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Weekend conditions update — Feb. 26

 | February 26, 2021

Every weekend SPIN will compile the current avalanche forecasts and weather for the Interior. As a reminder, we’ve pulled this information together for a convenient overview to help make your initial plans and recommend reading the full avalanche forecast, and checking and assessing conditions on your own specific to your unique location. Tune in at the end of each week to get the forecast before your weekend

For those of you headed north from Sun Peaks this weekend, be advised there is a Special Public Avalanche Warning (SPAW) for the Cariboos, North and South Rockies, as well as Waterton Lakes National Park.

The warning will be in place until the end of the weekend and will be reassessed Monday morning by Avalanche Canada forecasters.

A persistent weak layer (PWL) is the main culprit in the above regions and avalanches on the PWL have resulted in two avalanche fatalities in the North Rockies and a near-miss in the South Rockies.

Avalanche Canada warned that the PWL exists throughout the province but is more susceptible to human triggering in the above mentioned avalanche regions.

“The next wave of storms is going to make for great riding but will also increase the load on these persistent weak layers, making avalanches even easier to trigger,” explained Warning Service Manager Karl Klassen. “This string of fatal and serious incidents should be a wake up call for all backcountry users. This layer is deep enough that it’s not easily seen, but large and destructive human triggered avalanches are expected.”

Weekend Weather

The Meteorological Service of Canada, via Avalanche Canada’s Mountain Weather Forecast, has predicted that tonight an arctic cold front will bring up to five centimetres of snow to the Interior. 

The cold front will complete its journey across the province Saturday morning followed by a ridge of high pressure with dry and clear skies and winds up to 30 km/h during the day.

A subsequent warm front will deliver rising freezing levels and five more centimetres of snow with moderate westerly winds overnight Saturday.  

A cold front will move its way towards the Interior Sunday night while a low pressure system develops over the south of the province with strong winds changing from south 60-80km/h to north 30-50km/h.

A trailing trough is expected to land on the coast and make its way inland Monday night.

Sun Peaks Resort is forecasting a mix of sun and cloud Saturday with 15km/h northwest winds gusting to 30km/h in the alpine but changing to southwest in the afternoon and a high of -6C.

Sunday’s forecast shows a low of -7C and high of -4C meanwhile snow is out of the local forecast until Monday.

Avalanche forecast

In the Cariboos (where the SPAW is active) as well as the North and South Columbia avalanche regions, the avalanche forecast is considerable at all elevations today while slightly dropping throughout the weekend.

Saturday all regions are forecasted as considerable treeline and above and moderate below treeline while Sunday shows a considerable rating in the alpine and moderate treeline and below.

The three regions also have the same avalanche problems, storm slabs and persistent slabs.

The storm slab problem will be brought on by weekend snow and strong winds treeline and above on all aspects with a likely chance of producing up to size two avalanches. 

Wind loaded areas will be of special concern as storm slabs and cornices are expected to build this weekend. Caution on ridges and lee features is advised.

The second avalanche problem consists of a persistent slab at all elevations and aspects. It is likely to trigger size 2-3.5 avalanches in the North Columbias and Cariboo regions while in the South Columbia region there is a likely chance of size 2-2.5 avalanches.

Various persistent weak layers currently exist in the snowpack.

For the North and South Columbia regions, two weak layers exist. The first is down 40-80cm and consists of sugary facets below storm snow while the second from late January is buried 80-120cm consisting of surface hoar. Isolated and sporadic avalanche activity has been noted to occur on this layer.

It is important to once again note the Cariboos be of special concern considering the SPAW. 

There are three persistent weak layers, the first is found 40-80cm below storm snow on sugary facets, while the other two are composed of surface hoar or facets on a sun crust and are anywhere from 80-200cm down, most commonly found at treeline or in cut-blocks. While the deeper two weak layers have not produced any large avalanches in the Cariboos, they have been the cause of recent large avalanches in the North Rockies region including two fatalities.

Meanwhile, the Coquihalla danger ratings are forecasted as considerable in the alpine on Saturday but moderate treeline and below. Sunday is moderate at all elevations.

Avalanche problems consist of storm slabs at all elevations, on all aspects, and are very likely to produce up to size 2.5 avalanches.

The second problem is cornices in the alpine on lee aspects (northwest, north, northeast and east). If cornices do fail they could possibly produce size 1.5-2.5 avalanches.

Avalanche Canada advised that the avalanche forecast could increase to high if more than 20cm fell anywhere in the Southcoast Inland area.

For the full forecast including terrain and travel advice for the region you are going to, as well as further details regarding the snowpack, weather, and avalanche observations and more, visit www.avalanche.ca.

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