CDOT prepares Hwy 145 avalanche mitigation towers north of Rico for public safety readiness

After completing similar work November 14 at Highway 160 - Wolf Creek Pass, a helicopter flew to the CDOT shop north of Rico, explained Lisa Ann Schwantes, Regional Communciation Manager for CDOT Southwest Region via email correspondence to Ore Cart. Work in the Rico area was scheduled to begin at 12:00 noon, with "intermittent 30-minute closures" of Highway 145 between Rico and Lizard Head Pass, predicted a CDOT November 13 announcement. The pass re-opened to traffic at 1:30.

Five towers above two known slidepaths north of Rico were "reloaded:"

The units you saw lifted today are part of our Wyssen tower system. The towers must be "re-loaded" at the beginning of each winter season with the box units that hold the explosives/gases.

Helicopter returns to CDOT shop north of Rico after transporting equipment to one of five avalanche mitigation towers.

Ore Cart photo
November 14, 2023

Communications Manager Schwantes described remotely-controlled avalanche mitigation sites in CDOT Southwest and South Central regions.

• CO Hwy 145 north of Rico: Five towers above two known snow slide paths (Yellow Springs and Peterson). Wysenn System.
• US Hwy 50 Monarch Pass: Three units above the known Big Slide avalanche path near the Monarch Ski Area. Gazex System.
• US Hwy 550 Red Mountain Pass: Two units near the summit above two snow slide paths, Blue Point and Blue Willow. Gazex System.
• US Hwy 160 Wolf Creek Pass: Two units above the known Stud Muffin snow slide path just east of the scenic lookout area. Obellx System.
• US 550 Red Mountain Pass: Three units above the Mother Cline slide path, near the Alpine Loop access, three miles south of Ouray. Obellx System.

Ore Cart photo
November 18, 2020

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Wysenn System
Colorado Department of Transportation photo 

CDOT traditional avalance mitigation techniques still used

More traditional methods of mitigating avalanches include the following three techniques, still used across the state and our region. However, CDOT continues to move toward the advanced technologies (described above) for their safety and efficiency benefits.

• Helicopter operations - explosives are dropped by helicopter on top of the slide area
• Avalauncher guns - compressed gas is used to fire a trajectory directly at the slide path
• Howitzer guns - on loan from the U.S. Army, shoot ammunition directly at the snow slide area. - compressed gas is used to fire a trajectory directly at the slide path.

source: email communication
from CDOT - Lisa Schwantes
November 14, 2023

Ore Cart photo
November 14, 2023

Overview: CDOT avalanche mitigation

CDOT's avalanche mitigation program is very significant for public safety and important for drivers traveling along any of our high mountain passes. When large amounts of snow falls, especially in short lengths of time, the potential for avalanches grows. When snow builds up at known snow slide paths near the road, crews (with assistance from avalanche forecasters) may determine that avalanche control operations are necessary. Purposely triggered avalanches prevent large amounts of snow from building up on steep slopes and ridgelines, eliminating the risk of unexpected, natural slides from occurring at unknown times with the potential danger of snow affecting the open highway.

The general procedure includes:

• crews close the highway to the traveling public
• specially trained crews trigger the snow slide with the use of explosives
• crews use heavy equipment to clear any snow that may have fallen on the road surface
• crews re-open the highway for safe travel

The units you saw lifted today are part of our Wyssen tower system. The towers must be "re-loaded" at the beginning of each winter season with the box units that hold the explosives/gases. How they work:

• Permanently placed, mount systems (concrete bases or towers) are installed on mountains or ridgelines. The systems are loaded with units that contain cartridges of compressed air and gas. When remotely detonated, they create a concussive blast to trigger a snow slide under controlled conditions.
• The systems, when triggered, prevent large amounts of snow from accumulating on the mountains and ridgelines above the highway, which decreases the risk of unexpected, natural avalanches and long delays due to cleanup and extended safety closures.
• Remotely controlled avalanche mitigation systems allow for safer operations, more efficiency with the missions, and safer, more reliable travel conditions for motorists, reducing the duration of roadway closures.

source: email communication
from CDOT - Lisa Schwantes
November 14, 2023

more info

Helicopter Delivered CDOT Avalanche Equipment & SMPA Pole for Rico Powerline Repair
Ore Cart - November 25, 2020

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