My mom and dad used to vacation on Granite Shoals, now known as Lake LBJ. They even acquired some property there in Kingsland a few blocks off the Llano arm of the lake. Not sure he actually witnessed it or just heard of it, but the Llano in that area was famous for a wall of water coming down that valley into the lake. The memory of that story has been with me this week.Many years ago, my young son and I tent camped at a brand-new state park, South Llano State Park near Junction. In the middle of the night a Park Ranger hailed us sleeping in the tent and informed us that we had about 45 minutes to leave the park or be prepared to stay for a few days. You see the entrance to the park crosses the river with a low water bridge. Earlier that day we were riding the water through the culvert that goes under the road at that bridge. Great fun albeit somewhat dangerous. At least the first time through. I elected to pack up the tent and get an early start home. By the time we left, the water was slightly over the bridge but Rangers directing traffic urged us across. We parked on the other side and as daylight approached, witnessed our first Hill Country flash flood. Grant it, it wasn't anywhere the magnitude of this recent disaster but still impressive. Watched it go from being a beautiful fun clear river to a muddy torrential current in a matter of 15 minutes. It rose 5' in that time. They said it was back to normal flow by midday.
They've since changed it to a high-water bridge
I was reminded of the Big Thompson flood of 1976 and then again in I believe it was 2013. Different sort of valleys, but same horrendous results.