create life-threatening storm surge.

Lake Friday, a USAF mission found a stronger tropical storm with winds of 60mph and a fairly large area of 40-50mph winds. Ships and oil platforms in the north-central Gulf of Mexico have reported winds above 40mph. The wind field is starting to expand toward the north.

Track: 

Beta is moving NNE at 12mph. Faster than expected. Beta will turn west around mid-day Saturday and decrease forward speed into early next week. This will bring Beta toward the middle Texas coast.

As Beta approaches the mid TX coast, weakening high pressure to the north will turn the storm toward the north and northeast. However, forecasters have lower-than-normal confidence as to when all this will happen.

The current National Hurricane Center forecast track is near the center of consensus for major global models, but shifts in this track will remain possible both toward the north or south.

Intensity: 

Beta intensified despite wind shear. As Beta moves over very warm western Gulf of Mexico waters, intensification will likely continue for the 24-48 hours. NHC now forecasts Beta to become an 80mph hurricane. As Beta begins to turn northeast and skirt the middle and upper TX coast, the storm may weaken. Some uncertainty remains in the intensity forecast.  

Tropical storm force winds will likely begin to arrive along the middle TX coast Sunday evening and spread northward into Matagorda Bay and along the upper TX coast by Monday. Hurricane conditions could reach the Matagorda Bay region on Tuesday.  

Impacts

Storm Surge: 

Water level rises along the upper TX coast will begin on Saturday and worsen Sunday into Monday due to the expansion of the tropical-storm-force wind field. This large wind field will also develop large swells over the NW Gulf of Mexico by Sunday into Monday with swells reaching 15-25 feet. On Sunday into Monday, expect 4-8 feet waves breaking on beaches. These large swells will lead to wave run up on top of elevated tides.

Large waves will accompany the higher tides. The prolonged nature of the event will result in significant beach erosion and damage to fragile dunes.

Expect inundation of low lying roads near the coast. Once the water begins to rise on Saturday evening, some low lying areas may remain flooded into the middle of next week.

Jeff Lindner, Harris County Meteorologist

Ferry operations at both the Galveston-Bolivar and the Lynchburg sites may be impacted. 

For SE Harris County:

From Saturday night into next week, coastal flooding will be possible in El Lago, Nassau Bay, Shoreacres, Seabrook and portions of Baytown near Goose Creek and Cedar Bayou.

This includes all areas around:

  • Clear Lake
  • Along Taylor’s Bayou in Shoreacres and Taylor Lake Village
  • Around the San Jacinto Monument and Lynchburg Ferry landing
  • In Seabrook areas along and east of Toddville Rd and in the waterfront area east of HWY 146.
  • The lower San Jacinto River at Rio Villa and other low lying areas south of US HWY 90.
  • Low lying areas in Galena Park and Jacinto City near the Houston Ship Channel
  • Lower portions of Greens and Hunting Bayous south of I-10.

Most flooding will happen in streets, low marsh lands, roads near Galveston Bay and around Clear Lake and some subdivisions streets.

Wave action from ENE/E winds across Galveston Bay of 2-4 feet will be possible on top of these tides along the west side of Galveston Bay and 1-3 feet in Clear Lake which may damage docks, bulkheads, and moored vessels. 

Rainfall

Rainfall will strongly depend on the track of Beta. Small changes could result in significant differences in rainfall amounts. Heaviest rains will likely be near the coast and offshore.

Any deviation of the track northward would bring the heavy rainfall further inland, likewise any south or east shift in the track would keep the heaviest rains off the coast.

  • Coast: 8-12 inches
  • Coastal counties: 6-8 inches
  • South of I-10: 4-6 inches
  • South of Hwy 105: 3-5 inches
  • North of Hwy 105: 1-3 inches

HCFCD models suggest that basin average rainfall totals of at least 6 inches would fill smaller creeks and bayous in Harris County (Willow Waterhole, Keegans Bayou, Willow Creek, Upper Little Cypress Creek).

Basin average amounts of 7-8 inches would fill Clear Creek, Hunting Bayou, Armand Bayou, Cypress Creek, Halls Bayou, Greens Bayou, White Oak Bayou, Buffalo Bayou, Cedar Bayou, and various smaller tributaries. 

Addicks and Barker Reservoirs are currently empty.

Winds: 

Tropical storm force winds may start Sunday evening around Matagorda Bay. Sustained 40mph winds likely spread northward along the upper TX coast on Monday including Galveston Bay.

Hurricane conditions will be possible near Matagorda Bay on Tuesday and across portions of coastal Matagorda, Brazoria, and Galveston Counties into Wednesday.

Across Harris County wind will increase into the 25-35mph range on Monday and possibly 40-50mph range on Tuesday into Wednesday with higher gusts, especially near Galveston Bay.  

Posted by Bob Rehak on 9/19/2020 at 4am based on data from the National Hurricane Center and Harris County Meteorologist Jeff Lindner.

1117 Days since Hurricane Harvey and 1 Year since Tropical Storm Imelda

Tropical Storm Beta Likely to Dump 4-6 Inches on Harris County, 10-12 Inches Near Coast

Preparations for Prolonged Coastal Flooding and Potential Inland Rainfall Flooding Should Begin now for Tropical Storm Beta.

As of 4PM CDT Friday, the National Hurricane Center predicts that storm surge, tropical storm and/or hurricane watches will likely be required for portions of the western Gulf coast tonight or on Saturday.

Forecast Track

Tropical Storm Beta is moving toward the north-northeast near 9 mph (15 km/h). This general direction should last through Saturday. Late Saturday or Saturday night, the storm should begin a slow westward drift into early next week. After that, Beta should recurve to the northeast.

Cone of uncertainty for TS Beta. Every point within the cone has an equal chance of receiving a hit from the center of the storm.

Don’t Focus on Exact Track Yet

Do not focus on the exact forecast track for Tropical Storm Beta, especially at days 3 to 5, as a high degree of uncertainty remains.

Regardless the forecast track, the center of Beta will approach western coast of the Gulf of Mexico Sunday night and Monday. Even if we don’t take a direct hit from Beta…

…Houston will likely be on the wet/dirty side of the storm.

10-20% Chance of Tropical Storm Winds for Houston

The Houston Area currently has a 10-20% chance of receiving tropical-storm force winds starting Sunday.

Probability of Houston receiving winds greater than 40 mph is 10-20%.
Those winds could arrive as early as Sunday morning.

Maximum sustained winds have already increased to near 40 mph (65 km/h) with higher gusts. Beta could reach near hurricane strength Sunday or Sunday night. Tropical-storm-force winds extend outward up to 105 miles (165 km) from the center.

Key Messages

According to the National Hurricane Center:

  1. Beta should strengthen and possibly become a hurricane, while moving slowly over the western Gulf of Mexico during the next few days.
  2. There is an increasing risk of heavy rainfall and flooding along the northwest Gulf Coast Sunday through at least the middle of next week as Beta is forecast to move slowly toward and along or offshore of the coast through that time. For additional information, see products from your local National Weather Service office.
  3. Monitor the progress of this system and future updates.

Beta could affect the Houston Area much of next week.

Impacts

Tides/Storm Surge: 

Strong ENE/E winds will push sea water toward the coast. Expect seas to build into the 8-15 foot range and waves to run up along the coast.

Expect at least 4.0-5.0 feet seas above the barnacle level. They could even reach near 6.0 feet. Impacts begin around 4.5 ft at several locations along the upper TX coast. 

Low lying roadways near the coast will likely flood at times of high tide and some locations could become isolated. Significant beach erosion is likely with elevated tides and large wave action lasting for several days and coastal infrastructure could be damaged. The expected tides on Sunday will likely be 1.5-2.5 feet higher than those experienced with Laura and Hanna.

DO NOT get caught off guard with the expected water level rise along the coast. Understand that low lying coastal roads may be inundated for a long period of time  

Rainfall: 

Squalls will increase in frequency and intensity into Sunday night and Monday and begin to spread farther inland. There will be a sharp cut off in the higher rainfall amounts from south to north over the area with amounts of 10-12 inches likely near the coast and even higher offshore. However, College Station will probably only see 1-3 inches.

Harris County Meteorologist Jeff Lindner predicts 4-6 inches over Harris County. 

These rainfall amounts will likely change

Winds: 

Tropical storm force winds could arrive by Sunday evening and slowly spread NE Monday and Tuesday. It is possible that some locations could see 24-48 hours of sustained tropical storm force winds with the slow movement of the system.

Posted by Bob Rehak on 9/18/2020 based on input from the National Hurricane Center and Jeff Lindner, Harris County Meteorologist

1116 Days after Hurricane Harvey and 365 Days after Tropical Storm Imelda

West Fork or Spring Creek: Which Contributes More Sediment to Lake Houston?

As the Lake Houston Area grapples with dredging, sedimentation surveys, sand trap studies and more, it’s important to understand where sediment comes from.

Month after month, I fly up and down the West Fork of the San Jacinto. More often than not, the confluence of Spring Creek and the West Fork (just west of I-69) looks like this.

West Fork (top) shows much more silt despite more flow coming from Spring Creek (left).

What Spring Creek Looked Like on Same Day

On this day (Friday, September 11), we took off from Intercontinental Airport and flew north over Spring Creek. Spring Creek looked like this.

Spring Creek north of Intercontinental Airport. Note how you can see the sandy bottom.

The difference in the water clarity is readily apparent. Yet in the 2000 Brown & Root study the authors said that Cypress and Spring Creeks contributed far more sediment. See Page 14. Sand miners, still quote and re-quote that study every chance they get.

What Accounts for Difference

So what accounts for the difference between the study and current visual observations? Mainly:

  • Upstream development
  • Sand mining
  • Storms that fall over one watershed, but not the other, on any given day

Twenty years after the Brown & Root study:

  • The heaviest development has shifted north into the West Fork watershed
  • Sand mining has expanded exponentially on the West Fork
  • Storms continue to fall over one or both watersheds.

Brown & Root’s findings on this one narrow issue (source of sediment) no longer reflect current conditions and visual observations.

Twenty square miles of sand mines between I-45 and I-69 have widened the West Fork tremendously since then, exposing far more sediment to floodwater. Worse, the mines’ dikes often breach, allowing millions of gallons of sediment to flow downstream. Even worse yet, the mines often pump water over the side of their dikes into the river or surrounding streams and forests.

The result is what you see above. Upstream from the sand mines, water flowed clearly on the West Fork, as it did on Spring Creek. Downstream, the West Fork looked like a sewer. The pictures below show some of the reasons.

Unless, otherwise noted, all the photos below were taken on 9/11/2020.

LMI River Bend mine. Not recent repair of breach and drainage ditch filled with silty water.
Same ditch goes under mine entrance. From there, the silty water goes into woods and then the West Fork.
At the LMI Moorehead mine, I spotted this pump.
At the same mine, this pipe and what looks like a fire hose send silty water into surrounding wetlands when the level in the pond at the right gets high enough.
One of the places where silty water enters the river.
Zooming out, you can see the source in the background.
Another mine where silty water leaks out of pits
The water collects in the woods and eventually flows into the West Fork.

The Result

This is the end result. The West Fork (top) is far more silty than flow from Spring and Cypress Creeks (left).

A Sampling of Previous Flyovers

West Fork (right), Spring Creek (left). Photo taken on 10/2/19.
West Fork (right), Spring Creek (left). November 4, 2019
West Fork (right), Spring Creek (Left). February 13, 2020
West Fork (top), Spring Creek (left). March 6, 2020.

I’m sure that when Brown & Root did its survey twenty years ago that Spring and Cypress Creeks contributed more sediment to Lake Houston. Today, however, I believe the West Fork contributes more.

It’s important to get this right if the community is to develop strategies that reduce the long term rate of sedimentation and save dredging dollars.

Posted by Bob Rehak on 9/18/2020

1116 Days after Hurricane Harvey

The thoughts expressed in this post represent opinions on matters of public concern and safety. They are protected by the First Amendment of the US Constitution and the Anti-SLAPP Statute of the Great State of Texas.

Mayor Pro Tem Martin Provides Additional Details on Purchase of Woodridge Village

Houston Mayor Pro Tem Dave Martin issued a press release today that provided additional details about the potential Harris County/City purchase of Woodridge Village.

Unanimous County Vote For Earnest Money Contract

As reported Tuesday evening, Harris County Commissioner’s Court voted unanimously to authorize the Harris County Real Property Division to negotiate an earnest money contract with Figure Four Partners, LTD. The purchase includes two tracts of land containing 267.35 acres located in Montgomery County, which could become the Woodridge Village Stormwater Basin.

The purchase price of $14,019,316.00 is about $5 million below the appraised value of the land. Martin thanks Harris County Judge Lina Hidalgo, Precinct One Commissioner Rodney Ellis, Precinct 2 Commissioner Adrian Garcia, Precinct 3 Commissioner Steve Radack, and Precinct 4 Commissioner Jack Cagle for their support. 

TWDB Loan Application

Said Martin, “This is the first crucial step in completing an inter-local agreement between the City of Houston and Harris County to purchase Woodridge Village.” This vote, coupled with the upcoming announcement from the Texas Water Development Board of the City’s eligibility to apply for a 0% interest loan to help develop the Woodridge Village project, will help reduce future flooding in Kingwood and the Lake Houston region.” 

During May of 2019, as well as Tropical Storm Imelda almost exactly a year ago, Woodridge Village contributed to flooding and heavy sediment deposited in much of northern Kingwood.  Mayor Pro Tem Martin called for the immediate stoppage of the planned development and sale of this site.

End-of-Year Deadline

Martin says he is happy to see the execution of the earnest money contract. It will lock in the purchase price for 120 days. The purchase of the property is contingent upon Harris County Flood Control District (HCFCD) entering in to an interlocal agreement with the City of Houston within 120 days of signing the earnest money contract. 

Last week, the City of Houston Public Works Director, Carol Haddock, submitted a letter of intent to the HCFCD Executive Director, Russ Poppe. It acknowledges the commitment by both parties, City and County, to execute a binding inter-local agreement no later than December 31, 2020. 

“A binding agreement for the proposed transaction can only be evidenced by HCFCD executing a finalized inter-local agreement which will need the approval of Houston City Council” said Martin. Martin also said he “is committed to working with every council office to gain their support of this interlocal agreement, as mutual support of projects to reduce future flooding citywide are key to a successful resiliency plan.” 

The location of the Figure Four Property is suitable for a sub-regional stormwater detention facility, which will help protect affected residents from future intense rainfall events.

Dave Martin, Houston Mayor Pro tem

Consolidation of Three Wastewater Treatment Plants on Woodridge Property

“Additionally, the City has identified a need for approximately 73 acres of the total site to serve as the location for a regional wastewater treatment plant,” says Martin. “This would facilitate consolidation of three wastewater treatment plants in the Kingwood Area.”

Two of these three plants were significantly impacted by flooding during Hurricane Harvey.  

The City would contribute cash for the portion of the site that would house the new wastewater treatment facility.

Land in Lieu of Cash for Floodwater Detention Portion of Property

For the floodwater-detention portion of the property, the City would contribute land in lieu of cash for Harris County Flood Control District flood-risk-reduction projects. 

Construction Funding Details Still to Be Worked Out

Once purchased, the City and District will work together to find additional funding to construct additional stormwater detention on the site to maximize downstream benefits. The Perry Homes/Figure Four Partners property only contains enough detention capacity at the moment to handle about 60% of Atlas 14 requirements. Atlas 14 is NOAA’s attempt to update rainfall precipitation frequency statistics. The need for the update became apparent after four so-called 500-year rains in five years (Tax Day, Memorial Day, Harvey, Imelda).

Despite the recent completion of three additional detention ponds, the Woodridge Village site currently only has about 60% of the detention capacity needed to handle a true 100-year rain (according to Atlas-14 requirements). Photo 9/11/2020.

The City has recently submitted an abridged application to the Texas Water Development Board (TWDB) for a $30 million grant/loan to fund a flood-damage-reduction project on Taylor Gully.

TWDB manages the capital Flood Infrastructure Fund (FIF) created by the 86th legislature in 2019, thanks to Texas State Senator Brandon Creighton and Texas State Representative Dan Huberty. The legislature mutually seeded the FIF program with approximately $790 M, the state has received applications requesting over $2.3 billion to date. Staff recommendations for applications to advance to the formal comprehensive application submittal phase are pending. 

“Ultimately, approval of this earnest money contract is a huge win for the City of Houston and Kingwood residents,” said Martin. “We hope to have more good news once the city has completed its application to the Texas Water Development Board for improvements to Taylor Gully, which will happen later this year.”

Posted by Bob Rehak on 9/17/2020

1115 Days after Hurricane Harvey and 364 since Imelda

Construction of Northeast Water Purification Plant in High Gear

During a flyover of the City of Houston’s Northeast Water Purification Plant Expansion project on 9/11/2020, I counted 13 construction cranes operating simultaneously on different parts of the site. The site stretches a full two miles from the start of the plant near the northeast corner of Beltway 8 to the tip of the water intake platform in Lake Houston. Here are photos that show the scope of this massive construction project.

The water intake platform stretches approximately 1100 feet out into Lake Houston.
The 108-inch intake pipes are larger than some pieces of construction equipment.
Looking NE toward Lake Houston along the path that the intake pipes will take through Summerwood.
Looking west toward the main treatment plant, with Beltway 8 in the background. Construction began in 2018.
Looking SW across the eastern portion of the new plant.
Looking SW across the western portion. The site is divided into about 10 sections each as large or larger than a city block.
A close up of construction activity in just one of the sections.
Looking straight east back toward Lake Houston from the western edge of the plant. Note the current water treatment plant in the foreground. It produces about 80 million gallons per day of fresh water.
Looking north over the center of the site.
Looking WNW. Note the NE corner of Beltway 8 in the top left. The plant expansion will provide another 320 million gallons per day.
For scale, note the size of the man on the scissor-lift in the red circle.

The plant expansion will supply 320 million gallons per day of treated water capacity in addition to the current 80 million gallons per day. So capacity will quintuple by completion in 2024.

Converting Area to Surface Water to Reduce Subsidence

The expansion of capacity will allow more water systems in the region to convert from groundwater to surface water. That should reduce subsidence and help avoid flooding.

Improved Techniques

According to the City, “The expansion will include conventional treatment processes like the existing plant that help coagulate, settle, filter, and then disinfect water.” Quality will exceed requirements set forth by the Texas Commission on Environmental Quality.

In addition, says the City, an advanced oxidation process called ozonation will disinfect water to help ensure that harmful organisms such as Giardia and Cryptosporidium are eliminated. Ozonation also helps eliminate taste and odor causing compounds, which improves the aesthetic quality of the water supplied by the plant.

Receive Updates

This construction update by the City of Houston shows additional ground-level and drone photos of the construction. You can sign up to receive future updates here.

Contractor Portal

Here is the main procurement portal for the project. Contractors looking for work on the site can sign up here.

Posted by Bob Rehak on September 17, 2020

1115 Days since Hurricane Harvey

How LIDAR is Used to Develop New Flood Maps

The Texas Water Development Board published a new video today in their Texas Water Newsroom. The title: “Data from the sky informs flood planning on the ground.” The video explains how Lidar (light detection and ranging) data helps develop accurate, up-to-date flood maps.

900X Higher Resolution

Surveyors can acquire high resolution data quickly from the air using pulses of light.

Lasers mounted under planes pulse hundreds of thousands of times per second producing incredibly detailed images of the terrain.

Texas Water Development Board

The data has one square-meter resolution compared to the old standard of 30 square-meters used in older USGS surveys. That’s a 900x improvement (1m x 1m vs. 30m x 30m) in resolution.

That increased resolution lets mapmakers see much more detail in the landscape, including low areas where water tends to pool during floods.

Play the Video

Filtering Out Buildings and Foliage Reveals Terrain

By filtering out portions of the spectrum, say those that have to do with buildings and foliage…

Screen Capture from TWDB Video

…scientists can reveal the terrain under them.

Lidar Now FEMA Requirement for Mapping

FEMA now requires the use of Lidar in floodplain mapping. As the state continues to grow rapidly, Lidar helps floodplain modelers better understand what is happening on the ground during a flood.

Inspiring the Next Generation

This is a fascinating little video. It has enough meat for curious adults. It also has a wow factor for students that might someday inspire interest in science, technology or engineering careers.

Updated Harris County Floodplain Maps

Harris County Flood Control District uses Lidar data to help develop the next generation of flood maps for the region. FEMA last updated the maps in 2007 as a result of massive flooding from Tropical Storm Allison. The District could release preliminary maps as early as 2022. But it could then take several more years for FEMA to review and approve them. The FEMA process involves a lengthy public comment period.

Source: Harris County Flood Control District.

Posted by Bob Rehak on 9/16/2020

1114 Days since Hurricane Harvey