More than 100 people are dead and 150 known to be missing in Texas Wednesday from flooding but questions remain about how the effects of the deadly disaster could have been mitigated.

As the Guadalupe River swelled from a wall of water heading downstream, sirens blared over the tiny river community of Comfort -- a last-ditch warning to get out for those who had missed cellphone alerts and firefighters going street-to-street telling people to get out.