B.C.’s River Forecast Centre has issued high streamflow advisories for all of coastal B.C.
The centre issued the three advisories Friday (March 13) at 11:30 a.m.: for the north and central coasts, Vancouver Island and the south coast.
A strong atmospheric river is forecast to hit coastal B.C. beginning midday on Sunday (March 15) and could potentially continue on for several days. The heavy rainfall could continue through to Wednesday or longer.
Freezing levels are expected to rise quickly and additional runoff from snowmelt is expected.
The advisory adds that “uncertainty remains regarding the exact duration and intensity of the atmospheric river.” The forecast models also call for “multiple pulses” of rainfall, which could “extend the period of elevated runoff and river response through the middle of next week or longer.”
Localized river high flows are expected due to heavy rainfall and rain-on-snow runoff throughout the north and central coasts.
“Smaller rivers and streams may respond quickly to intense rainfall and could experience rapid rises during periods of heavy precipitation,” the advisory warns.
North and central coasts
The advisory for the north and central coasts include Prince Rupert, Kitimat, Terrace, Bella Coola, Rivers Inlet and surrounding areas and other coastal communities.
Environment Canada has forecast up to 200 millimetres of rain from Sunday to Wednesday, including:
• 100 to 200 millimetres for Prince Rupert
• 100 to 200 millimetres for Kitimat
• 100 to 200 millimetres for Bella Bella
• 100 to 175 millimetres for Bella Coola
• 100 to 200 millimetres for Kingcome Inlet
South coast
The warning for the south coast includes the North Shore mountains, Metro Vancouver tributaries, Howe Sound, the Sea-to-Sky corridor, including Squamish and Pemberton, the Sunshine Coast and Lower Fraser tributaries and the Fraser Valley.
Environment Canada has forecast up to 200 millimetres of rain from Sunday to Wednesday, including:
• 150 to 200 millimetres for Howe Sound and the Sea to Sky
• 60 to 120 millimetres for Metro Vancouver
• 120 to 180 millimetres for the North Shore mountains
• 60 to 120 millimetres for the Fraser Valley
• 30 to 60 millimetres for Whistler and Pemberton
Vancouver Island
The entire Island is covered by the advisory.
Environment Canada has upward of 300 millimetres of rain from Sunday to Wednesday, including:
• 100 to 120 millimetres for north Vancouver Island
• 200 to 300-plus millimetres for west Vancouver Island
• 100 to 150-plus millimetres for inland Vancouver Island
• 50 to 100-plus millimetres for east Vancouver Island
• 30 to 60 millimetres for Greater Victoria