Avalanche Forecast

An upper ridge parked over the west coast will lead to dry and very warm weather this week.  Freezing levels should climb to 12000 and 13000 feet Wednesday and Thursday.  Winds are generally forecast to be on the lighter side during this stretch.  A cooling trend will begin Thursday night and Friday as cooler onshore flow develops and the upper level ridge shifts east. Further cooling and unsettled weather will be seen over the weekend as a cool upper low moves over the area. 

Wet loose, cornice failures and isolated wet slabs above treeline near and west of the Cascade crest and Mt. Hood will be the primary avalanche concerns through Thursday.  As freezing levels rise through mid-week, look for heavy recent snow received at higher elevations to become more likely to avalanche. Less avalanche activity is expected east of the Cascade crest and at lower elevations.  

Wet snow deeper than a few inches, pinwheels and small natural wet loose avalanches usually precede larger wet loose snow avalanches. Wet loose avalanches should mainly stay within the most recent snowfall but we can't rule out large or very large avalanches entraining wet snow below. Avoid steeper slopes during peak heating, give cornices a wide berth and be wary of terrain traps where even a small but powerful wet loose avalanche can become deep very quickly. 

About 1 to over 2 feet of snow accumulated along the west slopes of the Cascades and Mt. Hood above about 5000 to 6000 feet late last week. From last Thursday through Saturday morning, 8-10 May, 1.5 inches of water was recorded at Mt. Baker and Snoqualmie Pass, 2-2.5 inches at Crystal and Paradise, and 3.5-5.5 inches at stations on Mt. Hood! Less precipitation fell at Hurricane Ridge, east of Cascade crest, and at lower elevations in general.  

Natural and skier triggered wet loose slides were common on Sunday, even on non-solar slopes above treeline.  Most were point release wet loose avalanches that entrained new snow. But one shallow (D1) wet slab was skier triggered in the Mountain Loop area Sunday illustrating that isolated slabs are still possible. Brisk easterly winds near the Cascade crest Monday helped locally mitigate the wet loose avalanche likelihood. However, ski cuts produced wet loose avalanches up to size 2 on solar slopes above 5000 feet at Chinook Pass Monday. Washington Pass DOT reported only small wet loose slides in the Washington Pass area Tuesday.