Avalanche Forecast
Issued: Mar 25th, 2023 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs, Persistent Slabs and Loose Wet.
jpercival,
Avalanche Canada
As temperatures warm and the sun appears, make travel choices that avoid steep south aspect terrain and large overhead triggers such as cornices.
Watch for lingering wind slabs that may remain reactive to human triggering.
Summary
Confidence
Avalanche Summary
On Friday, a few small (size 1) wet slab avalanches were observed on a North east aspect. All other operations did not observe any new avalanche activity.
On Thursday , avalanche activity continues to subside with activity only occurring below tree line, one large (size 2.5) glide slab on known steep rock slab features and a few large (size 2) loose wet avalanches.
On Wednesday, avalanche activity had begun to subside as only a few small (size 1) loose wet avalanche were reported that had initiated from very steep south aspect terrain at treeline elevations and below.
During last weekend, two natural size 3 persistent slab avalanches were observed. Both these avalanches ran to valley bottom and are suspected to have released on a weak layer of surface hoar. Two, size 1.5 persistent slab avalanches were remotely triggered by a helicopter on the same layer.
Snowpack Summary
2 cm of new snow has bonded to a well settled upper snowpack. Below 1800m on all aspects a MFcr is present and on south aspects it extends up to 2000 m.
At elevations treeline and below, a weak layer of rounding surface hoar is found 20-50 cm down in sheltered terrain and continues to be reactive to skier traffic.
A second weak layer of surface hoar and/or faceted grains may be found about 60 cm deep, particularly on shaded aspects near treeline.
The lower snowpack presents as consolidated and strong.
Weather Summary
Saturday Night
Clearing in the early am, no new precipitation. Light northwest winds at ridgetop. Treeline temperature -8°C. Freezing levels descending to sea level.
Sunday
A mix of sun and cloud, no new precipitation. Light east winds at ridgetop. Treeline temperature -4°C. Freezing levels 1000 m.
Monday
A mix of sun and cloud, no new precipitation. Light southeast winds at ridgetop. Treeline temperature -4°C. Freezing levels 1000 m.
Tuesday
A mix of sun and cloud, no new precipitation. Light southeast winds at ridgetop. Treeline temperature -4°C. Freezing levels 1000 m.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Be carefull around freshly wind loaded features.
- Carefully assess open slopes and convex rolls where buried surface hoar may be preserved.
- Potential for wide propagation exists, fresh slabs may rest on surface hoar, facets and/or crust.
- Extra caution for areas experiencing rapidly warming temperatures for the first time.
Problems
Wind Slabs
Both south and north winds have redistributed new and available snow into fresh wind slabs in exposed lee terrain features at higher elevations. A buried layer of surface hoar is increasing the reactivity and propagation of wind slabs.
Aspects: North, North East, East, South East, South, North West.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Persistent Slabs
A weak layer of large surface hoar is found down 20-50 cm. This layer has been most active in the Shames region however with additional load we may see wider spread reactivity on this layer. Use caution on sheltered and shaded slopes where surface hoar is more likely to be preserved.
Aspects: North, North East, East, West, North West.
Elevations: All elevations.
Likelihood
Expected Size
Loose Wet
When temperatures rise and the sun appears expect on steep south aspect terrain that a natural wet loose avalanche cycle will occur. Even small wet loose avalanches can push a skier in a terrain trap such as a cliff or gulley feature.
Aspects: East, South East, South, South West, West.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Mar 26th, 2023 4:00PM
