Avalanche Forecast

A ridge of high pressure brings clear dry conditions for the week.

MONDAY NIGHT: Clear skies, light northwest wind, freezing level drops to valley bottom and alpine temperatures drop to -10 C.

TUESDAY: Mostly sunny, light northeast wind, freezing level climbs to 1800 m in the afternoon with alpine temperatures reaching -1 C.

WEDNESDAY: Mix of sun and cloud, light northeast wind, freezing level climbs to 1500 m in the afternoon with alpine temperatures reaching -3 C.

THURSDAY: Mix of sun and cloud, light east wind, freezing level climbs to 1000 m with alpine temperatures reaching -4 C.

Many wind slab avalanches were triggered on Saturday and Sunday, especially on south aspects and at treeline and alpine elevations. Most were rated as small (size 1-1.5), but a few larger (size 2.5-3) slabs were observed on southeast alpine slopes.

Avalanche activity on the surface hoar layer described in the Persistent Slab problem is starting to quiet down. Over the past two weeks, small to large (size 1-2) avalanches have released on this surface hoar layer. They have most often released between 1800 and 2300 m on northwest to east aspects.

Looking forward, daytime warming will weaken the snowpack and create the potential for loose avalanches on steep sun-exposed slopes and increase the likelihood of wind and persistent slab avalanches.

Each day rising freezing levels and the sun will potentially weaken the upper snowpack and form moist snow and crusts on sun-exposed slopes.

The upper snowpack is relatively complex. Strong northeast wind formed wind slabs in south to southwest terrain features last week. A few different layers of surface hoar and melt-freeze crust exist, which have recently acted as sliding layers. One such layer buried about a week ago may be found about 20 to 40 cm deep. The most widespread layer was buried late February and is now 60 to 80 cm deep. This layer is most commonly found in open trees (e.g. in this MIN) or sheltered terrain around the upper part of below treeline, treeline, and lower alpine elevations. This layer may only remain a concern in the north and east parts of the region.

The remainder of the snowpack is strong and well-settled.

• The more the snowpack warms-up and weakens, the more conservative you`ll want to be with your terrain selection.
• Be careful with wind slabs, especially in steep, unsupported and/or convex terrain features.
• Be aware of the potential for large avalanches due to the presence of buried surface hoar.