Avalanche Forecast
Issued: Jan 20th, 2020 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs and Persistent Slabs.
shorton,
Avalanche Canada
Use extra caution in steep and open terrain as strong wind and warming temperatures are creating unstable slabs.
Summary
Confidence
Low - Uncertainty is due to the limited number of field observations. Uncertainty is due to how the snowpack will react to the forecast weather.
Weather Forecast
MONDAY NIGHT: Partly cloudy, moderate wind from the southwest, freezing level drops to valley bottom and alpine temperatures drop to -8 C.
TUESDAY: Cloudy with light flurries in the afternoon, moderate wind from the south, alpine high temperatures around -4 C.
WEDNESDAY: Mix of sun and cloud, moderate wind from the southwest, alpine high temperatures around -4 C.
THURSDAY: Periods of snow with 5-10 cm of new snow, strong wind from the south, freezing level up to 1500 m and alpine high temperatures around -2 C.
Avalanche Summary
Several natural wind slabs were reported on a range of aspects at treeline elevations over the weekend. The most recent report of a persistent slab avalanche was last Tuesday, where a size 2 avalanche was observed on a south-facing slope at 1750 m near Crescent Spur. There have also been a number of glide cracks that failed naturally as very large avalanches in the Torpy area recently. Glide cracks are seemingly unpredictable and need to be given a wide berth. There are some great photos on the PGBCSki FB page. Mild temperatures this week could increase the sensitivity of persistent and glide slabs.
Snowpack Summary
Recent snow has settled with warm temperatures and been blown around by wind from various directions, resulting in wind slabs on all aspects at and above treeline. A weak layer of surface hoar buried in late December remains a concern. The layer has been found across much of the North Rockies region, but it has only become a problem in particular areas, such as around McBride and the McGregors/Torpy. It seems to be most prevalent in sheltered treeline features 50 to 150 cm below the surface.
Terrain and Travel
- Seek out wind sheltered terrain below treeline where you can avoid wind slabs and find great riding.
- Use ridges or ribs to avoid areas of wind loaded snow.
- Avoid steep slopes when air temperatures are warm, it is raining, or solar radiation is strong.
Problems
Wind Slabs
Recent wind from a variety of directions has formed wind slabs in places we aren't used to seeing them. Watch for wind slabs in all wind exposed terrain. Steep features near ridge crests are particularly suspect.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Persistent Slabs
A weak layer of surface hoar may be found in parts of the region. There is uncertainty on where this layer is a problem, but it appears to be of highest concern in sheltered terrain features near treeline in the southern half of the region, particularly around McBride and the McGregors.
Aspects: All aspects.
Elevations: Treeline.
Likelihood
Expected Size
Valid until: Jan 21st, 2020 4:00PM
