Threat of flash flooding, mudslides across Colorado’s burn scars continues through Saturday

Fewer storms will impact Colorado’s burn scars Thursday compared to Tuesday and Wednesday, but the risk of flash flooding and mudslides remains high and will increase heading into the weekend.

There is still a threat of flash flooding Thursday over burn scars, with the exception of the Calwood Fire scar, due to slow-moving storms, according to the National Weather Service out of Boulder. Most of the storms will stay along and west of the Continental Divide.

By Thursday afternoon, the concern of flash flooding was such that the Larimer County Sheriff's Office issued a voluntary evacuation in the area of West County Road 43 in the Glen Haven area east to Drake, including The Retreat and Storm Mountain. The sheriff's office lifted the voluntary evacuation at approximately 7:47 p.m.

Westbound I-70 closed at Avon at around 4:17 p.m. due to reports of a mudslide in the area, CDOT said.

The Larimer County Board of Commissioners said it will consider a local disaster emergency declaration next week in the wake of this week’s mudslides and flash flooding in the Cameron Peak burn scar. One person died and three remain missing following a flash flood in Poudre Canyon.

A Flash Flood Watch is currently in effect for areas of central Colorado and south-central Colorado and will last through the evening due to the slow-moving storms.

Local heavy rain and flash flooding is possible in the following areas:

• Chaffee County below 9,000 feet

• Eastern Sawatch Mountains above 11,000 feet
• La Garita Mountains above 10,000 feet

• Leadville Vicinity/Lake County below 11,000 feet

• Saguache County east and west of Continental Divide below 10,000 feet

• Western Chaffee County between 9,000 and 11,000 feet

• Western Mosquito Range/east Chaffee County above 9,000 feet 

• Western Mosquito Range/east Lake County above 11,000 feet

• Eastern San Juan Mountains above 10,000 feet 

• Upper Rio Grande Valley/eastern San Juan Mountains below 10,000 feet

Lake County around Leadville received the heaviest rainfall in this area Wednesday, meaning it is now the most susceptible to flash flooding, NWS said.

The Colorado Water Conservation Board said the threat of burn scar flooding for the East Troublesome Fire and Grizzly Creek Fire is high Thursday, and moderate for the scars at the Cameron Peak Fire and Pine Gulch fire.

At around 2:45 p.m., a Flash Flood Warning was issued for the East Troublesome burn area in North Central Grand County until 5:30 p.m. The NWS said heavy rain is falling between mile markers 5-15 on CO 125.

As of 9:45 a.m., the chance of storms in the foothills and eastern plains is lower than earlier this week. Storms will stay closer to high terrain, where moderate or high risks exist. At the maximum, rainfall in those areas could add up to 2 inches in one hour, which could cause flash flooding, debris slides and mud flows, according to the Colorado Water Conservation Board.

On Thursday morning, precipitable water at Grand Junction measured 1.18 inches, which the Colorado Water Conservation Board said is within 10% of its daily record for this time of year. The Denver area’s precipitable water level was also considered high at 1.07 inches.
Looking ahead, moisture will increase Friday and Saturday, which is expected to elevate the threat of flash flooding, according to NWS.

Storms may decrease by Saturday, but the risk of burn scar flooding will remain “significant,” NWS said. By the afternoon, the mountains, San Luis Valley and I-25 corridor may see storms that initiate a Flash Flood Watch. Severe storms Saturday may drop hail 1 inch in diameter and wind gusts up to 60 mph.

By Sunday and Monday, a drying trend will begin with low risks of flooding at the burned areas.

Monsoonal moisture caused flooding in the Poudre Canyon area of Larimer County Tuesday, leaving one woman dead and three missing. At least five homes were destroyed, Larimer County officials confirmed.

Highway 14 through Poudre Canyon closed Tuesday early evening and reopened around 3:30 p.m. Wednesday.

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The Poudre River is closed for all uses, according to the Larimer County Sheriff's Office. The U.S. Forest Service also announced closures for all Forest Service recreation areas in the Poudre Canyon through July 28.

A mudslide near the East Troublesome Fire burn scar closed Highway 125 between Cabin Creek and Buffalo Creek on Wednesday. The highway reopened around 12:50 p.m. Thursday. Nobody was injured in the slide.

By 3:40 p.m. Highway 125 closed again between Trail Creek County and County Road 54 due to a mudslide.

Interstate 70 was closed Tuesday evening through Glenwood Canyon as crews worked to clear the road of five mudslides, and stayed closed for about 25 hours, reopening late Wednesday. The area has seen several closures in past weeks due to the Grizzly Creek Fire burn scar above the highway. The 32,631-acre fire burned in the canyon in 2020.

Crews are closely monitoring the forecast for future Flash Flood Warnings. The highway will close if there’s a threat of another slide.