What happened in Glenwood Canyon should have been expected, CSU professor says

damage from mudslide on i-70 through glenwood canyon_august 1 2021.jpg
Posted at 6:06 PM, Aug 11, 2021

DENVER – A Colorado State University professor said Wednesday that the large debris flows which shut down Interstate 70 through Glenwood Canyon for nearly two weeks should have been “expected” given what’s going on with Colorado’s climate.

Lee McDonald, professor of Ecosystem Science and Sustainability at CSU, told Denver7 that even though climate change has exacerbated seasonal weather patterns across the state, post-fire runoffs “have been going on in Colorado for a very long time,” we just hadn’t experienced one for a while.

“Not until the Buffalo Creek Fire in 1996 people didn’t really appreciate the magnitude of the fire flood sequence that other people like in Southern California have appreciated,” McDonald said. “I don’t think people initially appreciated 30 years ago the magnitude of the fire flood sequence we can have.”

McDonald, who has worked on post-fire runoff for decades, wrote in 2018 the problem is likely to get worse as climate change continues to increase not only the severity but the length of Colorado's fire season.

He suggested in an article for The Conversation that one of the ways to combat destructive debris flows in the future would be to implement more strict zoning rules in mountain areas to minimize construction in vulnerable spots that could potentially see destructive debris flows.

“We didn’t see anything like what we’re seeing right now”

Colorado Public Radio recently sat down with Ralph Trapani, one of the engineers who managed construction of I-70 through Glenwood Canyon, to talk about the infrastructure of that part of the highway.

Trapani told CPR News that initially, the thought was to build I-70 to be less vulnerable, calling the initial plans of I-70 through Glenwood Canyon a “European-style high line viaduct.”

That idea was ultimately nixed by designers on the citizen’s committee.

Trapani told CPR News, however, that the chance for mudslides was studied but that, at the time, the risks were of a different magnitude.

“We did exhaustive geologic reconnaissance in the canyon, both surface reconnaissance and also subsurface reconnaissance using state-of-the-art methods for the time,” Trapani said. “We didn't see anything like what we're seeing right now. … our reconnaissance never showed any events that were shipped, bringing down these amounts of large rock from the upper reaches of Glenwood canyon. There was no evidence of that at all.”

I-70 partially reopening Saturday afternoon

I-70 through Glenwood Canyon will reopen by Saturday afternoon, according to both Gov. Jared Polis and the Colorado Department of Transportation (CDOT).

All lanes will be open except for a 3/4-mile stretch near Blue Gulch at milemarker 123.5, which will have just one lane moving in each direction, CDOT officials said.

“We are in many ways fortunate that the structural damage wasn't worse,” Polis said during a a tour o the damage Wednesday morning. “There could've easily been additional holes, there could've been larger gaps, that could've taken days or weeks to repair."

The governor said reopening that section of the highway is the state’s top transportation priority at this moment.

Denver7 spoke to truck drivers and representatives of trucking companies who said the closure at the canyon is costing not only time but money – which is creating rising costs for fuel and hitting consumers in their pockets with higher food prices.

"This corridor plays a vital role in our state’s economy and for many Coloradans traveling to get to work, school, and homes along the Western Slope,” Polis said. ““As the state recovers from this incident and reopens this corridor Saturday afternoon, we will continue to need strong federal partners in the Biden administration and our federal delegation.”

Polis said he wants all lanes fixed and completely open by Thanksgiving.

Denver7 reporters Jason Gruenauer and Gary Brode contributed to this report.