Six Fort Carson helicopters took off from the Boulder airport Monday morning to haul search-and-rescue teams to isolated communities and scan the flooded landscape for people who remain stranded.

More than 100 Fort Carson soldiers were part of the effort Monday, working to add to the 700 people rescued by the post's 4th Combat Aviation Brigade since Friday. Pilots were working through patches of open sky between cloud formations to access mountain communities and isolated cabins.

"It's very demanding flying," said Col. Robert Ault, commander of the helicopter brigade.

The flight crews from the brigade's 2nd Battalion of the 4th Aviation Regiment include specialists in medical evacuation. Using a helicopter-mounted hoist, those crews can lower a medic to provide help in places too small for the helicopters to land.

So far, the helicopters have performed 25 hoist rescues.

The helicopters were sent to the rescue by Fort Carson's Brig. Gen. Michael Bills. Formal Pentagon orders authorizing the mission were expected Monday.

Ault flew on the missions Saturday.

"The devastation is pretty incredible," he said.

Monday, ground-based rescue teams worked to gather flood victims at helicopter landing zones for evacuation to the airport.

Colorado National Guard 2nd Lt. Skye Robinson said evacuees were being checked for medical problems before being taken to emergency shelters.

In the Pikes Peak region, the military was digging out from its own flood damage Monday.

A massive mud slide Thursday dumped boulders and other debris in front of the main entrance to the underground Cheyenne Mountain Operations Center.

Workers were using another entrance to access the mountain, and the underground part of the complex is undamaged, said Col. Travis Harsha, installation commander of Cheyenne Mountain Air Force Station.

Air Force engineers and soldiers from Fort Carson's 52nd Engineer Battalion worked through the weekend to clear debris and were expected to finish the job by Thursday.

The mountain houses a backup command post for the North American Aerospace Defense Command and has detachments from a variety of other military agencies who want to work in the bomb-proof safety of the mountain.

All but essential personnel were ordered home until the debris is cleared, Harsha said. Workers were assessing the full extent of damage, including whether the granite mountain itself was damaged.

Just east of the mountain complex, Fort Carson workers said it will take weeks to assess how more than 20 inches of rain over seven days damaged the 137,000-acre post.

Tank trails on the post's training area were gullied by the ran, and the training area on the south side of the post features dozens of new lakes, including one covering a rifle range, said Jim Rice, a civilian who oversees training on the post.

"Twenty inches - that's more rain than we typically see in a year," Rice said.

Limited training continued at the post as workers examined the extensive network of drainage ditches and erosion-control dams. "Of course one of the things you have to do in some of the cases is first let the water go away and then you go from there," Rice said.