Snowfall totals since Thursday at noon are 19 to 22 inches in the mountains with about 1.5 inches of moisture and 14 inches in the valleys. Temperatures warmed during the storm and created an upside down storm snow density profile. This new snow fell upon older snow that was subjected to three days of bitter cold temperatures that caused those old snow crystals to facet and weaken. Strong southwest wind accompanied this snowfall. Be aware that avalanche mitigation efforts have not been conducted at the local ski resorts.
At the mid and upper elevations southwest winds have created wind slabs up to two feet in depth. These slabs could be triggered by the weight of a single person and are most likely to be triggered on steep northerly aspects above an elevation of 9,000 feet. Steep, wind loaded, active avalanche starting zones on other aspects at the mid and upper elevations are also suspect.
It will be cold with clear skies tonight. Temperatures will be below zero but not as cold as they were several nights ago. On Sunday skies will be mostly sunny with areas of morning valley fog. Morning low temperatures will be inverted, with the coldest valley locations in the negative teens, and in the mountains in the negative single digits. Daytime highs will rise above zero into the single digits and teens. Winds at 10,500 feet will be from the north tonight at 10-20 miles per hour with higher gusts. Daytime winds will decrease to 5-10 miles per hour and back towards the northwest.The general avalanche hazard is expected to be MODERATE at the higher elevations on Sunday and LOW at the mid and lower elevations. Human triggered slab avalanches up to two feet in depth are possible, especially on steep north facing aspects above an elevation of 9,000 feet. Steep wind loaded avalanche starting zones at the mid elevations may also be suspect in isolated areas. Avalanches are unlikely at the lower elevations.
