North Columbia

Generally safe avalanche conditions this weekend may deteriorate into next week. Re-evaluate avalanche danger and ease into terrain cautiously after any big changes in the weather. This is the last forecast for the season. Thanks for the great winter and play safe!

Friday night: Clear, light wind, alpine temperature near -5, freezing level valley bottom.

Saturday: Mostly cloudy with isolated flurries up to 5 cm, light wind, alpine high near -5, freezing level 1600 m.

Sunday: Mostly cloudy with isolated flurries, light wind, alpine high near -5, freezing level 1600 m.

Monday: Mix of sun and cloud, moderate southwest wind, alpine high near -2, freezing level 2100 m.

Warm temperatures last week resulted in widespread wet avalanche activity. The most notable activity was on Saturday where there was both widespread size 1-2 wet loose avalanches and a few larger and destructive (size 2.5-3.5) wet slab avalanches. The large wet slabs were mostly on south and west facing slopes. Avalanche activity has been on the decline since then with relatively cooler temperatures. A cornice fall triggered a large (size 3) slab avalanche on a north-facing alpine ridge in Glacier National Park on Tuesday.

The cooling trend will make wet avalanches problems unlikely in the coming days, making cornices the primary concern. 

The upper snowpack has undergone multiple melt-freeze cycles and is now crusty and refrozen in the cooler temperatures. Dry snow may still be found on northerly aspects above roughly 2300 m. There are no layers of concern in the snowpack, which has been melting and settling over the past week. Large cornices loom along many ridgelines.

• Minimize exposure to sun-exposed slopes when the solar radiation is strong.
• When a thick, melt-freeze surface crust is present, avalanche activity is unlikely.
• Pay attention to cornices and give them a wide berth when traveling on or below ridges.
• Carefully evaluate steep lines for wind slabs.