US, Canada: Adverse weather forecast in northwestern US and western Canada through at least Nov. 26 /update 12

Event

Further snow and rain are likely in the northwestern US and western Canada through at least Nov. 26. The affected area includes northern Idaho, western Montana, northern Oregon, Washington, and northwestern Wyoming states in the US as well as British Columbia Province and western Yukon Territory in Canada. Additional rainfall could result in flooding or flash flooding on already saturated soil and exacerbate the current situation.

US authorities declared a state of emergency for Clallam, Grays Harbor, Island, Jefferson, Lewis, King, Kitsap, Pierce, Mason, San Juan, Skagit, Snohomish, Thurston, and Whatcom counties in Washington State, US, due to flooding Nov. 15. At least one fatality has been reported southwest of Sumas, Washington due to flooding.

Authorities in British Columbia declared a provincewide state of emergency Nov. 17 due to the risk of flooding and landslides. The state of emergency is in effect for 14 days and can be extended if conditions warrant. Under the state of emergency, armed forces have been deployed to assist local authorities with cleanup operations and maintain supply chains. Vancouver has been particularly affected by flooding. Officials have closed multiple roads and railways throughout the province due to flooding, including major routes into and out of Vancouver. At least four people have died and one other is still missing due to a mudslide on Highway 99 near Lillooet.

In Abbotsford, authorities maintain evacuation orders for portions of Sumas Prairie, and the Straiton area while an evacuation alert is in place for the Clayburn area and the east side of Zurich Drive. Emergency shelters are located at TRADEX (Fraser Valley Trade and Exhibition Centre) and Chilliwack Landing Sports Centre. A boil water advisory is in effect for Sumas Prairie. The Thompson-Nicola Regional District has also ordered residents from parts of electoral areas "I" and "N" to evacuate due to flooding.

Operations at the Trans Mountain pipeline have been suspended since Nov. 13 as a precaution. Almost half of British Columbia's gasoline is supplied by Alberta through the Trans Mountain pipeline. Trans Mountain is currently assessing the condition of the pipeline from the air and ground but access is being hampered by debris and damaged transport networks. Authorities estimate that the pipeline will be restarted in some capacity by Nov. 27. Parkland Corporation is moving to pause the refinery processing operations at Burnaby due to the lack of crude oil supply from the pipeline. The refinery will be maintained in ready-mode so processing can be resumed quickly once crude oil supply is restored. Authorities are limiting the general public to 30 liters of gas per visit to gas stations in the Lower Mainland-to-Hope region, the Sea-to-Sky region, Sunshine Coast, the Gulf Islands, and Vancouver Island through at least Dec. 1.

Residents in British Columbia Province's border communities are allowed to cross the border into the US for gas and other essential goods, and return without a COVID-19 test or quarantining, whether they are vaccinated or not.

Government Advisories
As of late Nov. 23, the US Weather Prediction Center (WPC) has issued a "High Risk" (the second-highest level on a four-tier scale) for heavy snow of at least 10 cm (4 inches) across the Pacific Northwest to the Northern Rockies. Snow levels are likely to drop below 610-915 meters (2,000-3,000 feet) in the northern areas as the rain eases through early Nov. 24, with heavier snow over the Blue Mountains and portions of the Northern Rockies.

The US National Weather Service has issued winter weather advisories over northern Idaho, western Montana, and northwestern Wyoming.

The Meteorological Service of Canada has issued red (the highest level on a three-tier scale) rainfall warnings across Central Coast, North Coast, North Vancouver Island, and West Vancouver Island in British Columbia Province. Red snowfall warnings are in place for South Klondike Highway in British Columbia Province and Whitehorse in Yukon Territory while a red blizzard warning has been issued in Dempster, Yukon Territory.

In British Columbia, authorities are maintaining a flood warning for Sumas River while high streamflow advisories are in effect for the North, Central, and South Coasts as well as Vancouver Island. Authorities will likely issue new alerts or update existing advisories as the winter storm transits the region over the coming days.

Hazardous Conditions
Snow accumulations are likely across the affected area. Lesser accumulations are possible where sleet and freezing rain mix with the snow and the precipitation are less intense. In addition to the heavy snow, strong wind gusts will likely lead to periods of blowing and drifting snow. Blizzard conditions are possible. Sporadic power outages are possible throughout the affected area.

Transport
Multiple sections of highways 1, 5, 8, and 11, as well as many other roads in British Columbia, remain closed due to heavy rain, landslides, and damage. Authorities have reopened portions of highways 1, 3, 5, 7, 11, and 99 but have restricted the highways to nonessential travel only at Highway 99 between Lillooet and Pemberton, Highway 3 between Hope and Princeton, Highway 7 from Agassiz to Hope, and Highway 1 in the Abbotsford-Sumas area and between Popkum and Hope.

The Canadian Pacific Railway has resumed operations between Kamloops, British Columbia and Vancouver Nov. 23 after repair works were completed. The Canadian National Railway is planning to resume limited services between Kamloops and Vancouver Nov. 24. Air Canada has rescheduled 28 passenger flights and is operating an additional 13 all-cargo flights, increasing its cargo capacity in Vancouver by 3,223 cubic meters (586 tonnes) Nov. 21-30, to ease the supply chain disruptions. The airline has also increased the number of available seats for customers in Kelowna and Kamloops to transport those affected by the highway closures. The disruptions to the railways and highways have affected operations in Vancouver; the reopenings are likely to help ease the cargo backlog and supply chain disruptions across British Columbia.

Authorities have prohibited nonessential water travel between Abbotsford and Chilliwack and all aircraft from flying lower than 305 meters (1,000 feet) between Abbotsford International Airport (YXX) and Chilliwack Airport (YCW) to allow for emergency response.

Additional traffic and commercial trucking delays are possible along regional highways. Difficult and dangerous driving conditions are also likely on secondary and rural roads in the affected states as maintenance crews prioritize clearing major routes. Flight delays and cancellations are likely due to ground stops and deicing operations at regional airports.

Advice

Monitor local media for updated weather information. Verify road conditions before driving in areas where heavy snowfall is forecast. Allow extra time to reach destinations in these areas and carry an emergency kit and warm clothes if driving is necessary, especially on secondary or rural routes that could become impassable. Plan accordingly for delivery delays if routing shipments by truck through the affected area through at least Nov. 26. Confirm flights. Charge battery-powered devices in the case of prolonged electricity outages.

Resources

US National Weather Service
US Road Conditions
Meteorological Service of Canada
DriveBC