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 4th, 2013–Mar 5th, 2013

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

Regions

South Columbia.

Confidence

Fair - Due to variable snowpack conditions for the entire period

Weather Forecast

Synopsis: A ridge of High pressure over the Eastern Pacific will provide a mix of sun and clouds with some chance of light precipitation for the next 2-3 days. Winds are expected to be light Northeasterly and alpine temperatures should be around -11.0.

Avalanche Summary

Reports of a widespread natural avalanche cycle up to size 3.0 during the recent storm. Some avalanches were reported to have released in the storm snow down about 40 cms and resulted in avalanches up to size 2.0. It may take a couple of days to decide if the recent storm cleaned out most of the weak February 12th surface hoar, or if the weak layer will continue to be triggered by human activity.

Snowpack Summary

The storm snow is expected to settle and bond to the old surface over the next few days. A crust has formed up to about 1800 metres where the recent warm storm had turned to rain. In the alpine there may be a weak layer in the storm snow that was developed during a temperature change in the middle of the storm. Below the storm snow lies a highly reactive weak layer of surface hoar (and/or a crust) which was buried on February 12th. Deeper persistent weak layers from early February and late January continue to show planar failures when moderate to hard forces are applied in snow pack tests. In particular, in the Monashees, a rain crust buried down 150 cm has been responsible for a couple of recent large, surprising avalanches.

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.

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.

Cornices

Cornice Fall is the release of an overhanging mass of snow that forms as the wind moves snow over a sharp terrain feature, such as a ridge, and deposits snow on the downwind (leeward) side. Cornices range in size from small wind drifts of soft snow to large overhangs of hard snow that are 30 feet (10 meters) or taller. They can break off the terrain suddenly and pull back onto the ridge top and catch people by surprise even on the flat ground above the slope. Even small cornices can have enough mass to be destructive and deadly. Cornice Fall can entrain loose surface snow or trigger slab avalanches.