Avalanches in the San Juan Region

The San Juan Mountain region is prone to avalanches due to several aspects of the area's topography and snowfall pattern. The snow in the area is relatively unstable due to the warm daytime sun, cold nighttime temperatures, and steep terrain. In addition the formation of this weak layer early in the season allows for avalanches to occur. This is why the San Juan Mountain region is a perfect area for avalanches. 

The snowfall pattern is a major contributing factor to avalanches. A typical winter season in the San Juan region is comprised of snowfall early in the year that remains on north-facing aspects, such as Spiral Staircase and Plunge off of chair 9. This early season snow is unstable because of the generally warm temperatures during the day that cause the snow to become shallow. The cold nighttime temperatures alter the snow's make-up even more and cause it to form fine grains called "sugar snow". The "sugar snow" lacks cohesiveness and thus it is unstable, especially when additional snow is packed on top of it.