Rockfall in the Rockies: snow totals, wet spring contribute to this year's rock instability
A part of driving around our lovely state is the need to be aware a big ol' rock could come tumbling down on top of you at any moment if the perfect conditions exist. A lot of that plays into steep grades on rock walls nearby highways and interstates, like I-70, but a big chunk of it also revolves around moisture and the effect it has on our rocks.
This year parts of Colorado saw snow totals they haven't seen in years, namely the southwest portions of Colorado. All that moisture, mixed in with our very recent rain/snow events in spring are leading Colorado Department of Transportation crews to stay extra vigilant on making sure our roadways are safe for drivers, rumbling past rockfaces, now with runoff sliding down them.
Elementary school science explained to us erosion, or water running past rocks and dirt for long periods of time leading to it chipping away at the stability, but up in the higher elevations, a freeze/thaw cycle will also work to break loose rocks, like little, tiny ice pickaxes pushing their way into microscopic cracks in solid rock.
It's likely what lead to this big boulder, which Lisa Schwantes, CDOT spokesperson for the southwest region, estimates is about the size of a VW bug. It took a construction vehicle to remove the boulder just north of Telluride, but crews with CDOT are hoping to stop those kinds of things before they come to fruition with operations like rock scaling.
"Rock scaling would entail a team of pretty brave souls that will scale themselves up along a cliff," Schwantes said. "First they check it out, they see if there's any loose rock. They see if there is any potential of rock coming down, and after that inspection is done, then they help us determine whether or not we need to get in there and actually do more preventative work."
That preventative work can get a lot more aggressive than just pulling on loose rocks like you would a loose tooth.
"Maybe placing dynamite behind some crevices so that we can blast that rock that had the potential of coming down," Schwantes said, with a grin.
With the widespread threat of rockfall danger in Colorado, and the potentially extended period of time runoff will be a factor thanks to more snowfall this year than last, CDOT said it's as important as ever to keep eyes on the road and make sure you can respond quickly should conditions change.
"It can be along any roadway in Colorado that has a cliff face right adjacent to it," Schwantes said. "You get that freeze-thaw phenomenon... that just happens over and over again until it loosens the rock and it falls onto the roadway. So just the moral of the story is be alert, be aware of your surroundings all the time."
