Avalanche Forecast

Moderate - Forecast snowfall amounts are uncertain

Sunday: Cloudy with flurries bringing approximately 15 cm of new snow, continuing overnight. Light to moderate west winds. Freezing level to 1100 metres with alpine high temperatures around -6.Monday: Mainly cloudy with scattered flurries bringing 5-10 cm of new snow. Light west winds. Freezing level around 1000 metres with alpine high temperatures of -7.Tuesday: Cloudy with scattered flurries bringing 5-10 cm of new snow. Light to moderate west winds. Freezing level around 1300 metres with alpine high temperatures of -4.

Reports from Friday showed new storm slabs becoming touchy and producing numerous natural, remotely triggered, and ski cut releases generally from size 1-2.5. Crown depths ranged from 10-30 cm deep. One size 1.5 persistent slab was reported to have run on the mid January weak layer down about 100 cm.On Thursday, both natural and human triggered avalanches to size 1.5 were triggered on north and northeast facing slopes above 1700 m. A rather spooky size 2.5 persistent slab avalanche was triggered by a professional releasing a cornice onto a north facing slope at 1900 m. Reports from Wednesday included an observation of a size 2.5 wind slab triggering remotely from 300 metres away on a low angle slope at 2300 metres. Elsewhere, storm slabs were observed running naturally and with explosives from size 1.5-3. Explosives control in the adjacent North Columbias yielded numerous persistent Slab results from size 2-3.5 on all aspects at all elevations. The deep mid-December layer and an even deeper layer from November were both frequent failure planes. The mid December layer is also suspected in two natural size 4 releases in and near the Glacier National Park area.

About 30 cm of new snow fell over Thursday and Friday. This rests on up to a meter of storm snow from last week which has settled into a slab aided by a warming event on Monday the 29th and strong to extreme southerly winds on January 29th and 30th. This recent snow overlies three active weak layers that are now buried deeply in our snowpack:1) 70 to 140 cm of snow now sits on the crust and/or surface hoar layer from mid-January. The crust is reportedly widespread, with the possible exception of high elevation north aspects. The surface hoar is 5 to 20 mm in size and was reported at tree line elevations and possibly higher. This layer is the primary weak layer of concern in the South Columbias and remains well within the range of human triggering.2) Deeper in the snowpack, the early-January persistent weak layer is 130 to 175 cm below the surface. It is composed of surface hoar on sheltered slopes as well as sun crust on steep solar aspects and is found at all elevation bands. 3) Another weak layer buried mid-December consisting of a facet/surface hoar/crust combination is buried up to 200 cm below the surface. It is most problematic at and below tree line.