Flash Floods

OK, the highest risk in Texas is Flash Flooding. It kills more people in Texas than all other weather related events combined. Mainly because people are impatient or just stubborn. It's kind of like relating it to trying to beat a train, it's just a bad idea, if you lose, it's usually final. If you cant see the pavement under the water, it may not be there. It may be a 10 foot deep hole of raging water.

If you have ever hydroplaned on the road, it is the same effect, except that the water is moving instead of you, and your car will float once it gets enough moving water under the tires:

Would you drive across this flooded crossing?

You may end up like this seconds later. Remember, the road may not be under the water as it looks.

Texas is prone to frequent, intense storms that can produce tremendous amounts of rain. In 1981, the “Memorial Day Flood” killed 13 after 10” of rain fell in four hours. In November 1974, a cold front dropped between four and ten inches of rain in central Texas resulting in the death of another 13. In June 1935, 22” of rain fell in three hours leaving 3000 Austin residents homeless. The 1921 “Great Thrall/Taylor Storm” still holds the record as the greatest of all continental U.S. rainstorms during 18 consecutive hours. 23.11” fell within 24 hours at Taylor; 36” fell in Thrall within 18 hours . . . 40” of rain in total. 224 people perished during this storm. Other great storms in 1915, 1900, and 1869 produced tremendous property damage and loss of life.

Here is a shot of Shoal Creek the day after the Memorial Day Flood of 1981. I was out in this event all night, and flooded out my vehicle 3 different times (2 separate vehicles). I was VERY lucky. It rained so hard, so fast that streets became 1-2 foot deep in 5-10 minutes.

Shoal Creek had dammed up at a bridge at 30th street and Lamar, with trees and such, and eventually broke loose, sending a tidal wave as high as the street lights (30 feet) down Lamar Blvd. One person was found clinging to the top of a light pole. 13 people died that night, some were never found. The flooding started in North Austin on Shoal Creek, North of Anderson Ln. and grew as it went. Over 3000 homes were destroyed. The caption for the above pic says that a dealership (Ford) lost 500 vehicles out of their parking lot. (yes, 500, remember-30 foot wall of water).

Below is an aerial shot of the Congress bridge in Austin in 1935, before the Mansfield dam was built. But, you would be surprised to know that there have been times when this could happen again. LCRA themselves stated that if the 26-32 inches of rain from the flood of 1998 that flooded San Marcos, New Braunfels, and downstream, would have fallen over the Highland lakes to the North, instead of where it did, 5 of the 8 existing dams would have been overtopped and at risk of failing. This photo shows just the lack of Mansfield dam. You could not imagine what this view would be if several dams failed and collapsed. MANY people would die and probably never be found, as the flood would continue all the way down to the coast, taking many more lives all the way down. Granted, this is an extreme example. Though the rains were 50 miles away from causing that scenario to occur. It can happen!

Congress Bridge looking North:

This is a shot of the 281 bridge at Johnson City after another flood on the Pedernales river, not dam controlled. Can you imagine encountering this at night? This is a US highway, not a farm road:

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