Avalanche Forecast
Issued: Mar 19th, 2016 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Loose Wet, Persistent Slabs and Cornices.
tim haggarty,
Avalanche Canada
Watch for warming to increase the potential for skier triggered and natural loose wet avalanches and cornice failures. With the potential for triggering the persistent layers be conservative with your exposure to avalanche terrain through Monday.
Summary
Weather Forecast
Despite mainly clear skies Saturday, light winds prevented freezing levels from breaking treeline. We expect freezing levels to reach treeline by mid day Sunday and stay there as a warm SW flow brings moist air. Light precip (rain?) is expected with a poor overnight recovery as winds shift to West and increase to moderate at treeline into Monday.
Snowpack Summary
Solar crusts on 40-60cm of recent snow overlies a well settled mid and lower pack. Observations are limited but we suspect there are buried sun crusts on steep E through W aspects with 60-100cm above (similar to Banff region). Isolated thin snowpack areas have weaker facet layers, but this is not a widespread snowpack characteristic of the region.
Avalanche Summary
Avalanche control on Mts. Stephen and Dennis Friday produced avalanches to size 3, one of which slid to ground in a steep, thin snowpack area. That flight saw numerous slides to size 3 mainly along and East of the divide where the basal weak layers are more prevalent. These were on N- NE aspects in the alpine in the previous 24-48 hours.
Confidence
Problems
Loose Wet
Expect loose wet avalanches at low elevations and on solar aspects with inversion conditions and a poor overnight recovery into Monday with the chance of rain. Loose wet avalanches may trigger persistent slabs where buried crusts exist.
- Minimize exposure to steep, sun exposed slopes when the solar radiation is strong.
Aspects: North, North East, East, South East, South.
Elevations: All elevations.
Likelihood
Expected Size
Persistent Slabs
Now that the sun is higher in the sky, buried crusts becomes more of a problem. Presently there are several crusts buried on S through E and W aspects, with 50-100 cm overlying them. We do not have many observations of this currently.
- Dig down to find and test weak layers before committing to a line.
Aspects: North, North East, East, South East, South.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Cornices
There are large cornices at this point in the season. With warming expected do not expose yourself to this hazard or the avalanches they may trigger.
- Cornices become weak with daytime heating, so travel early on exposed slopes.
Aspects: North, North East, East, South East, South.
Elevations: Alpine.
Likelihood
Expected Size
Valid until: Mar 20th, 2016 4:00PM
