Avalanche Forecast
Issued: Mar 16th, 2020 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Loose Wet, Cornices and Wind Slabs.
shorton,
Avalanche Canada
Avalanches will become more likely as the snow heats up, especially on slopes getting hit by the sun.
Summary
Confidence
High - Uncertainty is due to rapidly fluctuating freezing levels.
Weather Forecast
A ridge of high pressure brings clear dry conditions for the week.
MONDAY NIGHT: Clear, light northwest wind, freezing level drops from 2300 m to 1700 m overnight with mountain top temperatures staying above freezing.
TUESDAY: Mostly sunny, light northeast wind, treeline temperatures around +3 C, freezing level around 1700 m.
WEDNESDAY: Sunny, light northeast wind, treeline temperature around +3 C, freezing level around 1500 m.
THURSDAY: Mostly sunny, calm, treeline temperature around +3 C, freezing level around 1500 m.
Avalanche Summary
Over the weekend a few wind slab avalanches were human triggered, including a size 2 slab on a northeast slope on Brunswick Mtn, a size 1 slab on a west slope on the Lions, and a size 1 slab on a southeast slope in Tetrahedron.
Looking forward, loose wet avalanche activity and cornice falls could be triggered with the ongoing warming trend. The potential of triggering wind slab avalanches remains possible in steep alpine terrain.
Snowpack Summary
Surface conditions are highly variable with a mix of crusts, moist snow, and hard wind slabs. The warm air coupled with strong radiation from the sun has potential to rapidly weaken the snowpack and cornices.
In the alpine, hard wind slabs may be found on all aspects due to variable wind directions. In sheltered terrain, about 30 cm of settled snow may overly a melt-freeze crust and potentially small surface hoar crystals. The remainder of the snowpack is well-settled. The snowpack depth varies from around 300-400 cm around 1200 to 1400 m and tapers rapidly with elevation, with no snow below 700 m.
Terrain and Travel
- Back off slopes as the surface becomes moist or wet with rising temperatures.
- Minimize overhead exposure; avalanches triggered by warming or cornice fall may be large and destructive.
- Carefully evaluate steep lines for wind slabs.
Problems
Loose Wet
Another day of warm weather will destabilize surface snow. The most warming will occur on sun-exposed slopes during the heat of the day. However, the freezing level will be above the mountain tops, meaning that steep slopes on all aspects should be treated as suspect, particularly if you notice moist snow on the surface.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Cornices
Cornices are large at this time of year and they will undergo rapid weakening during this warming trend. Avoid travelling close to them while on ridges and limit your exposure on slopes beneath them.
Aspects: All aspects.
Elevations: Alpine.
Likelihood
Expected Size
Wind Slabs
Triggering wind slab avalanches remains possible after strong northeast wind formed slabs in atypical terrain features last week. Use extra caution as you approach steep slopes in exposed terrain, particularly near ridge lines.
Aspects: All aspects.
Elevations: Alpine.
Likelihood
Expected Size
Valid until: Mar 17th, 2020 4:00PM
