Avalanche Forecast

Issued: Mar 19th, 2019 4:48PM

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

swerner, Avalanche Canada

South Coast.

Persistent warm temperatures are penetrating and destabilizing the upper snowpack. Natural avalanche activity is possible especially on sun exposed slopes. Avoid travel under avalanche paths especially with looming cornices overhead.

Summary

Confidence

Moderate -

Weather Forecast

Warm temperatures persist through the forecast period. WEDNESDAY: Sunny with cloudy periods and treeline temperatures near +16 degrees. Ridgetop winds moderate from the southast and freezing levels above 3000 m. THURSDAY: Mix of sun and cloud. Treeline temperatures +10 degrees with freezing levels 2300 m. Ridgetop winds light from the southwest. FRIDAY: Cloudy with isolated rain showers and some flurries at higher alpine elevations. Treeline temperatures near +4 degrees and freezing levels dropping to 2000 m. Ridgetop winds moderate from the South.

Avalanche Summary

On Monday, a widespread natural wet loose avalanche cycle occurred and was reported up to size 1.0. As the heat continues to penetrate the snowpack we suspect natural wet avalanches will continue through the forecast period.

Snowpack Summary

Snow surfaces are variable and the heat has likely eliminated any trace of cold snow except on high elevation north features. Melt-freeze conditions (more melt then freeze at lower elevations) exist on all other aspects and elevations and signs of snowballing, surface sluffing and loose wet avalanches are current.Deeper in the snowpack a layer of weak and sugary faceted grains sits on a melt-freeze crust about 50 to 120 cm deep. This layer is most prominent in the North Shore Mountains on north aspects. With little overnight re-freeze the warm temperatures will penetrate deeper and continue to destabilize the snowpack and possible imitating larger persistent slab avalanches. Itâ€™s hard to say how many hot days and warm nights it will it take to wake up the more deeply buried weak layers that we haven't thought about in a long time.

Problems

Loose Wet

Loose wet activity is expected to continue on all aspects and elevations except north facing, alpine slopes. Cornices are softening up and weak. You don't want to be under or near one of these looming monsters when they fail.

Avoid slopes when the solar radiation is strong, especially if they have large cornices overhead.Cornices become weak with daytime heating or solar exposure.Avoid exposure to terrain traps where the consequences of a small avalanche could be serious.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely - Very Likely

Expected Size

1 - 2

Persistent Slabs

Warm temperatures are penetrating deeper into the snowpack and a cohesive slab now sits above a weak layer. Its hard to say how long it will take for this warming to wake up the more deeply buried weak layers.

Avoid all avalanche terrain.The likelihood of deep persistent slab avalanches will increase with each day of warm weather.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

1.5 - 2.5

Valid until: Mar 20th, 2019 2:00PM