Colorado Highway 119 in Boulder Canyon will be closed indefinitely following a major rockfall that occurred during blasting operations.
According to the Sugarloaf Fire Protection District, one of the scheduled blasts sent approximately 8,000 cubic yards of rock down the side of the mountain and onto the roadway. A blast can typically bring down about 400 cubic yards each time. This blast brought down 20 times the norm. Keep in mind that a cubic yard is roughly the size of the typical washing machine.
According to the Colorado Department of Transportation, rock blasting into the mountain will move more of the road on to bedrock so that it will fare better during the next major flood. These efforts are all a part of the CO 119 flood construction project.
In addition to this rockfall, CDOT geotech officials have also found another area of loosened rock that will require additional blasting activities.
The highway will remain closed for at least the next 24 hours. Detours are in place using Colorado Highway 72 to bypass this area. Clearing efforts will continue throughout the night to ensure the roadway is safe and clear for regular traffic as soon as possible. No one was injured in this rockfall.
The local school district and RTD Denver are working on plans to temporarily replace routes impacted by the rockfall.
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While this rockslide was due to intentional blasting, rockslides and mudslides are relatively common in Colorado. They tend to occur most frequently during changing seasons, often due to hard rain fall and melting snow. While you’re driving through steep terrain where loose rock might be present, watch for warning signs of rockslides, including smaller rocks, dirt, and pebbles dropping onto the roadway from above.
Several rockslides and mudslides have occurred recently in Colorado, including one that destroyed part of a highway and another that covered I-70 in mud. It’s also worth mentioning that a rockslide occurred on CO 119 in July, temporarily closing a portion of the road.