Latest atmospheric river prompts extreme avalanche warning in B.C.'s Sea to Sky region

Some of southern B.C.'s alpine regions are under an extreme avalanche warning as the latest atmospheric river is expected to raise freezing levels on local mountains.

Avalanche Canada issued a noticed late Monday afternoon saying the extreme warning is in place for alpine levels in the Sea to Sky region for Tuesday and Wednesday. Extreme is the highest rating on the agency's five-tier system.

"Another atmospheric river storm will bring lots of precipitation and rising freezing levels. As a result, expect to see a widespread avalanche cycle with the potential for large, full-path avalanches," the warning said.

"Avoid all avalanche terrain for the next days."

Avalanche Canada said "surprising large avalanches" have already been reported in the area over the past few days, and the incoming intense storm may lead to more activity.

"We are confident the likelihood of avalanche will increase with the arrival of the forecast weather," Avalanche Canada's warning said.

The lower areas in the region – treeline and below treeline – are under a high avalanche warning. The danger levels are expected to fall lower on Thursday.

In the South Coast region, which includes the North Shore mountains, the danger for avalanches in the alpine areas is rated as high. By Thursday, it's expected to be low.

"The next two days are a good time to be extra careful, even when walking on familiar, local trails," Coquitlam Search and Rescue said on social media about the avalanche warnings and incoming rain.

"We're experiencing unusual conditions and the ground has been saturated already."

B.C. is bracing for its third atmospheric river in less than a week to arrive on Tuesday, delivering more heavy rain to communities that remain flooded from previous storms. Officials have warned warmer temperatures will raise freezing levels on the mountains, which could lead to more snow melt and exacerbate flood conditions.