Avalanche Forecast

Archived

Apr 19th, 2019–Apr 20th, 2019

Alpine

Below Threshold.

Treeline

Below Threshold.

Below Treeline

Below Threshold.

Alpine

Below Threshold.

Treeline

Below Threshold.

Below Treeline

Below Threshold.

Alpine

Below Threshold.

Treeline

Below Threshold.

Below Treeline

Below Threshold.

Regions

Little Yoho.

A significant avalanche cycle is underway. Conservative terrain selection Saturday is essential. Avoiding avalanche terrain would be wise.

Weather Forecast

An additional 5 to 10 cm is expected overnight with rain at lower elevations until early hours Saturday as freezing levels drop to valley bottom. Clearing is expected west of the divide with some clouds and flurries potentially lingering to the East. Freezing levels reach around 2000m Saturday afternoon as moderate alpine winds back to light.

Snowpack Summary

Between 60-100 cm of snow has fallen in the last week with snowpack values reaching seasonal highs 2000m and above. Extreme west winds Wed and Fri created widespread windslabs in alpine areas and continued sluffing in steep terrain. Wet snow and weak crusts below 2000m with warm temps and 10-15mm of rain Friday.

Avalanche Summary

Poor visibility with rain below 2000m today. A Cycle of loose dry and loose wet avalanches out of steep terrain is evident below the low ceiling. One slab at approx 1900m on a N aspect stepped down twice to about 80 and 100cm evidence for the idea that N and E aspects were not affected by the significant warming cycle in March.

Confidence

Problems

Wind Slabs

Wind Slab avalanches are the release of a cohesive layer of snow (a slab) formed by the wind. Wind typically transports snow from the upwind sides of terrain features and deposits snow on the downwind side. Wind slabs are often smooth and rounded and sometimes sound hollow, and can range from soft to hard. Wind slabs that form over a persistent weak layer (surface hoar, depth hoar, or near-surface facets) may be termed Persistent Slabs or may develop into Persistent Slabs.

Loose Dry

Loose Dry avalanches are the release of dry unconsolidated snow and typically occur within layers of soft snow near the surface of the snowpack. These avalanches start at a point and entrain snow as they move downhill, forming a fan-shaped avalanche. Other names for loose-dry avalanches include point-release avalanches or sluffs.

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.