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

Mar 15th, 2020–Mar 16th, 2020

Alpine
Natural avalanches possible, human triggered probable.
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, 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.

Regions

Kootenay Boundary.

Expect an upward swing in temperatures as the freezing level rises on Monday. This shift in temperature may result in an increased likelihood of triggering persistent slab avalanches. Be especially cautious underneath steep sun exposed slopes and around rock outcrops.

Confidence

Moderate - Uncertainty is due to how the snowpack will react to the forecast weather.

Weather Forecast

SUNDAY NIGHT: Mainly clear, light northeast wind, alpine temperature -8 C.

MONDAY: Clear skies, light northeast wind, alpine temperature -1 C, freezing level 1900 m.

TUESDAY: Mix of sun and cloud, light northeast wind, alpine temperature -2 C, freezing level 1700 m.

WEDNESDAY: Mix of sun and cloud, light northeast wind, alpine temperature -3 C, freezing level 1500 m.

Avalanche Summary

Many wind slab avalanches were triggered on Saturday and Sunday. They were most often on southerly aspects and at treeline and alpine elevations. They were rated as small (size 1.5).

Widespread avalanche activity is starting to quiet down on the surface hoar layer described in the Snowpack Summary. Over the past two weeks, small to large (size 1 to 2) avalanches have released on this surface hoar layer. They have most often released between 1800 and 2300 m on northwest to east aspects.

Snowpack Summary

The upper snowpack is relatively complex. Strong northeast wind has formed wind slabs in south to southwest terrain features near ridges. A few different layers of surface hoar and melt-freeze crust exist, which have recently acted as sliding layers. One such layer buried about a week ago may be found about 20 to 40 cm deep. The most widespread layer was buried late February and is now 60 to 80 cm deep. This layer is most commonly found in open trees (e.g. in this MIN) or sheltered terrain around the upper part of below treeline, treeline, and lower alpine elevations. This layer may only remain a concern in the north and east parts of the region.

The remainder of the snowpack is strong and well-settled.

Terrain and Travel

  • If triggered, wind slabs avalanches may step down to deeper layers resulting in larger avalanches.
  • Be aware of the potential for large avalanches due to the presence of buried surface hoar.
  • Extra caution for areas experiencing rapidly warming temperatures for the first time.
  • 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.