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- Feb 17, 2013
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When I was stationed at Ft Hood I would ride my motorcycle around Texas when I could. One day I ended up at some park on the way to Waco. I was going to see the race boats on the Brazos. The park was named Iron Bridge park. It had a creek running under it maybe a foot or two deep. I remember there was a giant measuring stick on the side of the bridge. I think it went up to 25 feet!!!!! Thats why the bridge looked like it could handle a bombing raid from thd 8th Airforce.Crazy!!!!
The area in Texas to the west of IH35 from Hillsborough (where IH35E and IH35W merged) all the way down to San Antonio skirts the boundary between the Blackland Prairie area and the Edwards Escarpment aka the "Broken Hills". When we get a tropical storm (they've been known to show up in all 12 months) come in and squat over an area like Harvey is doing, we get huge amounts of rain and the creeks and gullies fill up rapidly, running fast and deep.
Back in 1921, over September 09/10 Williamson County had a hurricane eye come in and settle in, very much like what Harvey is doing now.
Thrall Tx had 23.4 inches of rain in 6 hours, 31.8" in 12 hours, 36.4" in 18 hours and either 38.2" or 39.7" (depending on whose book you read) in 24 hours.
Seven miles west of Thrall, Taylor, the town I grew up in, had 34+" and Granger, 11 miles north of Taylor had 30"+ during the same 24 hour period. The San Gabriel River, which bisects Williamson from east to west between Taylor and Granger, usually ran about 2 or 3 feet deep that time of year back then. No one knows how deep it was at the river because no one could get to it to see. Usually running about 10 to 15 feet wide, the river was later determined to have been running over 5 miles wide.
My grandmother was 13 at the time. She told us that they had over a foot of water running through the yard heading to the creek nearly 1/4 mile away. The house was 8 miles north of Granger, about 20 miles from Thrall.
That means drawing a 20 mile radius around Thrall, if the whole area was covered by only a single foot of water, there would have been nearly 3.6 BILLION gallons of water sitting in just that small area alone as a static snapshot.
Hurricanes can drop a huge amount of water in a short time.