A drone flies into a smoke plume at a U.S. Geological Survey tall timbers research station, November 2000.

Tom Hoefen/USGS, Public Domain

When an earthquake, building collapse or cave-in strike, it's a race against the clock to save the lives of people trapped.

To help find victims in the rubble, engineers are hoping to adapt a trendy piece of technology made for the skies to go subterranean: Drones.

CU Boulder engineering professor Sean Humbert is leading a team in a national competition, the Subterranean Challenge. The U.S. Defense Advanced Research Projects Agency gifted the university a $4.5 million grant to fund Humbert's team.

The first phase of the Subterranean Challenge is in September. Humbert talked with Colorado Matters about the competition and the challenges of building drones, both aerial and ground-based, to explore surroundings with no light and no GPS.