Avalanche Forecast

Archived

Mar 18th, 2024–Mar 19th, 2024

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches possible, human triggered probable.

Below Treeline

Natural avalanches unlikely, human triggered possible.

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely, human triggered possible.

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely.

Regions

Sea To Sky, Brandywine, Garibaldi, Homathko, Spearhead, Tantalus, Sky Pilot.

Dangerous avalanche conditions persist during the heat of the day when the snow surface is moist.

Minimize exposure to avalanche terrain and overhead hazards until cooler weather arrives.

Confidence

High

Avalanche Summary

On Sunday, natural avalanche activity from prolonged heat continued to be observed, with loose wet, wet slab and persistent slab avalanche activity up to size 3. Steep rocky terrain and direct solar slopes are the most impacted.

We expect natural wet loose and persistent slab avalanche activity to continue until temperatures return to below-freezing.

Snowpack Summary

A melt-freeze crust rapidly deteriorates with daytime heating and solar input to moist or wet snow surfaces at all elevations. The exception is on direct north facing terrain above 2000 m where the surface remains dry.

The top 20 to 50 cm of the snowpack is moist snow. 100 to 250 cm down is a layer of facets overlying a crust. This layer has been the culprit for many recent large avalanches through the extended warm period.

Below the crust, the snowpack is well settled.

Weather Summary

Monday Night

Mainly clear skies. 10 km/h southwest ridgetop wind. Treeline temperature +5 °C with freezing levels remaining above 3000 m.

Tuesday

Mainly sunny. 10 to 25 km/h southwest ridgetop wind. Treeline temperature +2 °C with freezing levels falling to 2500 m in the afternoon.

Wednesday

Mainly cloudy. 10 to 25 km/h southeast ridgetop wind. Treeline temperature +1 °C. Freezing levels rise from 1500 m to 2000 m in the afternoon.

Thursday

Cloudy with 1 to 4 cm of snow. 10 to 25 km/h variable ridgetop wind. Treeline temperature 0 °C. Freezing levels rise from 1000 m to 1500 m in the afternoon.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

Minimize overhead exposure; avalanches triggered by warming or cornice fall may be large and destructive.
Rocks will heat up with daytime warming and may become trigger points for loose wet avalanches
Pay attention to cornices and give them a wide berth when traveling on or below ridges.
Avoid lingering or regrouping in runout zones.

Problems

Loose Wet

Loose Wet avalanches are the release of wet unconsolidated snow or slush. These avalanches typically occur within layers of wet snow near the surface of the snowpack, but they may quickly gouge into lower snowpack layers. Like Loose Dry Avalanches, they start at a point and entrain snow as they move downhill, forming a fan-shaped avalanche. Other names for loose-wet avalanches include point-release avalanches or sluffs. Loose Wet avalanches can trigger slab avalanches that break into deeper snow layers.

Persistent Slabs

Persistent Slab avalanches are the release of a cohesive layer of snow (a slab) in the middle to upper snowpack, when the bond to an underlying persistent weak layer breaks. Persistent layers include: surface hoar, depth hoar, near-surface facets, or faceted snow. Persistent weak layers can continue to produce avalanches for days, weeks or even months, making them especially dangerous and tricky. As additional snow and wind events build a thicker slab on top of the persistent weak layer, this avalanche problem may develop into a Deep Persistent Slab.