January 2 – Increased Flood Risk

The National Weather Service has issued a Flash Flood Watch for much of our region until noon on Thursday, January 3. This morning’s forecast is continuing to show much of the Brazos River Watershed, including Fort Bend County, receiving between 1 to 3 inches of rainfall with the potential for isolated amounts of 4 to 5 inches.

NWS Houston/Galveston Flash Flood Watch Image (01/02/19 4:24 AM)

NWS Houston/Galveston Rainfall Potential Image (01/02/19 4:24 AM)

Based on this morning’s forecast, the heaviest rains continue to be to our north and east; however, with much of our soils still saturated, any rainfall received will quickly be converted to runoff which can potentially cause street ponding and rises in our local watersheds. Final impacts will depend on the final location and volume of rainfall received.  

PivotalWeather.com Rainfall 48-Hour Precipitation Forecast (01/02/19 6:00 AM)

This rainfall has the potential to create a minor flood event on the Brazos River, downstream of Bryan/College Station. Given the rainfall potential over the next 12 to 24 hours, the WGRFC has issued updated forecasts for the Brazos River. As of this morning, the WGRFC is forecasting the Brazos River in Hempstead peaking around Gage Elevation 52.4 feet. The current forecast for Richmond shows a similar rise; however, at this moment the forecast ends at Gage Elevation 42.7 feet with no crest shown due to the published forecast window.

WGRFC 8:13 AM Forecast for the Brazos River in Richmond

Based on historical events, Richmond has typically hit between Gage Elevation 47 and 50 feet when Hempstead has hit above Gage Elevation 50. At this moment, The biggest thing to watch is how the rainfall will actually be distributed throughout the watershed, especially since the entire watershed from Waco to Rosharon is forecasted to receive at least 1.5 to 2 inches of rainfall. Depending on the final distribution and timing, we could see the Brazos River through Richmond to hit similar levels that match some of our historical events such as the May 2015 and October 1994 flood events when the Brazos River in Richmond hit around 50.

As a disclaimer, the above statement is solely based on historical events; however, please remember that all events are different and can produce different results. This is especially the case as the hydraulics of the Brazos River change due to sediment deposits, erosion, etc. Please continue to follow the official forecasts by the WGRFC for more information as things develop.

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