NWS Issues Flood Watch
Early this morning, the National Weather Service issued a flood watch for areas north of the Houston Metropolitan area. It will remain in effect through midnight tonight.
As of 2PM, NWS extended the flood watch to include Harris, Fort Bend, Brazoria, Galveston, Chambers, and Liberty Counties through Wednesday morning.
Harris County Meteorologist Jeff Lindner predicts heavy rainfall toward I-10 and the coast by tonight. More rain on top of what has already fallen along with elevated creeks and streams led to issuing the flood watches.
Five of the six watersheds most in danger of flooding flow into the Lake Houston Area. And the SJRA is releasing water from Lake Conroe.
Forecast for Next 48 Hours
The ground has generally been saturated by yesterday’s rain and NWS predicts additional heavy rains today and tomorrow. The total could approach another 4.5 inches in the Lake Houston Area and even more to the north and west.
Those same areas received the highest rainfall totals yesterday on 1/22/24. Luckily, the rain has been fairly spread out until now.
Only One Stream in Region Currently Out of Banks
The San Jacinto West Fork came out of its banks at Highway 30 yesterday afternoon and is still out at noon on Tuesday, although waters have receded approximately a foot since the peak early this morning.
However, the Harris County Flood Warning system is also flashing warning signs for areas in the upper Cypress and Spring Creek Watersheds. All of those creeks are still within their banks as of noon Tuesday.
The map below shows the rainfall totals for the last 48 hours. Note how they peak in the north and west.
A gage on the Trinity River just west of Lake Livingston (not shown below) received 4.8 inches in the last 36 hours.
Lakes Conroe and Houston Both Releasing Water
Heavy rains north and west of Lake Conroe have led the San Jacinto River Authority (SJRA) to open the floodgates at Lake Conroe. The lake level is currently at 201.61 feet (normal 201) and the SJRA is releasing at a rate of 2665 cubic feet per second as a precaution against much larger releases later.
The City began releasing water from Lake Houston last Sunday in anticipation of this rainfall. At the noon hour on 1/23/24, Lake Houston is still slightly below normal. It is at 41.57 feet; normal is 42.4. But there’s much more headed toward the dam.
How to Monitor Flood Potential
If you live near water, monitor conditions closely.
- Houston/Galveston office of the National Weather Service for weather forecasts.
- Harris County Flood Warning System for channel forecasts, rainfall totals, inundation mapping, and historical flooding information near you.
- Coastal Water Authority for Lake Houston levels.
- San Jacinto River Authority for Lake Conroe levels and release rates.
Remember: It’s not just the rain that falls where you are at that causes flooding. Look upstream to see what’s coming at you.
We should begin to see some rises in the Lake Houston Area soon because of Lake Conroe releases and the heavy rainfall upstream on Spring and Cypress Creeks. They are the three main tributaries that govern the volume of water flowing into Lake Houston from the west.
The West Fork at US59 is still well below flood stage because of the Lake Houston release. Regardless, the river rose there almost 2 feet in the last 16 hours.
Streams Most in Danger of Flooding
Jeff Lindner, Harris County’s meteorologist, expects the heaviest rains to shift from the north toward the south later today. Lindner said, “Rises will continue along upper Spring and upper Cypress Creeks this morning as upstream run-off moves downstream.”
“No flooding is currently expected,” continued Lindner, “but high flows in these creeks will continue today into tomorrow. This area will be particularly sensitive to additional rainfall and will need to be monitored closely.”
“Also watch the San Jacinto River basin,” said Lindner. “Due to the widespread nature of the rains, run-off is starting to work into the basin and minor flooding will be possible along the East Fork of the San Jacinto River later this week.”
Lindner says the Harris County streams most in danger of flooding include:
- Cypress Creek
- Spring Creek
- Little Cypress Creek
- Lower South Mayde Creek
- Willow Creek
- San Jacinto River basin
All but Mayde Creek flow into Lake Houston. If you are unfamiliar with the watersheds around us, here is a map.
Posted by Bob Rehak on 1/23/24
2338 Days since Hurricane Harvey
