Avalanche Forecast

Issued: Mar 24th, 2019 4:24PM

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

jsmith, Avalanche Canada

Northwest Inland.

Avoid steep, rocky terrain in the alpine where there is a shallow or highly variable snowpack depth. This will reduce the likelihood of triggering large persistent slab avalanches.

Summary

Confidence

Moderate - Due to the number of field observations

Weather Forecast

SUNDAY NIGHT: Clearing / Light, northeasterly winds / Alpine low -3 C / Freezing level 1000 m.MONDAY: Sunny / Light, northeasterly winds / Alpine high 0 C / Freezing level 1500 m.TUESDAY: Mix of sun and cloud / Light, southwesterly winds / Alpine high 0 C / Freezing level 1400 m.WEDNESDAY: Mix of sun and cloud / Moderate, easterly winds / Alpine high 0 C / Freezing level 1500 m.

Avalanche Summary

Natural avalanche activity has tapered off, but concern remains for human triggering persistent slab avalanches on a layer of facets that are down 30-50 cm; especially in steep, rocky alpine terrain with a shallow or highly variable snowpack depth.

Snowpack Summary

At upper elevations, 30-50 cm of well settled snow overlies weak facets (sugary snow) that were around March. 10th. which is currently the primary layer of concern for human triggering persistent slab avalanches.Lower down in the snowpack, the base is composed of weak facets. Large avalanches initiating on these facets are most likely in rocky, alpine terrain where there is a shallow or highly variable snowpack depth. They would likely require a large trigger such as a cornice fall, snowmobile, or a group of people standing in the same spot.The prolonged warm spell has transitioned sun exposed slopes in the alpine and all aspects at treeline and below towards becoming isothermal (0 C throughout the snowpack). In these areas that have entered spring conditions, the avalanche hazard will fluctuate greatly depending on the strength of the overnight freeze and how quickly the snowpack is warmed up each day. Check out this guide to managing avalanche hazard during spring conditions HERE.

Problems

Persistent Slabs

Human triggering of large persistent slab avalanches are most likely in rocky, alpine terrain with a shallow or highly variable snowpack depth.

Avoid steep, rocky terrain in the alpine where there is a shallow or highly variable snowpack depthUse extra caution around moraines that tend to have highly variable snowpacks.Avoid re-grouping in rocky areas with a shallow snowpack, remote triggering is still possible.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

1.5 - 3

Loose Wet

This problem is more likely at lower elevations where there was a weak or no overnight re-freeze. Sunshine and air temperatures above 0 C can rapidly increase the likelihood of triggering loose wet avalanches.

Avoid terrain traps such as cliffs and gullies that increase the consequence of small avalanches.Avoid sun exposed slopes when the solar radiation is strong, especially if the snow is moist or wet.Cornices become weak with daytime heating, travel early on exposed slopes.

Aspects: All aspects.

Elevations: Treeline, Below Treeline.

Likelihood

Possible

Expected Size

1 - 2

Valid until: Mar 25th, 2019 2:00PM