Experts: Forecasting river flooding is tricky

Thursday, May 28, 2015
Experts: Forecasting river flooding is tricky
Residents who live near a river know that forecasters often miss the mark on river flooding. But why's it so hard to get right?

As water rises on the west fork of the San Jacinto River near Humble, experts quietly questioned the official forecasts for river height.

Wednesday afternoon Humble Resident Porfirio Valdez told Eyewitness News, "(The water) is up to my knees. They said we're supposed to get more water."

But forecasters said the river wasn't supposed to even be this high. On Wednesday morning, the river forecast from the National Weather Service predicted the water was going to fall. The prediction was off by more than foot. Since the forecast was released, the river level has risen. As of 4:45pm Wednesday, it was at 51.99 feet. Flood stage is 49.3. The National Weather Service now says the river should crest tomorrow afternoon at 52.4 feet.

Linda Martin, who lives a few blocks from the river told us, "I have everything packed." She and her husband Kenneth have been through flooding here twice before. The worst was in 1994 -- it's not expected to get that bad this time.

"How often do they get the forecast right?" Eyewitness News reporter Ted Oberg asked Kenneth Martin. Martin quickly replied, "They haven't got it right yet."

The National Weather Service admits this is a tough spot to predict river conditions. From their office in League City, a hydrologist explained that NWS experts rely on the same number of gauges as they did in the 1950s when Lake Houston was created. It is difficult to predict, they explained, how water flowing out of Lake Houston will back up the San Jacinto river here. With the limited number of data points, it is tough to accurately predict how high the water will rise.

Jeff Lindner with the Harris County Flood Control District agrees this is a tough spot to predict but the weather service does the best it can.

"The forecast obviously gets better as time goes by. As soon as the rain happens, the forecasts tend to be not as good but as time goes by every 12 hours they do new forecasts. The forecasts get more accurate and more accurate," he said.