Avalanche Forecast
Issued: Mar 12th, 2021 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Cornices, Persistent Slabs and Loose Wet.
ldreier,
Avalanche Canada
It's going to be a hot and sunny day! Solar input and the freezing level rising to 2700 m will weaken cornices and may increase the reactivity of the persistent weak layers. Be alert to conditions that change with sun exposure and daytime heating.
Summary
Confidence
Weather Forecast
FRIDAY NIGHT: Clear, 15 km/h southwest wind, alpine low -9 C, freezing level at valley bottom.
SATURDAY: Sunny, 10 km/h southwest wind, alpine high +7 C, freezing level 2700 m.
SUNDAY: Sunny, 15 km/h south wind, alpine high +8 C, freezing level 2500 m.
MONDAY: Mix of sun and cloud, trace of new snow, 15 km/h northeast wind, freezing level 2200 m.
Avalanche Summary
A few small avalanches were reported on east aspects on Friday. A few small loose and slab avalanches were triggered on sun-exposed slopes in the alpine during the heat of the day on Wednesday.
Snowpack Summary
A few centimetres of snow overlies a thick melt-freeze crust in many areas, with the exception being on north aspects above around 1700 m. Wind slabs may still exist on northerly aspects at alpine and treeline elevations. On solar aspects and below the freezing level, the snow may moisten during the heat of the day. Cornices may also weaken over the day.
Around 30 to 50 cm of snow overlies a variety of old interfaces that formed in mid-February. There hasn't been recent avalanche activity on this layer, but it remains possible to be triggered where it exists. The more active layer was buried late January, which is found 50 to 100 cm deep. This layer is mostly composed of sugary faceted grains, hard wind pressed snow, feathery surface hoar in wind-sheltered locations, and a melt-freeze crust on steep solar aspects. Periodic avalanches continue to be triggered on this layer. Check out this MIN for a photo of the positioning of these layers in the snowpack.
Terrain and Travel
- Cornices become weak with daytime heating or solar exposure.
- Cornices often break further back than expected; give them a wide berth when traveling on ridgetops.
- Be aware of the potential for large avalanches due to the presence of a persistent slab.
- Avoid exposure to steep, sun exposed slopes, especially when the solar radiation is strong.
- Be alert to conditions that change throughout the day.
Problems
Cornices
Cornices will become weak with daytime heating and the freezing level rising to 2700 m. Large cornice falls are a hazard of their own and can also trigger large persistent slab avalanches on the slopes below.
Aspects: North, North East, East, South East, West, North West.
Elevations: Alpine.
Likelihood
Expected Size
Persistent Slabs
Two weak layers may exist between 30 and 100 cm deep. Widespread avalanche activity has already occurred on the layers, but they could still be triggered anywhere they haven't already failed. Look for signs of instability and continue treating the snowpack as suspect if you are uncertain whether the layer is still present in your riding area. The warm temperatures may increase the reactivity of these layers.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Loose Wet
Solar input and warm temperatures may weaken the upper snowpack and form wet loose avalanches. These avalanches will most likely occur on steep solar slopes and around rock outcrops. The likelihood for wet loose avalanches will increase with daytime heating. Pinwheeling and a moist snow surface are signs that the stability of the upper snowpack is decreasing.
Even small avalanches can be a hazard in high consequence terrain and above terrain traps.
Aspects: South East, South, South West.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Mar 13th, 2021 4:00PM
