Avalanche Forecast
Issued: Dec 15th, 2013 8:29AM
The alpine rating is Storm Slabs.
, the treeline rating is , and the below treeline rating is Known problems includeSummary
Confidence
Fair - Due to the number of field observations
Weather Forecast
Tonight and Monday: Westerly onshore flow will continue with strong westerly winds and light precipitation. Freezing levels hovering around 600m.Tuesday: Another large storm hits the Northwest with heavy precipitation and strong southwest winds. Freezing levels may spike again as the storm passes through.Wednesday: Pacific frontal system exits the area and moves off to the east. Freezing levels drop to valley bottom for most of the forecast area through the next few days as arctic air moves south.
Avalanche Summary
Numerous size 2-3 avalanches have been observed in the bear pass area. These mainly occurred on north through east slopes that are lee to strong southwest winds.The warm new snow is likely not bonding well to the weak layers formed in early december. Heightened avalanche activity and conditions will continue through Monday. Lower elevations are experiencing moist or wet natural avalanches releasing at or near the ground. This will become less of a problem once the freezing levels start descending back down to valley bottoms. Lee slopes will be touchy at upper elevations until this storm snow gets a chance to bond.
Snowpack Summary
A mixture of heavy rain/snow/wet snow has fallen to 1500m elevation. Strong Southwest winds are transporting snow and developing deep pockets that are sitting above recent weak surface layers. Rising temperatures during the storm have likely developed a relatively warm storm slab above a cold layer of wind crusts, surface hoar and surface facets, an upside down scenario. This layer was buried anywhere from 30-50cm prior to the major Dec 14 storm.Earlier in the week, reports from the Shames area at 950m elevation suggested the mid and lower snowpack was composed of various faceted layers and a stiff 4 cm crust. Another crust can be found closer to the base of the snowpack. The recent precipitation will strengthen the snowpack at lower elevations, but may prove to be problematic with rapid wind loading at upper levels.
Problems
Storm Slabs
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Dec 16th, 2013 2:00PM