Hefty alpine snow raises avalanche risk in B.C., Christmas chill looms

·4 min read
Hefty alpine snow raises avalanche risk in B.C., Christmas chill looms
Hefty alpine snow raises avalanche risk in B.C., Christmas chill looms

After a icy night across parts of the Lower Mainland and Vancouver Island in B.C. Tuesday, making for slippery roads and dicey travel, precipitation has changed over to rain Wednesday morning as warmer air has bumped up temperatures amid the track of the current low. Some areas could see accumulative rainfall totals of 50-75 mm through Thursday, while the mountain passes are in the midst of a sluggish storm that will bring local totals of 30-50 cm during the same time. As a result, the avalanche danger ratings have been raised in the mountain passes Wednesday. Looking further ahead, a blast of cold air could lead to one of the coldest Christmases on record in places like Vancouver. More on the timing and impacts, below. Could see

MUST SEE: Canada's 2021 Holiday Snow Report

WEDNESDAY/THURSDAY: LOWS MERGE TO BRING MORE RAIN, AND MOUNTAIN SNOW

The icy part of the current system, two lows merged as a single storm, has ended, with warmer air moving in and transitioning precipitation to rain for the Lower Mainland and Vancouver Island by early Wednesday morning.

In terms of accumulative rainfall amounts from the systems, the Lower Mainland can expect between 30-60 mm of rain through Thursday, with higher totals possible in areas where terrain enhances precipitation rates. 50-75 mm is anticipated for the eastern Fraser Valley and southwestern Vancouver Island.

BCRAIN
BCRAIN

Meanwhile, widespread winter storm warnings are in place for a slow-moving winter storm that will continue to trek across the southern B.C. Interior Wednesday. Heavy snow will continue before tapering off to flurries by Thursday morning.

Locally 30-50 cm of snow is forecast across the mountain passes and parts of the Rockies through Thursday. Weather in the mountains can change suddenly resulting in hazardous driving conditions.

BCSnow
BCSnow

"Surfaces such as highways, roads, walkways and parking lots may become difficult to navigate due to accumulating snow. Rapidly accumulating snow could make travel difficult over some locations. Visibility may be suddenly reduced at times in heavy snow," Environment and Climate Change Canada (ECCC) says in the winter storm warning.

In addition to the wintry precipitation, winds will remain blustery into Wednesday evening before dissipating in the overnight. Gusts of 50-70 km/h are expected for coastal and Interior regions. However, winds along the northern Vancouver Island coast will ramp up again Thursday afternoon.

As a result of the mountain snow and what is already on the ground, the avalanche danger is raised across the passes Wednesday. Danger ratings will range from moderate to high. People are being asked to avoid the backcountry, ranging in altitudes from the alpine to below the tree line.

BCAvalanche
BCAvalanche

LOOKING AHEAD: UNUSUAL AND EXTENDED STRETCH OF ARCTIC AIR WITH POTENTIALLY RECORD BREAKING COLD

Arctic air, potentially dangerous, will spread over Western Canada late week and on the Christmas weekend, with an unusual and extended stretch of Arctic air set to blast B.C.

BCFreezingLevels
BCFreezingLevels

While freezing levels for the South Coast will temporarily bump up mid-week with the arrival of the system, freezing levels are forecast to bottom out on Sunday and beyond, with daytime high temperatures for Vancouver sitting near the freezing mark for Christmas.

Vancouver actually has the potential of breaking records with this cold. A daytime high of 0°C is currently forecast for Saturday (Christmas Day). The coldest daytime high recorded on Christmas for Vancouver was -1.7°C tied in 1924, 1964 and 1971.

Whatever the final temperature is, it will be one of the coldest Christmases, and also Boxing Days, on record for the Vancouver area.

BCTEMPSAT
BCTEMPSAT

This extraordinary stretch of frigid weather expected for the South Coast will continue through the end of the month, with additional opportunities for snow, rain and even mixing at times.

Thumbnail courtesy of DriveBC.

Check back for the latest forecast across British Columbia.

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