South Columbia

South Columbia

Date Issued:

Valid Until:

Forecaster: mbender

A persistent slab problem still exists. Although the likelihood of triggering of the persistent slab problem has reduced, the consequences of doing so would be high.

Sun, 24 FebMon, 25 FebTue, 26 Feb
Alpine2 Moderate2 Moderate1 Low
Treeline2 Moderate2 Moderate2 Moderate
Below Treeline2 Moderate2 Moderate2 Moderate
Confidence: High - The weather pattern is stable
Sun, 24 FebMon, 25 FebTue, 26 Feb
Alpine2 Moderate2 Moderate1 Low
Treeline2 Moderate2 Moderate2 Moderate
Below Treeline2 Moderate2 Moderate2 Moderate
Confidence: High - The weather pattern is stable

Persistent Slabs

Travel and Terrain Advice

  • Be aware of the potential for wide propagation.
  • Avoid steep, open and/or sparsely treed slopes at and below treeline.
  • Watch for whumpfing, hollow sounds, and shooting cracks.

Wind Slabs

Travel and Terrain Advice

  • Use caution in freshly wind-loaded features, especially near ridge crests and in steep terrain.
  • If triggered the wind slabs may step down to deeper layers resulting in large avalanches.
  • Wind from a variety of directions has formed wind slabs in unusual locations.

Forecast Details

Avalanche Summary

Friday's avalanche activity was reported as several skier triggered wind slabs to size 1.5 on northerly aspects at treeline and in the alpine along with numerous loose snow and thin storm slab avalanches to size 1 and 1.5.

On Thursday, there were three reports of human triggered persistent slab avalanches up to size 2. These were on north and northeast aspects at treeline and below treeline, and they failed on a persistent weak layer that was buried in mid January. There were also reports of several size 1 human triggered wind slab avalanches in the alpine and at treeline.

On Wednesday, there were numerous reports of human triggered avalanches up to size 2, primarily on east and southeast aspects at all elevations. Four of these were persistent slab avalanches that were triggered remotely (from a distance) by people. They were on east aspects below treeline and failed on a persistent weak layer that was buried mid January. Persistent slab avalanche activity on the mid January weak layer has slowed down to some degree but it has not stopped, and avalanches continue to be triggered by humans on a regular basis. These avalanches tend to be large, potentially high consequence events.

Snowpack Summary

5-15 cm of new snow falling Thursday and Friday has been redistributed by moderate southwest winds. This new snow is sitting on older wind slabs which may exist on all aspects. This brings total recent snowfall amounts to 20-60 cm which overlies a weak layer of surface hoar (feathery crystals) and crust that was buried in early February.

Two additional weak layers of surface hoar have produced large avalanches in the region over the past month. A layer buried at the end of January is around 40 cm deep and a layer buried mid-January is between 50 and 90 cm deep. The mid-January layer may also be associated with a crust on southerly aspects. These layers are most prominent at treeline and below.

The remainder of the snowpack is generally considered to be strong. However, there have been sporadic reports of very large avalanches that have released near the base of the snowpack. Most of these avalanches have been in the high alpine.

Weather Forecast

SUNDAY: Sunny with cloudy periods / light northeast wind / alpine temperature -11

MONDAY: A mix of sun and cloud / light east wind / alpine temperature -13

TUESDAY: Mostly sunny / light to moderate east wind / alpine temperature -15

Source: avalanche.ca

South Columbia