Located in the Vail/Summit county backcountry forecast zone and in a continental climate, the Big POW backcountry zone typically gets the most significant snow accumulations from NorthWesterly storms. Though all of our terrain will be mitigated for avalanche danger, we highly recommend carrying your PPE with you at all times. There will be two permanent closures as seen in the Trail map for the convenience of our guests. These areas are either trees that are too dense to ski safely or a flat area where guests could easily get stuck.
Avalanches in Vail/Summit County since Jan.1 2010:
Avalanche Terrain
Our avalanche terrain will be classified with two types of maps as outlined in TASARM. We will be classifying our entire permit zone using the ATES, Avalanche Terrain Exposure Scale, (Statham et al., 2006) as our Hazard, Risk, and Terrain Classification Map and further mapping out our complex terrain with an Avalanche Path map as outlined in TASARM. The reason for multiple mapping classifications being the numerous isolated terrain features in our zone, many of which do not have distinct avalanche paths but could potentially produce a D2 avalanche, and the more obvious larger avalanche hazard zones, the complex terrain, will be further identified with a specific avalanche path map.
For the Avalanche Path Map, starting zones and tracks are calculated using terrain statistics, slope angle, substrate, and terrain features. Runout zones estimated using an alpha angle of 22 degrees(+/- 1 degree), the average alpha angle in Colorado calculated from 130 avalanche paths (Mears, 1988). Natural terrain features capable of redirecting or stopping avalanche debris such as rock outcroppings, gulleys, trees, or other terrain traps are also key factors used to estimate runout distances.
Our primary concern with Avalanches is terrain steeper than 30 degrees capable of producing a D2 avalanche or greater. These terrain criteria are mostly confined to the Cirque Wall. There are many other features capable of producing less than or equal a D2 avalanche that will still be mitigated and mapped out in the ATES map as complex or complicated terrain. Smaller, more isolated terrain features capable of producing less than a D2 avalanche may be excluded from the map as these isolated features are too difficult to map out at this scale.