The South Columbia region may receive up to 25 cm of snow by Thursday afternoon. Human triggered avalanches are possible, especially in wind loaded areas, and at lower elevations where buries surface hoar exists.
Summary
Confidence
Moderate - Forecast snowfall amounts are uncertain on Thursday
Weather Forecast
Convective snow showers on Thursday could mean that some areas receive higher than forecast snowfall amounts.WEDNESDAY NIGHT - Mainly cloudy with flurries, up to 5 cm / southeast winds 10-20 km/h / alpine low temperature near -10THURSDAY - Mainly cloudy with flurries, 5-10 cm. / southwest winds 10-20 km/h / alpine high temperature near -8FRIDAY - Mainly cloudy with flurries, 3-5 cm / southwest winds 10-30 km/h / alpine high temperature near -10SATURDAY - A mix of sun and cloud / northwest winds, 10-20 km/h / alpine high temperature near -10
Avalanche Summary
Observations from the past few days have shown size 1-2 wind slabs releasing with skier traffic on a range of aspects in the alpine and at treeline. Small (size 1-1.5) loose dry avalanches have also been observed releasing naturally from steeper, sun exposed slopes. Persistent slab avalanche activity on the mid-January weak layer has slowed down, but not stopped. This layer has evolved a lower likelihood avalanche problem focused at treeline and below. Check out the great photos from a
MIN report dated from February 23 for a higher consequence example of this layer's potential. Take note of the low angle terrain, treeline elevation, and the light load of a single ski track that triggered this avalanche.
Snowpack Summary
5-15 cm of snow is expected to fall over Wednesday night and Thursday with mainly light southerly winds. Some convective snow showers on Thursday could mean that some areas receive up to 25 cm.The new snow will likely sit on wind slabs, surface hoar (feathery crystals) and facets (sugary snow), and a crust on sun exposed slopes. The wind slabs may continue to be reactive since they are sitting on facets.There are three prominent weak layers in the upper snowpack that were buried in mid and late January, and early February. They can be found between 30-90 cm below the surface. These layers consist primarily of surface hoar, though they may be associated with crusts on steeper, south facing slopes. These weak layers have been most prominent and most reactive at lower elevations - especially below treeline.The lower snowpack is generally considered to be strong, except for shallow, rocky areas where the cold temperatures continue to facet (weaken) the snowpack.
kdevine,
Avalanche Canada
