Forecasts are based on limited observations. Dig down, test weak layers and keep an eye on rising temperatures.
Confidence
Fair - Due to the number of field observations
Weather Forecast
High pressure will strengthen though the forecast period bringing strong inversions (warmer temperatures) at upper elevations. No precipitation expected.Sunday/ Monday: A mix of sun and cloud. Alpine temperatures 0 degrees. Freezing levels near 2500 m. Ridgetop winds from the NW. Tuesday: Mainly sunny. Alpine temperatures below 0 degrees. Freezing levels falling to 1300 m. Ridgetop winds will be light from the NW.
Avalanche Summary
No recent avalanches reported. Earlier in the week a widespread cycle up to size 3 occurred throughout the region. Many of these avalanches ran on the October crust/ facet combo near the base of the snowpack.
Snowpack Summary
The average snowpack depths at upper elevations are near a metre or more. Wind slab problems likely exist on lee slopes.A bigger concern deeper in the snowpack is a melt-freeze / rain crust that formed early October. This is generally found from 70-120 cm down, with facetted (sugary) crystals above and below that are bonded poorly. The crust/ facet combo may be more predominant on Northerly aspects and allow for wider propagations, especially in places that have smooth ground cover (glacier ice, grassy slopes, rock slabs etc.).Snowpack conditions may change and deteriorate as temperatures rise in the alpine.
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.