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

Feb 23rd, 2020–Feb 24th, 2020

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

Lizard-Flathead.

This forecast is based on 20 or more cm of new snow being on the ground by Monday morning. The new snow is coming to rest on a variety of old surfaces including surface hoar and facets which could allow for surprisingly touchy storm slabs. Time for conservative terrain choices.

Confidence

Low - Uncertainty is due to the timing, track, & intensity of the incoming weather system.

Weather Forecast

There’s quite a bit of uncertainty surrounding Monday’s storm and there is a chance of the “Fernie Effect” kicking in which would enhance snowfall rates. The forecast really mellows out for the rest of the forecast period though.

SUNDAY NIGHT: Freezing level around 1500 m, moderate to strong southwest wind, 8 to 15 cm of snow.

MONDAY: Overcast at dawn with some clearing in the late afternoon, freezing level around 1400 m, light to moderate wind generally out of the southwest, 5 to 10 cm expected with potential for some enhanced convective snowfall throughout the day that could produce as much as 15 cm.

TUESDAY: Broken cloud cover, freezing level starting at valley bottom rising to about 1500 m, light southwest wind at lower elevations, moderate to strong northwest wind at ridge top, no significant snowfall expected.

WEDNESDAY: Scattered cloud cover, freezing level starting at valley bottom rising to about 1500 m, light southwest wind at lower elevations, moderate to strong northwest wind at ridge top, no significant snowfall expected.

Avalanche Summary

No notable avalanche activity has been reported in the region since last Tuesday. Some storm slab avalanche activity is expected Sunday night into Monday.

Snowpack Summary

Sunday's storm snow is covering a variety of old surfaces including a firm crust on solar aspects, soft faceted snow and surface hoar in sheltered areas, and old wind slabs near ridge crest.

A thick rain crust sits 30-60 cm below the surface and can be found up to 2100 m. Avalanche activity was last observed at the faceting interface between this crust and overlying snow on February 17.  

The mid-pack is well settled and strong, but the base of the snowpack contains basal facets that are most prominent in shallow rocky start zones.

Terrain and Travel

  • Don't be too cavalier with decision making, storm slabs may remain sensitive to human triggering.
  • Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
  • Carefully assess open slopes and convex rolls where buried surface hoar may be preserved.

Problems

Storm Slabs

Storm Slab avalanches are the release of a cohesive layer (a slab) of new snow that breaks within new snow or on the old snow surface. Storm-slabs typically last between a few hours and few days (following snowfall). Storm-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.