DENVER (KDVR) — Monsoon season means the possibility of trip-altering closures on Interstate 70, especially through the Glenwood Springs area, where rain on the Grizzly Creek burn scar heightens the risk of mudslides.

While mudslides closed the interstate for weeks in July 2021, there was “very little flooding” last summer, according to the Colorado Department of Transportation. Travel officials expect even fewer closures in the canyon this summer.

Still, the risk remains. Here’s what to know if your travels are derailed because of an I-70 closure.

When will I-70 be closed?

CDOT has updated the thresholds for when I-70 will be closed through Glenwood Canyon this summer.

I-70, Glenwood Canyon rest areas and recreation path will close under these circumstances:

  • If a flash flood warning is issued for the Grizzly Creek burn scar
  • If 1 inch of rain is in the forecast for the next hour
  • If 0.6 inches of rain is in the forecast for the next 30 minutes

In the event of a closure, all traffic will be evacuated from I-70 in Glenwood Canyon. I-70 will be closed in both directions from Glenwood Springs (exit 116) to Dotsero (exit 133), and a closure point will be in place at West Rifle (exit 87) to detour eastbound traffic onto northbound Colorado 13.

Motorists will continue to have access to Glenwood Springs and the Roaring Fork Valley, according to CDOT.

Only the rest areas and recreation path will be closed in these cases:

  • If a flash flood watch is issued for the Grizzly Creek burn scar
  • If the forecast shows a 50% or greater probability of exceeding the thresholds above (1 hour and 30 minutes) in the next 24 hours

I-70 closure detour around Glenwood Springs

Unfortunately, a closure of I-70 through Glenwood Canyon will add hours to your journey.

The northern detour around the closure is generally the best route, according to CDOT. But travelers are urged to check COtrip.org or the COtrip Planner app (available online and for iOS and Android) to make sure the northern route is the best detour — sometimes crashes or closures can affect conditions.

Here is the northern detour route:

  • Westbound I-70: Westbound motorists from the Denver metro area can travel north around the closure via U.S. 40, Colorado 9 or Colorado 131. Travelers can then continue west on U.S. 40 and then south on Colorado 13 to complete the alternate route and return to westbound I-70 at Rifle (exit 90). Motorists should anticipate heavy traffic at the Silverthorne interchange (exit 205) due to construction in the area.
  • Eastbound I-70: A traffic control point is in place at eastbound West Rifle (exit 87) to guide motorists to the northern alternate route. Visitors and local traffic traveling eastbound on I-70 to Glenwood Springs and destinations in the Roaring Fork Valley will have access to eastbound I-70 in order to reach their destination.
A screenshot of the COtrip Planner map showing live road conditions on the morning of Aug. 3, 2023. (COtrip.org)

I-70 travelers from Denver should also be aware that construction is underway through 2028 for the Floyd Hill expansion project from Evergreen to eastern Idaho Springs.

I-70 detours to avoid — for your safety

Travelers considering a southern detour around the closure should remember that traffic impacts and delays continue on U.S. 50 near Montrose, where the Little Blue Creek Canyon construction project continues.

“Depending on the circumstances of an I-70 Glenwood Canyon closure, CDOT may ask the U.S. 50 Little Blue contractor to pause construction so that motorists can use the U.S. 50 alternate route,” CDOT’s Elise Thatcher told FOX31.

CDOT strongly discourages travelers from using these routes:

  • Cottonwood Pass Road (in Eagle/Garfield counties)
  • Hagerman Pass
  • Eagle/Thomasville Road
  • Other county or forest service roads in Eagle, Garfield and Pitkin counties

CDOT warns that these roads are not built for heavy traffic or commercial oversized vehicles. Many of these four-wheel-drive roads also lack cell phone coverage.

Most importantly: Check the weather

No matter the season, travelers should always be aware of the weather forecast before journeying into the high country. If there is rain in the forecast, I-70 could close.

Bookmark these Pinpoint Weather forecast tools to keep them handy for when you need them:

Be sure to download the free Pinpoint Weather app to get vital weather information sent straight to your phone.