An intense storm on Wednesday produced very touchy avalanche conditions with both natural and human triggered avalanches. Today Storm Slabs and Persistent Slabs will be the most dangerous avalanche problems. Watch for avalanches breaking at or below the old snow surface. Slides that break into old snow layers will be both large and dangerous.
The avalanche danger in the Southern San Juan zone is CONSIDERABLE (Level 3) near and above treeline and MODERATE (Level 2) below.
The new snow from the last storm fell on a variety of weak, surface-snow layers and quickly overloaded the new/old snow interface. Reports of natural avalanches are still rolling into the office. Most of these avalanches were large enough to kill a backcountry traveler, some with fracture lines several hundred feet wide. Although the chance of a natural avalanche is decreasing, you can still trigger one of these Storm Slab avalanches today. Slopes steeper than about 35 degrees, and near and above treeline areas are the most dangerous.Deeper weak layers and Persistent Slab avalanches remain a problem at all elevations on northwest through north and east aspects. Avalanche workers triggered several avalanches that broke into these layers Silverton and Ouray and near Wolf Creek Pass over the last two days. Most of these avalanches released on northwest, north, and east facing slopes that were near or above treeline.
Arctic air in a broad low-pressure trough is keeping the temperatures unseasonably cold across Colorado. Today a weak disturbance will move through the state bringing clouds to most mountain areas and the odd snow shower to the high peaks. Upper-level winds increase during the day as the flow backs to the west, but with cold air entrenched in the valleys they’ll probably remain at crest level. Overnight low temperatures will be below zero for at least one more night. A stronger system moves into the state on Saturday. Snowfall will begin in the northwest corner Saturday morning and spread through the mountains during the day. Snow should continue Saturday night and taper off on Sunday. This system should favor the Southern Mountains with storm totals in excess of a foot by the end of the weekend.