North Columbia Avalanche Forecast

Feb 18th, 2020 5:00PM

The alpine rating is moderate, the treeline rating is moderate, and the below treeline rating is low. Known problems include Storm Slabs.

Enjoy the sunny weather, but remain cautious around sun-exposed and wind affected slopes.

Summary

Confidence

High - The number, quality, or consistency of field observations is good, and supports our confidence.

Weather Forecast

TUESDAY NIGHT: Clear, light northwest wind, alpine temperatures drop to -15 C.

WEDNESDAY: Sunny, light southwest wind, alpine high temperatures around -5 C.

THURSDAY: Sunny, moderate southwest wind, alpine high temperatures around -5 C.

FRIDAY: Sunny in the morning with increasing cloud in the afternoon, moderate southwest wind, alpine high temperatures around -5 C.

Avalanche Summary

Several human triggered slabs were reported on north and east facing slopes on Monday. Most of these were small (size 1) with 10-30 cm thick crowns. One larger (size 2) slab avalanche was triggered by a falling cornice on a north-facing slope at 2000 m and released on a 35 cm deep surface hoar layer. On Sunday there were reports of a few small slabs triggered above the rain crust at low elevations in steep gully features, a small slab running on a sun crust on southeast slope at treeline, and another small slab failing on a surface hoar layer on a west aspect in the trees. Although these avalanches were small, they highlight the potential to trigger storm slabs on a wide variety of terrain.

Snowpack Summary

Sunny weather could weaken cornices and snow on steep south-facing slopes. 30-60 cm of recent storm snow is gradually settling and gaining strength, but has shown some isolated signs of reactivity on wind loaded slopes, steep convexities in sheltered terrain (where the snow sits above small surface hoar or sun crusts), and steep gully features at low elevations (where the snow may be poorly bonded to the early February rain crust). These interfaces are unlikely to develop into a persistent problem, but for the next few days storm slabs could remain reactive on these isolated terrain features. The lower snowpack is generally well settled and strong.

Terrain and Travel

  • Minimize exposure to sun-exposed slopes when the solar radiation is strong.
  • Be careful as you transition into wind affected terrain.
  • Watch for signs of instability like whumpfing, hollow sounds, shooting cracks or recent avalanches.

Problems

Storm Slabs

An icon showing Storm Slabs

Likelihood

Unlikely-Possible

Expected Size

1 - 2

Storm slab avalanches are possible to trigger on wind loaded or steep convex slopes, and may release naturally on sun-exposed slopes in the heat of the day.

Aspects:

All aspects.

Elevations:

All elevations.

Valid until: Feb 19th, 2020 5:00PM