Archived

Avalanche Forecast

Nov 27th, 2018–Nov 28th, 2018

Alpine

3: Considerable

The avalanche danger rating in the alpine will be considerable

Treeline

3: Considerable

The avalanche danger rating at treeline will be considerable

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

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

2: Moderate

The avalanche danger rating below treeline will be moderate

Regions: Kootenay Boundary.

The storm should offer one last pulse of snow and wind Tuesday night before it exits to the east. Both surface hoar and crust are just under the new snow, so conservative terrain selection remains prudent as the snowpack adjusts to this new load.

Confidence

Low - Due to the number of field observations

Weather Forecast

The system that has brought significant rain in the valley bottoms and upwards of 30 cm of snow to the Boundary region should offer one last pulse Tuesday night. Wednesday marks the start of what looks to be a pretty significant drying trend as cold air begins to descend from the Arctic. No significant precipitation is expected for the forecast period and it looks like there is potential for clear skies by Sunday.TUESDAY NIGHT: Freezing level around 1000 m, moderate to strong west/southwest wind, 1 to 5 cm of snow possible with light rain in the valley bottoms.WEDNESDAY: Overcast, freezing level holding around 1400 m, light to moderate southwest wind, trace of precipitation possible.THURSDAY: Scattered cloud cover, freezing level around 1000 m, light variable wind, no significant precipitation expected.FRIDAY: Scattered cloud cover, freezing level beginning near valley bottom rising to 1000 m, light variable wind, no significant precipitation expected.

Avalanche Summary

A MIN report from Saturday describes a snowboarder triggering and getting caught in a smaller (size 1) storm slab that appeared to have been formed by cross-loading winds in the Ymir bowl area. See the full report on the MIN here.On Saturday in the Meadow Creek area of the neighbouring South Columbias, a group of snowmobilers triggered a large deep persistent slab that released to ground and resulted in multiple involvements. Although still an isolated event, travelers should be aware of roughly similar snowpack characteristics in the Kootenay Boundary region and maintain cautious travel practices - especially in complex terrain at higher elevations. See the full report on the MIN here.Please submit any observations you have to the Mountain Information Network here.

Snowpack Summary

Alpine snow depths in the region are around 70 to 90 cm. 10 to 40cm of recent snow overlies a layer of surface hoar that was buried on November 21. This layer is expected to be variable in nature and may be sitting on a crust in some locations. On solar aspects it may have been melted into a crust.

Avalanche Problems

Storm Slabs

Widespread storm slabs averaging 30 cm in depth are sitting on a weak layer of surface hoar (feathery crystals) and sun crust on steep south facing slopes. Expect to find deeper deposits on this layer in wind loaded areas.

Use caution on sheltered shady steep slopes where buried surface hoar may be preserved.Be careful with wind loaded and cross-loaded pockets around ridge crests and gullies.Watch for signs of instability such as whumpfing, or cracking.

Aspects: All aspects.

Elevations: All elevations.

Likelihood: Possible - Likely

Expected Size: 1 - 2