Avalanche Forecast
Issued: Feb 2nd, 2019 4:38PM
The alpine rating is Storm Slabs, Persistent Slabs and Deep Persistent Slabs.
, the treeline rating is , and the below treeline rating is Known problems includeSummary
Confidence
Moderate -
Weather Forecast
SATURDAY NIGHT - Mainly cloudy with isolated flurries / southerly winds, 10-25 km/h / alpine low temperature near -18SUNDAY - Mainly cloudy with isolated flurries,2-4 cm / southeast winds 10-25 km/h / alpine high temperature near -18MONDAY - A mix of sun and cloud / northeast winds 10 km/h / alpine high temperature near -17TUESDAY - Mainly sunny / northeast winds, 10-15 km/h / alpine high temperature near -13
Avalanche Summary
Avalanche activity continued on Saturday with reports of numerous natural avalanches to size 3.5, as well as explosives triggered avalanches to size 2.5, and human triggered avalanches to size 1.A widespread natural avalanche cycle to size 3 was reported on Friday. There were also several human triggered avalanches to size 1.5 reported in the region on Friday. Some of these reportedly failed on a persistent weak layer that was buried in mid January. This MIN report illustrates how reactive the new snow was on Friday.On Thursday, a few natural and human triggered avalanches to size 1.5 were reported on all aspects around treeline. These also reportedly failed on the persistent weak layer that was buried in mid January.There is a great MIN report from January 22nd that shows a natural avalanche (size 3.5) in International Basin, on the deep persistent layer. Check it out here. While this is an old observation, it is relevant as this layer is still lurking, and may catch people off guard.
Snowpack Summary
20-55 cm of new snow has fallen in the region since Thursday. This new snow sits on wind slab, surface hoar (feathery crystals), facets (sugary snow) and a crust on sun-exposed slopes. A persistent weak layer that was buried in mid January is now buried approximately 30-80 cm. This layer consists primarily of surface hoar, however there is also a crust associated with it on sun-exposed slopes. This layer has been most reactive at treeline and below.The base of the snowpack has a deep persistent weak layer near the ground. This layer consists of facets over a crust. This weak interface continues to produce large and destructive avalanches that are sporadic in nature, and very difficult to predict. This layer is most likely to be triggered from areas where the snowpack is shallow and weak. Rocky alpine bowls, ridge crests and rocky outcroppings are some examples of the kind of terrain to be wary of.
Problems
Storm Slabs
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Persistent Slabs
Aspects: All aspects.
Elevations: Treeline, Below Treeline.
Likelihood
Expected Size
Deep Persistent Slabs
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Feb 3rd, 2019 2:00PM