Intense atmospheric river targets B.C. with multi-day, heavy rainfall
A strong-rated atmospheric river is expected to bring significant, prolonged rainfall to British Columbia through next week, creating a dangerous combination of raised flood and avalanche risks.
B.C. faces intense rainfall over a multi-day stretch as a strong and unusually late-season atmospheric river berates the coast.
Expected to rank as an AR3 or AR4 event, the result to B.C. is a heightened avalanche danger and a rising flood threat. It's unusual to have such a potent atmospheric river for mid-March. Most of the affairs tend to happen in mid-fall and early winter.
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Some areas could see 75 mm-300 mm of rain. Expect extensive water pooling on roads and washouts may occur, so there could be road closures and difficult travel with the rainfall.
Pineapple express expected through much of next week
A pineapple express is an atmospheric river that originates near Hawaii. This deep, rich plume of tropical moisture can fuel heavy rainfall and rising freezing levels across southwestern B.C.
There has been lots of lower-elevation snow in elevations 400-1200 metres over the past week, increasing run-off with snowmelt.
Given its strength and predicted longevity, forecasters anticipate this upcoming pineapple express event to rank an AR3 or AR4, which means this type of event is often hazardous with river flooding impacts possible. Some areas could see the atmospheric river endure for more than 72 hours.
Sunday afternoon initially features low snow levels on Vancouver Island and the Lower Mainland, with wet snow above 300 metres in elevation.
This surge of moisture tracking northeast directly from Hawaii will fuel heavy rainfall beginning late Sunday and continuing into next work week.
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Rainfall forecast
Tofino: 200-300 mm
North Shore Mountains: 150 mm-200 mm
Squamish: 150 mm-200 mm
Campbell River/Comox Valley: 75 mm
Nanaimo: 50-75 mm
Victoria: Approximately 50 mm
Lower Mainland (south of Fraser River: 75 mm-100 mm)
North of Fraser: 100-150+mm
In addition to the heavy rainfall, we’ll also see freezing levels spike to more than 2000 metres by Monday, a rise that will last through the week.
Monday's avalanche danger is forecast to be high near Whistler, with up to 60 cm of recent snowfall and gusty winds creating wind-loaded areas.
Significant snow that fell through the beginning of the month will begin to melt next week with the arrival of warmer temperatures.
The combination of heavy rainfall and snowmelt will likely elevate flood alerts throughout the region during the days ahead.
Pay close attention to forecasts and alerts for your area in the coming days.
Stay with The Weather Network for all the latest on conditions across B.C.