Avalanche Forecast

Archived

May 15th, 2017–May 16th, 2017

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.

This is the last scheduled avalanche bulletin for the season. Above average snowpack at high elevations means we should have an extended spring ski season! Check out the Mountain Conditions Report weekly regional summaries for up to date conditions.

Weather Forecast

Some helpful weather links:

Remote weather stations in Banff, Yoho & Kootenay - Real time, raw, actual weather data.

Avalanche Canada Mountain Weather Forecast - Good for getting an overview of the major weather systems.

SpotWx - Good for a localized forecast

Environment Canada Yoho forecast - Simplified valley bottom forecast for Lake Louise area.

Snowpack Summary

Isothermal snow exists at lower elevations. Crusts formed during clear cool nights will break down quickly with solar inputs. Expect moist surface snow to mountain top in the afternoon with the exception of high elevation North slopes. The basal facet weakness persists at treeline and above and is reactive to large triggers or warm temperatures.

Avalanche Summary

In general, avalanche hazard will be greatest during hot sunny days or warm rain. This has the potential to trigger smaller loose wet avalanches and larger wet slab avalanches on the basal weak layer. For current avalanche activity and observations, check out the Mountain Conditions Report

Confidence

Problems

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.

Wet Slabs

Wet Slab avalanches are the release of a cohesive layer of snow (a slab) that is generally moist or wet when the flow of liquid water weakens the bond between the slab and the surface below (snow or ground). They often occur during prolonged warming events and/or rain-on-snow events. Wet Slabs can be very unpredictable and destructive.

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.