Flood Watches and Warnings Extended, Streams Starting to Flood

Update: I just got word that SJRA is starting to increase the release rate from Lake Conroe to up to 19,500 cubic feet per second as of 9PM Wednesday night. Their modeling suggests that will cause the West Fork at US59 to peak at 53.5 feet – above the major flood stage. The previously forecast peak this afternoon was 51.8 feet and flood stage is 49.3 feet. People in low-lying areas near the river, even those in elevated homes, should consider evacuating. The river may not recede below flood stage before next weekend.

National Weather Service (NWS) flood watches and warnings have been extended. Continued heavy rainfall today has many streams especially in the northern part of the Houston Region coming out of their banks.

NWS Houston/Galveston Office predicts that showers and thunderstorms will continue through at least 7am tomorrow, with most areas experiencing a 60% chance of rain. While additional accumulations should be mild tomorrow, the Weather Service warns that higher amounts are possible in thunderstorms. The last wave of this marathon mess should push through overnight tonight. The sun may poke out by Thursday afternoon.

*Rain-swollen confluence of San Jacinto West Fork (r) with Spring Creek (l) at US59* *at noon Wednesday*. *The normal river bank is defined by the arc of small shrubs just right of center.*

*Low-lying streets in Lakewood Cove were already under water at noon today. West Fork is in upper left.*

In the meantime, we aren’t out of the woods yet.

Flood Watch Through Noon Thursday

NWS has extended flood warnings and issued flood watches for large parts of SE Texas.

*A flood watch means flooding is possible* *in the highlighted areas above.*

Flood Warning Through Midnight Tonight

Much of the area picked up another 1-3 inches today with much higher totals off to the north and northwest from Columbus to Brenham to Lufkin where a swath of 8-12 inches has fallen since Sunday night, according to Harris County Meteorologist Jeff Lindner.

*A flood warning means flooding has already occurred or is expected* *in highlighted areas above.*

Upstream run-off continues to work into creeks in northern Waller, northwest Harris, and Montgomery Counties along with the San Jacinto River basin.

Areas with Flooding Concerns

The Harris County Flood Warning System shows that several channels are already out of their banks (red dots) or in danger of coming out (yellow triangles).

*Harris County FWS as of 5PM on 1/24/24*

For up-to-the-minute readouts on the status of a channel near you, go to Harris County Flood Warning System. Use the “Map view options” to select Channels, Channel Status. Under site selection, choose All.

Streams with Highest Flood Risk

According to Lindner, several creeks feeding into Lake Houston are already flooding. They include:

Upper Spring Creek:

Low land flooding of rural lands near the creek as well as roadway crossing across the creek is occurring from upstream of SH 249 to the headwaters. Several low bridge crossings over the creek are flooded and some impassable. The creek will peak tonight and begin a fall into Thursday. No structures have flooded. Any low-land flooding downstream of SH 249 will be limited as the capacity of the channel increases.

Little Mound/Upper Cypress Creeks:

Low-land flooding is ongoing along Mound Creek from eastern Waller County into extreme western Harris County. Water levels will peak tonight, then fall into Thursday. Flow from Little Mound Creek will route into upper Cypress Creek where a rise to near bankfull is likely around Sharp Rd. Sharp Rd may become inundated on Thursday. No structure flooding foreseen.

West Fork of the San Jacinto River:

The river is rising and will exceed its banks this evening and continue to rise into moderate flood levels over 50.0 ft on Thursday with a forecasted peak near 52.0 ft on Friday. At these levels, low land flooding will occur along much of the river from upstream of US 59 to Lake Houston.

The US 59 turn arounds under the US 59 bridge crossing will be under several feet of water. The City of Houston has already closed off traffic under the turnarounds.

Several streets on the north bank of the river will be flooded including Lakeshore, Northshore, River Bend, and Lake Point.

The few structures in this area are elevated and could potentially become cut-off into the weekend as water levels remain elevated. At these levels back water will also begin to affect tributary drainage channels into the river and higher than normal water is likely along these tributaries. No flooding of homes is expected in Kingwood.

East Fork of the San Jacinto River:

The river is rising and will exceed its banks early Thursday and then continue to rise into moderate flood levels by late Friday into Saturday. FM 1485 west of the river bridge will be flooded and impassable for an extended period of time. Additionally, some roads on the west side of the river just downstream of FM 1485 will be flooded and elevated structures cut-off. Elevated structures downstream on the east river bank off River Terrace Rd will be cut-off. The river is forecasted to remain well above flood stage through the weekend.

Lake Houston:

Water levels will be elevated likely to the top or just over the top of bulkheads and docks in the lake as upstream flows are passed through the lake. Additionally, large amounts of floating debris will make any boating hazardous into the weekend.

Lower San Jacinto River below Lake Houston:

While flooding is currently not forecasted, given the amount of water that will be moving through Lake Houston and over the spillway, a rise to potentially near flood levels is certainly possible downstream of Lake Houston at Sheldon, Banana Bend, and Rio Villa. Low lying roads near the river may become inundated. Any possible flooding at locations below Lake Houston would be this weekend.

Lake Releases

At 5PM 1/24/24, the SJRA dashboard showed that Lake Conroe as at 203.78 feet, almost 3 feet above its normal elevation of 201 feet. SJRA has temporarily closed Lake Conroe because of high currents, submerged objects and floating debris.

Because of continuing high inflows, SJRA was releasing 16,525 cubic feet per second at 5PM. They have steadily increased the volume released for the last three days.

To put this in perspective, 16,525 CFS is half the discharge rate of Lake Conroe during the October 1994 storm. And it’s about a fifth of the maximum release rate during Hurricane Harvey in 2017.

Farther south, Houston Public Works has had its flood gates wide open since Sunday. Regardless, water is now going over the spillway. Normal lake level is 42.4 ft and it’s currently at 43.57 ft.

According to the Harris County Flood Warning System, water has been going over the top of the spillway since 4AM this morning.

Helpful Resources

Weather conditions can change rapidly. For current information, go straight to these sources:

Posted by Bob Rehak on 1/24/24 at 6PM

2339 Days since Hurricane Harvey