Rockfall Work Continues on US 550, Red Mountain Pass - Extended Work Hours

May 18, 2012 - PROJECT UPDATE - Southwestern Colorado/CDOT Region 5 - OURAY COUNTY – The Colorado Department of Transportation continues work on a project to reduce the potential for rockfall on US 550 on Red Mountain Pass south of Ouray, between the Bear Creek Tunnel and the snow shed (mile marker 91).

The project will be completed by June 15, 2012. In addition to the rockfall mitigation, crews are making repairs to a crib wall (a retaining wall below the highway) under the southbound lane at mile point 89.6, approximately 1.5 miles north of snowshed.

The safety improvement project, contracted to Midwest Rockfall, Inc., of Denver for $845,880 (rockfall work) and $591,201 (retaining wall repairs), involves the following:

  1. Rockfall reduction measures between mile posts 88 and 91

a)    minor rock scaling - rocks will be brought down with pry-bars or inflatable bags;

b)    rock stabilization -  crews will drill 1 3/8”-diameter holes (approximately 20 feet apart) down to fracture points, then fill holes with a Poly-Urethane Resin, which acts as a kind of glue;

c)    rock bolting - crews will drill and insert 10-foot-long steel dowels and 25-foot long steel rock bolts into various locations to provide further stabilization;

d)    rockfall netting - several types of rockfall wire mesh/netting will be anchored from above to guide smaller rocks into ditch below.

  1. Retaining wall repairs and pipe replacement at mile post 89.5.

a)    excavate for pipe replacement;

b)    replace pipe and place new inlet;

c)    install new retaining wall.

CURRENT TRAVEL IMPACTS: There will be no work on Friday May 25th through Tuesday 29th due to the Memorial Day holiday weekend. Work will resume on Wednesday May 30th. Throughout the duration of the project motorists will encounter single-lane, alternating traffic between 7 AM and 6 PM on the northbound lane Monday through Friday. There will be no weekend work. Motorists will also encounter full traffic holds of up to 20 minutes during work hours. Please note, while these traffic holds will be limited to 20 minutes or less, motorists’ actual delays may exceed 20 minutes, as the traffic queues are cleared in each direction. Delay times will vary depending upon traffic volumes.  (Access for emergency vehicles through the work area is planned for.) Night closures from 8 p.m. to 6 a.m. (weekdays only) will be necessary later on in the project. Notice will be sent before that occurs.

SIGN UP FOR PROJECT INFORMATION: For information on this project, the public may call Midwest Rockfall, Inc.’s Public Information Line at (970) 462-1529. Please also sign up to receive FREE highway information updates for this area and others by going to CDOT’s web site – and choosing the green cell phone icon on the upper right corner. For information on other CDOT projects statewide, the public may log on to or call 511. Thank you for going Slow for the Cone Zone!

*CDOT’s Rockfall Program

The Colorado Rockfall Hazard Rating System (CRHRS) sites are ordered in funding priority from 1, which has the highest combination of hazard and risk, to 756 which has the lowest. To determine which sites are of high priority, several factors are analyzed including slope profile, geological characteristics and traffic data.

The rockfall program, started in 1996, was created to track rockfall information, implement a rating system and mitigate potential hazardous areas.  When the program first began, CDOT received just $750,000 for projects statewide. Since that time, funding for the Rockfall Program steadily increased to accommodate rising construction costs and allow for additional mitigation across the state. In recent years, the program was receiving $3 to $5 million per year. For the 2012-13 season, the program is receiving about $7 million—which includes $2 million in State Transportation Commission contingency funds that will help supplement projects statewide.

Since the program began, about 70 sites have been mitigated through CDOT’s Rockfall Program.  CDOT rockfall specialists also provide additional assistance at nearly 30-40 locations statewide each year in response to rockfall and other activity.