A new wave of rain is threatening to hamper airlifts from flooded areas still out of reach in the US state of Colorado.

The widespread flooding has killed at least seven people, officials said on Sunday, as the search for people stranded from the Rocky Mountain foothills to the plains of northeastern Colorado grew more difficult.

About 1,500 homes have been destroyed and another 17,500 damaged, according to an initial estimate released by the Colorado Office of Emergency Management on its website.

Al Jazeera's Tamara Bans reports from Colorado, US.