Environment and Climate Change Canada has issued an unprecedented “red alert” for parts of British Columbia as the province braces for additional rain totals of 4 to 6 inches this weekend, falling on ground already saturated by last week’s storms.
CTV News Canada is reporting that meteorologist Armel Castellan, speaking at a technical briefing Friday, said some weather stations – including those in Victoria, Vancouver, and Abbotsford – have recorded their wettest-ever fall seasons.
“The red level (alert) is something new that we have not issued (before),” Castellan said. “In fact, probably 10, 20 years ago when I started this career, this would be something that we may not see in a given career.”
Looking back to earlier this summer, Castellan said that in hindsight, he would have wanted to issue a red alert ahead of the heat dome that ended up killing nearly 600 people across B.C.
A level 4 atmospheric river is forecast through Sunday
A level 4 atmospheric river is categorized as “mostly hazardous, but also beneficial” according to the Center for Western Weather and Water Extremes (CW3E). This means that flooding and landslide hazards could pose a threat across the region, however, the amount of heavy rain could also be beneficial for drought conditions or for filling reservoirs.
As for Washington state and British Columbia, where people are still recovering and assessing the damages to the region from an unending succession of atmospheric rivers, the additional precipitation will only add to the problem.
This weekend’s atmospheric river event is the second in a series of three storms, the first brought rain to the Pacific Northwest on Thanksgiving Day and the third is forecast to impact the region by Tuesday.
“Due to high forecasted freezing levels and moist soil conditions caused by the multiple [atmospheric rivers] during 10 to 16 November, a large portion of the precipitation could lead to runoff, exacerbating [flood] impacts,” the CW3E warns.
The heaviest rain is forecast to fall on the Olympic Peninsula and southern Vancouver Island, along with the northern Cascades into Canada. By Monday morning, there can be 4 inches to 6 inches of rain total in these areas.
Elsewhere, from northwestern Oregon to north of Terrace, British Columbia, a widespread 1 inch to 2 inches of rain is expected, including in Seattle.
Vancouver could receive 2 inches to 4 inches, while areas to the east that were recently decimated by flooding and landslides are likely to border on the higher amounts.
Rain can continue early next week, as the next storm that poses a serious flooding risk is set to arrive Monday night. This system is expected to steer northward, dropping less rainfall in cities such as Seattle but bringing more rain to places such as Vancouver into Wednesday morning.
