Archived

Avalanche Forecast

Feb 19th, 2018–Feb 20th, 2018

Alpine

3: Considerable

The avalanche danger rating in the alpine will be considerable

Treeline

2: Moderate

The avalanche danger rating at treeline will be moderate

Below Treeline

2: Moderate

The avalanche danger rating below treeline will be moderate

Alpine

3: Considerable

The avalanche danger rating in the alpine will be considerable

Treeline

2: Moderate

The avalanche danger rating at treeline will be moderate

Below Treeline

1: Low

The avalanche danger rating below treeline will be low

Alpine

2: Moderate

The avalanche danger rating in the alpine will be moderate

Treeline

2: Moderate

The avalanche danger rating at treeline will be moderate

Below Treeline

1: Low

The avalanche danger rating below treeline will be low

Regions: Kootenay Boundary.

The snow is heavily wind-affected. Stick to sheltered trees to find the best and safest riding.

Confidence

Moderate - Wind speed and direction is uncertain

Weather Forecast

TUESDAY: Mix of sun and cloud, light north wind, alpine high temperatures around -17 C.WEDNESDAY: Mostly sunny, light northwest wind, alpine high temperatures around -15 C. THURSDAY: Mostly sunny, light wind, alpine high temperatures around -12 C.

Avalanche Summary

Widespread storm slab activity was reported on all aspects and elevations on Sunday, including natural avalanches up to size 2 and smaller skier-triggered avalanches (size 1). Similar activity was also reported the previous two days. Looking ahead, natural storm slab activity will wind down but human-triggering remains likely.No avalanches have been reported on persistent weak layers for over a week.

Snowpack Summary

Gusty wind from various directions (primarily northeast) has scoured some exposed slopes and formed fresh wind slabs on others. Sheltered terrain has 30-50 cm of low density snow from recent storms. A crust layer can be found beneath the storm snow on sun-exposed slopes and below 1800 m, but these interfaces have not been involved in recent avalanches.Weak layers that formed in January and December are gradually gaining strength. The layers include several surface hoar and facet layers buried 1-2 m below the surface. No avalanches have been reported on these layers for the past week and snowpack tests are showing improved bonding. Despite these signs, avalanche professionals are still treating these layers with respect and being cautious around shallow start zones and big avalanche paths.

Avalanche Problems

Wind Slabs

Strong wind from various directions has redistributed 30-50 cm of recent snow into touchy slabs at all elevations.

Use conservative route selection, choose moderate angled and supported terrain with low consequence.Use ridges or ribs to avoid pockets of wind loaded snow.Watch for whumpfing, hollow sounds, shooting cracks or recent avalanches.

Aspects: All aspects.

Elevations: All elevations.

Likelihood: Possible - Likely

Expected Size: 1 - 2.5

Persistent Slabs

Several deeply buried weak layers exist in the snowpack. Although the likelihood of triggering a persistent slab is gradually decreasing, the consequences remain high.

Minimize exposure to overhead avalanche terrain, large avalanches may reach run out zones.Caution around convexities or areas with a thin or variable snowpack.If triggered the storm slabs may step down to deeper layers resulting in large avalanches.

Aspects: All aspects.

Elevations: All elevations.

Likelihood: Unlikely

Expected Size: 2.5 - 4