Avalanche Forecast

Fair - Forecast snowfall amounts are uncertain on Wednesday

Synopsis: A frontal system is spreading moderate snowfall to the region today and through Wednesday. Conditions remain unsettled in the wake of the system on Thursday before high pressure develops on Friday resulting in sunshine.  Tonight and Wednesday: 10-15 cm (maybe more near Bear Pass). The freezing level is around 400-500 m. Winds ease to moderate from the southwest, shifting to northwest.  Thursday: Mainly cloudy with a chance of flurries. The freezing level drops to valley bottom and winds ease to moderate from the west. Friday: Mainly sunny. Temperatures remain cool with the freezing level at valley bottom. Overnight lows near treeline could be in the -15 range. Watch for outflow winds to develop.

Natural, human triggered, and remotely triggered avalanches up to size 2 continued on Monday with most avalanches releasing on the March 9th layer. A very large (size 3.5) avalanche was triggered in Cherry Bowl in the Shames backcountry on Sunday. Click here for a full report. This slide illustrates clearly the potential for deep and destructive releases on the March 9th surface hoar layer. On Saturday, natural slab avalanches were reported up to size 3 on all aspects in the alpine.

30-60 cm of recent storm snow rests on a variety of old snow surfaces, including crusts, previous wind slabs and surface hoar. Warmer temperatures and recent strong southwest winds have now set this new snow into a reactive slab, with wind slabs building in exposed lee areas. The surface hoar (buried March 9th) is reported to be well-developed and fairly widespread, at treeline and alpine elevations. Recent snowpack tests have produced sudden failures with moderate loading force at this interface. The mid snowpack is generally well settled and strong. Cornices are large and untrustworthy, especially when the sun is out.