Travelers on I-70 through Glenwood Canyon this season will notice new protocols for highway closures in response to flash flood warnings, as the Colorado Department of Transportation is attempting to keep the major artery open as much as possible.

Rather than shutting down the entire canyon highway when flash flood watches are issued, personnel will be deployed at critical points to monitor weather conditions and shut down the road if flash flooding threatens travelers.

“The Colorado Department of Transportation, in partnership with the U.S. Forest Service (USFS), National Oceanic and Atmospheric Administration (NOAA), the U.S. Geological Survey (USGS) and others, has updated safety protocols for Interstate 70 through Glenwood Canyon ahead of the 2025 summer travel season,” the transportation department said in a news release last week.

In the years since the 2020 Grizzly Creek forest fire on the north slopes above Glenwood Canyon, I-70 has been subject to repeated shutdowns during summer storm season for safety reasons.

The abundance of caution on the part of state officials resulted in a 220-mile, 4-hour detour that takes drivers through Silverthorne, Steamboat Springs, Craig, Meeker and Rifle.

On July 29 and again on Aug. 1, 2021, unprecedented monsoon rains dumped as much as 2 to 4 inches of rain in an hour on the Grizzly Creek burn scar, causing multiple mudslides.

At Blue Gulch, the rainwater gathering more than 3,400 feet above the canyon floor soared over a 200-foot cliff half a mile north of I-70 and poured into the ravine below. When the cascade of mud and rock hit the highway, both upper and lower decks of the roadway were covered with up to 10 feet of debris. Damage to the highway was extensive.

Since that devastating flash flood, state officials have put motorist safety above convenience, often shutting down the entire highway from Dotsero to Glenwood Springs when flooding is likely.

But thanks to years of flash flood mitigation work, vegetation recovery above the highway and improved cell phone and emergency communications in the canyon provided by AT&T, the threat of catastrophic mudslides and debris flows onto the highway has been significantly reduced, according to CDOT.

This season, CDOT crews will use standard traffic control measures at all closure points and will actively monitor conditions in Glenwood Canyon using cameras and personnel on the ground.

Previously, the highway would close when a flash flood warning was issued. This summer, crews will continuously monitor conditions and keep I-70 open, along with rest areas and the recreation path, as long as it remains safe. This also includes maintaining access for both private and commercial rafting groups.

Motorists planning to travel on I-70, visit rest areas or use the recreation path in Glenwood Canyon should pay attention to road conditions on COtrip.org and the COtrip Planner App, as well as nearby overhead I-70 digital message boards and weather forecasts, the transportation agency said.