Dashboard Regions Weather Stations Radar Alerts Glossary
Contact About
Log In

Register for an account and never miss a forecast again!

Register

Avalanche Forecast

Archived

Apr 6th, 2023–Apr 7th, 2023

Alpine
Natural avalanches unlikely, human triggered possible.
Treeline
Natural avalanches unlikely, human triggered possible.
Below Treeline
Below Threshold.
Alpine
Natural avalanches unlikely, human triggered possible.
Treeline
Natural avalanches unlikely, human triggered possible.
Below Treeline
Below Threshold.
Alpine
Natural avalanches possible, human triggered probable.
Treeline
Natural avalanches unlikely, human triggered possible.
Below Treeline
Below Threshold.

Regions

Yukon, Tutshi, Wheaton, White Pass East, White Pass West.

Wind slabs remain the primary concern. Watch for wind slabs around ridgelines and in mid slope terrain features in areas that see stronger winds.

Reactivity may increase on south facing slopes, even with brief periods of sunshine.

Confidence

Moderate

Avalanche Summary

Reactive wind slabs were reported on Sunday at alpine elevations in north facing terrain.

On Saturday a rider triggered a cornice fall from a distance, which produced a size 3 persistent slab avalanche on a northeast aspect at 1750 m. The avalanche was 200 cm deep and was suspected to have failed on a layer of facets above a crust buried in January.

Snowpack Summary

Up to 25 cm of recent snowfall will continue to be redistributed by southerly winds into wind slabs over previously wind affected snow on north and east facing slopes. South facing terrain will likely be stripped back to a crust by these winds. Lower elevations likely have a crust on the surface from recent warm temperatures.

A weak layer of surface hoar/crust/facets buried in early January is now over 1 m deep in most areas. This layer has produced recent avalanche activity and remains a concern in terrain where the snowpack is thin. The lower snowpack consists of basal facets, particularly in shallow areas.

Weather Summary

Thursday Night

Cloudy with 5-10 cm of new snow. Moderate to strong southerly winds. Freezing levels drop to valley bottom.

Friday

Mostly cloudy with up to 5 cm of snowfall. Moderate southerly winds. Freezing levels remain below 1000 m.

Saturday

5 cm of snow with strong to extreme southerly winds. Freezing levels around 1000 m.

Sunday

Light snowfall with strong southerly winds. Freezing levels around 1000 m.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

  • Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
  • Carefully evaluate steep lines for wind slabs.
  • Use caution on large alpine slopes, especially around thin areas that may propagate to deeper instabilities.
  • Pay attention to cornices and give them a wide berth when traveling on or below ridges.

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.

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.

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.