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North Rockies Avalanche Forecast - April 15, 2021

Avalanche danger will increase throughout the day due to warm sunny weather. Plan on finishing early and minimizing your exposure to overhead avalanche terrain.
North Rockies Avalanche

Avalanche danger will increase throughout the day due to warm sunny weather. Plan on finishing early and minimizing your exposure to overhead avalanche terrain. 

Thursday

Alpine - Considerable
Treeline - Considerable
Below treeline - Considerable

Friday

Alpine - Considerable
Treeline - Considerable 
Below treeline - Considerable

Saturday

Alpine - Considerable
Treeline - Considerable
Below treeline - Considerable

Avalanche Summary

Natural avalanche activity has been reported on sun-exposed slopes over the last few days, including an impressive photo in this MIN report from Kakwa on Tuesday. Most activity has been relatively small (size 1-1.5) wet loose avalanches, but they will likely get bigger when it gets warmer on Thursday and Friday. A few wind slab avalanches (up to size 2.5) were reported over the weekend, but this problem has likely settled down since then. There have been some large deep persistent slab avalanches triggered by warming to the south around Jasper and Banff, but we are uncertain whether this problem will extend into the North Rockies.

Looking forward, warm sunny weather will drive avalanche danger with wet loose avalanches likely and the possibility for deep persistent slab avalanches in some areas. These problems are best managed by minimizing your exposure to avalanche terrain when it gets warm.

Snowpack Summary

Warm temperatures are melting the surface on all but the highest north-facing slopes, creating weak surface snow during the heat of the day. Crusts may form overnight. Large cornices hang above many ridgelines and will also weaken with the warming.

As heat penetrates deeper into the snowpack it has the potential to reactivate deeper weak layers, including a layer from mid-February and basal layers. The most likely areas to be concerned about deeper weak layers are shallow parts of the region along the eastern slopes of the Rockies like Core Lodge, Wolverine, Bullmoose, Upper Burnt and perhaps around Mt. Robson.

Weather Forecast

THURSDAY: Clear skies, light southeast wind, freezing level reaching 3000 m and treeline temperatures reach +7 C.

FRIDAY: Clear skies, light wind, alpine temperature 5 C, freezing level steady at 3000 m and treeline temperatures around+7 C.

SATURDAY: Clear skies with some high clouds in the afternoon, light west wind, freezing level around 2500 m and treeline temperatures around +5 C.

Travel and Terrain Advice

  • Avoid exposure to sunny slopes, especially in the afternoon.
  • The more the snowpack warms-up and weakens, the more conservative you`ll want to be with your terrain selection.
  • Pay attention to cornices and give them a wide berth when traveling on or below ridges.
  • The likelihood of deep persistent slab avalanches will increase with each day of warm weather.