More information has come out, and one of the directors was monitoring the alerts -- the camp leadership knew about the afternoon's Flash Flood Watch -- and, per the family, the Executive Director got the Severe Flood Warning on his phone at 1:14. If he can be criticized, though I'm not sure the facts warrant it, it might be that he had staffers monitor the river and only when it started raining hard, an hour later, did he begin evacuations. It appears that wasn't what led to the deaths, though, as this flood was much worse than those seen historically and the girls who died and are missing came from cabins that historically were in a "safe" zone. It is also worth noting that the Executive Director, Dick Eastland, was one of those that died in the flooding as he was attempting to help rescue some of the youngest girls.
The camp is at the junction of Cypress Creek and the South Fork of the Guadalupe River and, with both rivers being so swollen, evidence is showing that the Guadalupe River actually started flowing backwards because of the amount of flood waters at the junction. This back flow, with the eddies it caused in the areas of the camp, is what appears to have caused the flooding of the "Handy Hut," where the missing girls were staying, that was well into the traditional safe zone.
So there are concerns about the speed of the response; as well as if the camp buildings, particularly ones that people slept in, should have been allowed to remain in the flood zones (and even in the relatively "safe" areas that flooded this year). It is a tragedy, for all involved, and hopefully it can lead to safer camps in the future.