The havoc caused byis best seen from the air -- and best explored through the eye of a drone, which can safely survey downed power lines, glide over damaged roofs and even search for pets in places no boat can go.
Drones and their pilots have arrived in Texas from all over the country. Craig Coker came from San Diego.
"I instantly dropped everything, my job obligations, kissed my wife and son goodbye, set a one-way ticket out here and tried to make it happen," he said.
Corker is part of loose-knit group of good Samaritans, pulled into formation by a new app that helps match drone operators with first responders, businesses and homeowners -- anyone who needs a closer look at the damage.
It works like a ride-sharing app. Enter a request for help through DroneUp.com and a smartphone app alerts qualified pilots in the area.
So far, DroneUp says its flown more than 2,300 missions with more than 400 pilots.
DroneUp founder Tom Walker says to think if it as a new kind of air force.
"We have retired law enforcement, retired military, we have film-making crews from out in California," he said. "We've been responding every minute of daylight we've had available."
Walker used to coordinate search and rescue for the Navy. Now, he's embracing modern technology for a new mission: helping Houston rebuild.