Colorado Avalanche Information Center is not messing around when it says that, “Reports of natural avalanches running in all possible paths continue to stream in.” The currant avalanche threat in Vail and Summit Counties are at high to extreme. That is just about as bad as it can get.
Extreme (level 5 of 5) danger. Reports of natural avalanches running in all possible paths continue to stream in. Historic avalanches have been observed or triggered all week and will continue throughout the day. A second round of heavy snowfall and strong winds have created very unusual and extremely dangerous avalanche conditions. Natural avalanches have the potential to break widely across mountain faces and run down to the valley floor. Travel in, near, or below avalanche terrain is not recommended. This may include backcountry roads, trailheads, or any infrastructure below avalanche paths where avalanche mitigation is not occurring. Even low elevation avalanche terrain that rarely slides might today.
Reports coming in from our highway forecasters traveling on roadways early this morning or doing mitigation work have stated: “there isn’t a piece of avalanche terrain that hasn’t slid.” This is incredible, but shocking news given the impressive avalanche cycle over the past few days. This second round of heavy snowfall has put storm totals for March into historic levels. Combine these amounts with strong winds and we have some of the most dangerous avalanche conditions in years. Crews are out to keep the major roadways open, but further travel in or around avalanche terrain is not recommended. Even at lower elevations, a high rain line has increased the risk of wet avalanches. Under these exceptional conditions, expect all avalanche paths, both small and large to slide.
Some of the recent avalanches were really big, some reaching historic levels. Tuesday, both natural and explosive triggered avalanches reached D3 to D4 in size. The Disney slide path above Highway 40, as just one example, hasn’t run this big since 1957. The D4 avalanche out of Bethel on the east side of the Eisenhower Tunnel crossed all 4 lanes of I-70 with debris 6 to 15 feet deep for a 300 foot long stretch of road.
This gives you an indication how avalanches have grown larger and larger with each big loading event. We are seeing the biggest avalanches of the season, and in some cases the avalanches are running as big as they have in decades. Some very big slides from Jones Pass, to Breckenridge, to Fremont Pass is just a small sample illustrating that the concern is widepread across the Front Range and Vail-Summit zones.
In Steamboat, the avalanche conditions are not quite as extreme, but all aspects and elevations are dangerous and any slope over 30 degrees should be avoided. With high amounts of uncertainty in wet snow, heavy loads, and continued drifting, it’s best to steer clear of avalanche terrain until the snowpack can adjust.