MANITOU SPRINGS, Colo. — What was warned about for months since last year's deadly Waldo Canyon Fire in Colorado Springs finally happened: flash flooding near the burn scar that shoved debris into homes and moved vehicles.

More than a half inch of rain fell in less than 20 minutes Monday, causing mud to flow into 20 houses in Manitou Springs and western Colorado Springs.

Manitou Springs Police Chief Joe Ribeiro said at least three homes were total losses, and at least 11 vehicles were damaged, The Gazette reported.

The downpour over the burn scar forced more than 160 people to briefly evacuate a low-lying trailer park, and it also closed U.S. 24 for several hours.

National Weather Service meteorologist John Kalina said the damage could have been much worse if the storm had settled over the area. He said 0.59 inch of rain fell in less than 20 minutes.

"That's pretty intense rain rate, and that helped to cause the issues that we're seeing today," Kalina said.

"It was raining buckets and all of a sudden I heard this freight train," Tina Webber, who lives in Manitou Springs, told The Gazette (http://bit.ly/16LDX2d ). "I came running around my house and I see this wall of water with this perfect white mattress on the front of it coming down the canyon."

"It was an 8-foot wall of black debris and boulders and trees. There was no stopping it," Webber said.

The potential for flooding has worried officials since the June 2012 Waldo Canyon Fire burned 347 homes and killed two people. Authorities have said the fire was human-caused but have released no other findings.

El Paso County, Colorado Springs and Manitou Springs have held briefings for residents on the threat of flash flooding in the burn scar area.

In June, the U.S. Agriculture Department said it was sending nearly $20 million to repair watersheds and mitigate flood potential in both the Waldo Canyon and High Park Fire burn areas. Work includes mulching, re-seeding and shoring up water channels.