Avalanche Forecast
Issued: Mar 15th, 2021 3:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Loose Wet, Persistent Slabs and Cornices.
jcoulter,
Avalanche Canada
Avalanche hazard will rise with daytime warming and solar input. Time your day to move off slopes before they get moist or slushy. Consecutive days in a row of warm temperatures may increase the reactivity of deeper weak layers and cornices.
Summary
Confidence
Weather Forecast
MONDAY NIGHT: Partly cloudy, trace precipitation possible, wind light south east switching to south west, alpine low -3 C, freezing levels uncertain-especially around Fernie, 1000-1500 m.
TUESDAY: Mostly sunny, light to moderate south west wind, alpine high +4, freezing level 2100 m.
WEDNESDAY: Sunny, light to moderate south west wind, alpine high +6, freezing level 2200 m.
THURSDAY: Increasing cloud, moderate south west wind, alpine high +8, freezing level 2400 m
Avalanche Summary
On the weekend wet loose avalanches size 1-2 were reported from alpine and treeline elevations. A couple of recent cornice falls from the last week have been noted as well. A small (size 1) wind slab was triggered accidentally near Fernie on Saturday. On Thursday-Friday a few solar triggered slabs up to size 2 were noted.
Snowpack Summary
Wind slabs in the alpine may linger, especially on northerly aspects. Snow on all solar aspects and elevation bands has been getting moist by mid morning and may not be getting the best overnight recovery if it is cloudy overnight. Reports suggest snow on north facing terrain above 1500 m has so far remained dry. Cornices are large and looming, and glide cracks are increasing in size...both should be considered unpredictable and given a wide berth.
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 on the radar, especially in alpine terrain as things stay warm. The late January persistent weak layer is found 50 to 100 cm deep. This layer is mostly composed of sugary faceted grains or feathery surface hoar crystals. In specific terrain features the layer is still producing snowpack test results causing some concern for low probability high consequence avalanches, especially in this periods of warming.
Terrain and Travel
- Be alert to conditions that change with aspect and elevation.
- Cornices become weak with daytime heating or solar exposure.
- Avoid sun exposed slopes when the solar radiation is strong, especially if snow is moist or wet
- Be aware of the potential for large avalanches due to the presence of a persistent slab.
Problems
Loose Wet
Sun and warm daytime temperatures can quickly destabilize solar slopes and increase the likelihood of avalanches. Things will deteriorate even faster if we don't get a good overnight re-freeze. 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, and wet loose avalanches may trigger slabs where persistent layers still linger.
Aspects: South East, South, South West, West.
Elevations: All elevations.
Likelihood
Expected Size
Persistent Slabs
Consecutive days of warm temperatures may reactivate persistent weak layers from January and February. 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.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Cornices
Cornices are large and likely weakening with sun and significant daytime heating. Big cornice falls are a hazard on their own but 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
Valid until: Mar 16th, 2021 4:00PM
