Avalanche Forecast
Issued: Jan 19th, 2020 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Storm Slabs and Persistent Slabs.
mconlan,
Avalanche Canada
A warming trend means that slabs may become sensitive to human traffic. The warming also has the possibility of waking up a buried weak layer in the eastern and northern parts of the region.
Summary
Confidence
Weather Forecast
SUNDAY NIGHT: Cloudy with isolated flurries, accumulation trace to 2 cm, moderate to strong southwest wind, alpine temperature -4 C, freezing level rising to 700 m.
MONDAY: Cloudy with light snowfall, accumulation 2 to 5 cm, moderate to strong southwest wind, alpine temperature -5 C, freezing level 1200 m.
TUESDAY: Cloudy with snowfall, accumulation 5 cm, light to moderate south wind, alpine temperature -6 C, freezing level below valley bottom.
WEDNESDAY: Morning snowfall then a mix of sun and cloud, accumulation 2 to 5 cm, light southwest wind, alpine temperature -8 C, freezing level below valley bottom.
Avalanche Summary
A few small (size 1) storm slab avalanches were triggered naturally and by humans on Saturday. They were generally 10 to 20 cm thick and on all aspects
Although over a week old now, there were a few notable reports of large persistent slab avalanches in the Selkirks and the northern tip of the Monashees (near Blue River and Valemount) last weekend. The avalanches failed on a 100 cm deep surface hoar layer on north and east aspects between elevations of 1200 to 2100 m. Observations suggest this layer has trended towards being less reactive. There is uncertainty on whether the layer will wake up on Monday with a rise in air temperature.
Snowpack Summary
Around 10 to 30 cm of snow has fallen in the past couple of days, with associated strong southwest wind. A rise in the air temperature on Sunday night into Monday will mean that the snow will form slab properties quickly. Expect the most reactive slabs to be in lee terrain features near ridges.
A layer of surface hoar buried 80 to 150 cm deep could still be a concern in certain parts of the Selkriks and the northern end of the Monashees. Although an avalanche has not been reported on this layer since January 13, the likelihood of triggering it may increase as the air temperature warms.
Terrain and Travel
- Avoid freshly wind loaded features, especially near ridge crests, roll-overs and in steep terrain.
- Extra caution for areas experiencing rapidly warming temperatures for the first time.
- Approach steep open slopes at and below treeline cautiously, buried surface hoar may exist.
Problems
Storm Slabs
Around 10 to 30 cm of snowfall accumulated over the weekend and has been accompanied by strong southwest wind. An air temperature rise on Monday will mean that storm slabs may form quickly and become reactive to human traffic. The deepest and touchiest slabs will likely be in lee terrain features near ridges.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Persistent Slabs
A layer of surface hoar is buried 80 to 150 cm deep in the Selkirks and northern tip of the Monashees. As the air temperature rises on Monday, the likelihood of triggering this layer may increase. Use added caution in clearings around treeline during periods of warming.
Aspects: All aspects.
Elevations: Treeline, Below Treeline.
Likelihood
Expected Size
Valid until: Jan 20th, 2020 5:00PM
