Sustained warm temperatures and sun are forecast to continue this week. Large cornices are likely weakening and loose wet avalanches become increasingly likely as the surface crust breaks down, especially on steep sun exposed slopes.
Summary
Confidence
Moderate - Uncertainty is due to the limited number of field observations.
Weather Forecast
The region now sits under a warm ridge of high pressure which is expected to persist through the week bringing high freezing levels and sun.
Monday night: Clear, light NW wind, freezing levels 2000-2400 m.
Tuesday: A mix of sun and cloud, light NW wind, freezing levels around 2400 m.
Wednesday: Sunny, light NW wind, freezing levels around 2500 m.
Thursday: Sunny, light SW wind, freezing levels around 2600 m.Â
Avalanche Summary
No new avalanche activity has been reported over the last few days. Last Thursday, glide cracks were reported to be growing in size, likely from the persistent warm temperatures and rain event.Â
If you head out into the mountains, please share any observations or photos on the Mountain Information Network.
Snowpack Summary
The warm temperatures are slowly starting to melt a thick crust that reaches to mountain top. Below the crust, the snow is moist down 50-100 cm where several old crust are now breaking down. At the highest elevations around Squamish, you may find up to 15 cm of new snow from the recent storm.Â
Around 150 to 200 cm deep, weak faceted grains may sit above a melt freeze crust that formed during the cold spell in late December. Reports suggest that the snowpack has been bonding well to these layers. The middle and base of the snowpack are strong, consisting of well-bonded snow and various hard melt-freeze crusts.
Terrain and Travel
- Avoid steep slopes when air temperatures are warm, or solar radiation is strong.
- The more the snow feels like a slurpy, the more likely loose wet avalanches will become.
- Cornices become weak with daytime heating or solar exposure.
- Even small cornices may have enough mass to be destructive and deadly.
Problems
Cornices
Large cornices around ridge crests are expected to become weak during the warming event this weekend. With each day of warming, cornice failures will become more likely.
Aspects: North, North East, East, North West.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Loose Wet
As the warm conditions and sun persist, loose wet avalanches will become more likely on sun exposed slopes. Extra caution is necessary around steep south facing slopes when the sun is strong.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Jan 25th, 2022 4:00PM
