Avalanche Forecast
Issued: Mar 14th, 2020 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs, Loose Wet and Deep Persistent Slabs.
mconlan,
Avalanche Canada
Expect to find wind slabs in atypical terrain due to northeast wind. The day will progressively warm up and the sun could moisten snow on sun-exposed slopes and weaken cornices.
Summary
Confidence
Weather Forecast
SATURDAY NIGHT: Clear skies, moderate northeast wind, alpine temperature -18 C.
SUNDAY: Clear skies, moderate to strong northeast wind, alpine temperature -9 C, freezing level rising to 1000 m.
MONDAY: Clear skies, light to moderate north wind, alpine temperature 0 C, freezing level 2100 m.
TUESDAY: Clear skies, light to moderate northeast wind, alpine temperature -1 C, freezing level 1800 m.
Avalanche Summary
No new avalanches were observed on Friday and there were no reports available for Saturday. A naturally-triggered wind slab avalanche was observed on Thursday, as seen in this MIN.
It will remain possible for humans to trigger wind slab avalanches. Loose wet avalanche activity and cornice falls could also be triggered with the warming trend.
Snowpack Summary
A major warming trend is forecast for the coming days, which could rapidly weaken the snowpack and cornices. Wind slabs may be found on all aspects due to variable wind directions. Recent wind has blown from the northeast, forming fresh wind slabs in south to southwest terrain features at higher elevations. In sheltered terrain, about 30 cm of snow may overly a melt-freeze crust and potentially small surface hoar crystals in isolated features.
In the northern part of the region (i.e., Duffey/Hurley/Gold Bridge), a deep instability may linger at the base of the snowpack. It has not produced an avalanche since February 17th. Human-triggering is unlikely, though if one were to trigger the layer, it would likely be in a thin, shallow, rocky spot. A large load, such as from a cornice fall, or sustained warm air temperature have the potential to trigger this layer.
Terrain and Travel
- Carefully evaluate steep lines for wind slabs.
- Be aware of highly variable recent wind loading patterns.
- Extra caution for areas experiencing rapidly warming temperatures for the first time.
- The likelihood of deep persistent slab avalanches will increase with each day of warm weather.
- Pay attention to cornices and give them a wide berth when traveling on or below ridges.
Problems
Wind Slabs
Wind from variable directions has likely formed wind slabs on all aspects. The most recent wind has been from the northeast, meaning you may find wind slabs in atypical terrain features. Fresh slabs could form quickly on Saturday with new snowfall in the south of the region. Use caution as you enter wind-affected terrain.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Loose Wet
The snowpack will undergo a rapid change as the freezing level rises and clear skies prevail. For Sunday, loose wet avalanche activity is most likely during the heat of the day on sun-exposed slopes. Cornices will also weaken with the warming trend.
Aspects: South East, South, South West.
Elevations: All elevations.
Likelihood
Expected Size
Deep Persistent Slabs
In the north of the region (e.g. Duffey, Hurley, Goldbridge), a deep persistent weak layer of faceted grains near the ground presents a lingering concern on steep, shallow slopes in the alpine. The likelihood of triggering this layer may increase over the coming days with an increasing freezing level.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Mar 15th, 2020 5:00PM
