Significant precipitation continues to overspread coastal and southern portions of British Columbia this morning as the last in a series of atmospheric rivers affects the region. A slew of rainfall warnings, snowfall warnings, and special weather statements are in effect as the moisture washes over the province. The precipitation could lead to additional flooding, mudslides, and avalanches, potentially exacerbating an already precarious situation. More on the details and timing for this event, below.
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TUESDAY-WEDNESDAY: ATMOSPHERIC RIVER UNLEASHES EXCESSIVE RAINFALL
Steady rain began falling over coastal and southern portions of B.C. early Tuesday morning as the latest atmospheric river moved into Western Canada. This is the third atmospheric river to affect the region in the past week.
Moisture associated with this atmospheric river originated 8,000 km away in the Philippines. The vapour’s long trek across the Pacific will end with significant rainfall at lower elevations and snow at higher elevations across the southern half of B.C., leading to a risk for further flooding, mudslides, and avalanches across the region.
The current and final atmospheric river won’t be as impactful for the Lower Mainland. Its west-to-east orientation will allow Vancouver Island to wring out much of the moisture before it reaches the Lower Mainland.
Widespread rainfall totals of 40 to 120 mm are expected by the end of the storm. The highest totals are likely on western Vancouver Island and at higher elevations, where 100-200+ mm of rain is possible. Storm totals of 40-70 mm are possible around Metro Vancouver.
Environment Canada and Climate Change (ECCC) has issued special weather statements and rainfall warnings for the North, Central and South coasts, as well as the Lower Mainland.
“Heavy downpours can cause water pooling on roads. Localized flooding in low-lying areas is possible. Rising freezing levels and snowmelt may contribute to increased runoff,” ECCC said in its statement.
Low freezing levels allowed precipitation to begin as snow across alpine regions on Tuesday morning. Snowfall warnings are in effect for Fort Nelson and the Yellowhead, while winter storm warnings are in effect for inland sections of the North Coast, including Stewart.
Runoff from snowmelt and a risk for avalanches will become a concern through Wednesday as freezing levels quickly rise. Continued snowmelt will further swell B.C.’s rivers, exacerbating the risk for flooding at lower elevations.
The avalanche danger rating is high at all elevations for ranges on Vancouver Island, the South Coast, and Interior sections on both Tuesday and Wednesday. An extreme avalanche danger exists at the alpine level across Sea to Sky and the North Rockies, according to Avalanche Canada.
B.C. EXTENDS FUEL RESTRICTIONS INTO MID-DECEMBER AS FLOOD THREAT CONTINUES
THURSDAY AND BEYOND: A BRIEF BREAK BEFORE THE NEXT UNSETTLED WEATHER
Calmer conditions will arrive in B.C. to end the week as a ridge of high pressure builds over the region. Sunshine and seasonal temperatures will prevail across Metro Vancouver on Thursday and Friday.
The break will prove short-lived, though, as another storm will reach B.C. this weekend. This system looks much weaker than what the region has had to contend with for the past couple of weeks. However, falling freezing levels could bring a threat for low-elevation snow on Saturday.
Check back for the latest on the heavy rain and avalanche danger across British Columbia.Internet Explorer Channel Network