Rockfall season begins as snowpack thaws

SUMMIT COUNTY — Spring is here and with that comes warm temperatures during the day and cold temperatures at night, creating the freeze-thaw effect and increasing the potential for rockfalls.

“This is a very active time of the year for rockfalls as the snow that melts during the day will freeze at night and then unthaw the next day, loosening sediment and creating rockfalls,” said Colorado Department of Transportation rockfall specialist Ty Ortiz. “Most of the time, the rockfalls are small and accidents usually occur when a vehicle hits a rock already in the road. Motorists can help prevent these kinds of accidents by paying attention to rockfall warning signs and by staying alert.”

Since rockfalls are a common incident in Summit County and pose a threat to motorists, the state transportation agencyu has a very active rockfall program, which is designed to help prevent rockslides from occurring and even rocks from hitting the roadways.

The Colorado Transportation Commission allocates $3 million for rockfall mitigation each fiscal year, which will generally allow for mitigation at three to four sites statewide.

There are two projects underway as part of the fiscal year 2008 funding:

• One project is located on Interstate 70 at Georgetown Hill and the second is on US 550 over Coal Bank Pass.

In July, the new fiscal year will begin, which will provide funding for four more projects:

• U.S. 6 at State Highway 119 in Clear Creek Canyon: Consists of scaling and installation of draped rockfall netting. The $700,000 project will begin in the fall of 2008.

• U.S. 6 Clear Creek Canyon Corridor: Consists of scaling in various locations in Clear Creek Canyon. The $650,000 project will begin in the fall of 2008.

• I-70 Georgetown Hill: Consists of the construction of hybrid rockfall fences on the slopes above Georgetown Hill. This $1.4 million project will begin in the winter of 2008.

When the program first began, CDOT received only $750,000 for mitigation statewide. Since 1999, there have been seven fatalities on Colorado Interstates or state highways as a result of rocks hitting cars and many instances of highway closures due to rockfalls.