Avalanche Forecast
Issued: Mar 24th, 2021 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Storm Slabs.
shorton,
Avalanche Canada
Human triggered avalanches are possible on steep open slopes where recent snow has formed slabs. However, in many areas the snow remains loose.
Summary
Confidence
Weather Forecast
WEDNESDAY NIGHT: Cloudy with some light flurries and trace accumulations, 20 km/h northwest wind, treeline temperatures drop to -6 C.
THURSDAY: Mix of sun and cloud with some light flurries but no notable accumulations of snow, 20-30 km/h northwest wind, freezing level reaches 1600 m with treeline temperatures up to -3 C.
FRIDAY: Mix of sun and cloud with some light flurries but no notable accumulations of snow, 20-30 km/h west wind, treeline temperatures around -3 C.
SATURDAY: Mix of sun and cloud, 20-40 km/h southwest wind, freezing level climbing to 1900 m, treeline temperatures around -1 C.
Avalanche Summary
There was a spike of avalanche activity on Monday with a storm resulting in several natural slab avalanches on south, east, and north facing slopes (mostly size 1.5-2). These slabs were also reactive to humans on Monday and Tuesday, resulting in size 1-2 slab avalanches that were mostly 30 to 40 cm thick (illustrated by this snowboard triggered avalanche just south of Revelstoke and this snowmobile triggered avalanche just north of Revelstoke). In many areas the snow had not developed a slab, but still produced natural and human triggered dry loose avalanches in steep terrain (size 1-1.5). A few cornice failures were also reported on Monday.
Snowpack Summary
10-15 cm of fresh snow sits above sun crusts on solar aspects and small surface hoar on north-facing slopes. Over the past week 30-50 cm has accumulated above an interface that formed during the mid-March dry spell, which consists of a widespread crust (except on north-facing slopes above 1800 m). In some terrain (primarily wind affected terrain) this snow had settled into a slab, however in many areas this snow remains loose. Large cornices loom over alpine ridgetops. Spring temperatures and sun are producing a melt-freeze snowpack below 1500 m and higher on solar slopes. The lower snowpack is strong.
Terrain and Travel
- Avoid areas where the snow feels stiff and/or slabby.
- Be careful with open slopes and convex rolls, especially in more extreme terrain.
- Use ridges or ribs to avoid areas of wind loaded snow.
- Pay attention to cornices and give them a wide berth when traveling on or below ridges.
Problems
Storm Slabs
30-50 cm of recent snowfall has potential to form reactive slabs on some steep terrain features. The most likely spot to find reactive slabs is where there has been additional wind loading in lee terrain. There are also some surface hoar and crust layers in the upper snowpack, and while none of these layers are overly concerning, they may act as sliding layers for storm slabs.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Mar 25th, 2021 4:00PM
