Skip to content

Avalanche danger still considerable for Rocky Mountains

According to the avalanche bulletin put out by Parks Canada, moderate to strong winds and new snow over the next couple days will build wind slabs in lee areas at treeline and above – and if triggered, the wind slabs may step down to deeper layers and result in large slides
20190219 EEOR Avalanche Control 0002
Kananaskis Public Safety performs avalanche control on the east end of Rundle Mountain after a significant snowfall near Canmore earlier this year. RMO FILE PHOTO

BANFF – A widespread special avalanche warning that included Kananaskis Country and mountain national parks was lifted earlier this week, but avalanche forecasters still warn backcountry enthusiasts to be careful out there.

As of New Year’s Day (Wednesday, Jan. 1), the avalanche danger in Banff, Yoho and Kootenay national parks as well as Kananaskis Country was considerable in the alpine and at treeline, and moderate below treeline.

According to the avalanche bulletin put out by Parks Canada, moderate to strong winds and new snow over the next couple days will build wind slabs in lee areas at treeline and above.

“These will be easy to trigger, so avoid lee loaded areas and minimize your time in areas with wind loading going on above you,” according to the bulletin on Dec. 31.

“If triggered, the wind slabs may step down to deeper layers resulting in large avalanches.”

A major four-day snowstorm that began on Dec. 20 led to a widespread special avalanche bulletin for B.C. and Alberta, including the mountain national parks and Kananaskis Country. The special warning was lifted Sunday (Dec. 29).

An Atmospheric River, also known as a Pineapple Express, brought heavy snow to parts of southwestern Alberta beginning Friday, Dec. 20 and continuing through until Monday morning, Dec. 23.

According to Environment and Climate Change Canada, this system first made landfall on the British Columbia side of the Rocky Mountains, causing road closures, countless vehicle collisions, and elevating avalanche risk across the Rockies in Alberta and B.C..

The storm dropped a significant amount of snow, resulting in many avalanches that ran to historic run-outs.

In fact, an avalanche hit and derailed a Canadian Pacific train in Glacier National Park, east of Revelstoke, B.C., about 8:30 p.m. on Dec. 21. The line was reopened Sunday night once all track repairs and safety inspections were complete.

“Seven intermodal platforms derailed as a result of the avalanche,” said CP spokeswoman Salem Woodrow in an email. “There were no injuries to the crew.”

Sarah Hoffman, a meteorologist with Environment and Climate Change Canada, said between 55-79 cms fell in the Lake Louise region at the height of the storm, while the Nakiska ski area and Kananaskis Village area saw about 56-75 cms.

She said the areas surrounding the Banff townsite and Canmore saw similar amounts of snowfall – 40-64 cms and 40-66 cms respectively.

Hoffman said snowfall data isn’t very robust and snowfall records end around 2005 for the Banff area; however, noted there were several cases where more snow fell in a 24-hour period in this region than this most recent snowstorm.

“The number one heaviest snowfall in a 24-hour period occurred on Dec. 14, 1979 when 58.6 cm fell,” she said.

“The number two heaviest snowfall in a 24-hour period occurred on Nov. 19, 1892 when 53.3 cm fell.”

Hoffman said the snowstorm was a result of the Atmospheric River, or Pineapple Express, in which a plume of warm moist air led to the major snow dump across a broad region.

“That’s absolutely not unusual and happens quite often; though the magnitude of this atmospheric river may have been a little bit stronger than normal,” she said.

“The strong westerly push of warm moist air is a typical winter experience for the mountains, but these dumps of snow seem a bit unusual because in parts of southern Alberta, it’s the spring that’s most prone to these heavier dumps of snow.”

Meanwhile, Avalanche Canada, Parks Canada, and Kananaskis Country warn all backcountry users and anyone recreating in avalanche terrain, including those going outside ski area boundaries, to always check their regional avalanche forecasts at www.avalanche.ca.

They say everyone in a backcountry party needs the essential rescue gear – transceiver, probe and shovel – and the knowledge to use it. Ensure your party re-groups well away from avalanche slopes, including overhead hazard such as cornices.



Comments


About the Author: Cathy Ellis

Read more