BOULDER COUNTY, Colo. (CBS4) – A flash flood warning for the CalWood Fire burn scar in Boulder County is now listed as a considerable threat until 6:45 p.m. The National Weather Service in Boulder says Geer Canyon Drive to Lefthand Canyon and then to Highway 36 are at risk.
Flash flood warning for Calwood burn scar in Boulder County has been upgraded to CONSIDERABLE threat until 645 pm for flash flooding occurring in the area. Specifically Geer Canyon Dr. to Lefthand Canyon then to Hwy 36. For updates see https://t.co/ZiYzX7KttA. #cowx https://t.co/TSWRaM5qLu
— NWS Boulder (@NWSBoulder) July 31, 2021
The Boulder County Sheriff’s Office told residents along Geer Canyon and Lefthand Canyon to climb to higher ground until further notice.
Details about damage have not been shared. Evacuations orders have not been issued.

Calwood Fire burn scar (credit: CBS)
The CalWood Fire sparked in October of 2020. It burned more than 10,000 acres northwest of Boulder and destroyed 26 buildings and forced thousands to evacuate.