Atmospheric river to bring heavy rains to B.C.'s South Coast

The province is warning over hundreds of millimetres of rain is forecast to fall across B.C.'s South Coast starting on Saturday and lasting until Wednesday.

Officials with the Emergency Management and Climate Readiness ministry issued a bulletin on Thursday evening encouraging residents to prepare for the impending storms.

"Heavy rainfall, combined with mountain snow melt, may lead to pressure on B.C.'s river systems and potential flooding," it said. "Additionally, saturated soils combined with strong winds may result in tree damage and power outages."

It says forecasters with Environment and Climate Change Canada expect West Vancouver Island and the Coast Mountains could receive up to 300 millimetres of rain over five days, from Saturday Jan. 27, to Wednesday, Jan. 31.

Atmospheric river

The forecast says that Howe Sound area could receive as much as 250 millimetres of rain, while Inland Vancouver Island and parts of the Fraser Valley could receive 150 and 120 millimetres respectively.

The narrow bands of heavy precipitation coming to B.C. are also known as "atmospheric rivers,'' which occur frequently in the fall and winter in B.C.

WATCH | What is an atmospheric river? 

What is an atmospheric river?

2 years ago

Duration 1:23

It's a term that became more widely known after record-setting flooding hit B.C. in November 2021, but as meteorologist Johanna Wagstaffe explains, atmospheric rivers are not new to west coast of North America.

Flood watches are currently in place for the South Coast, Fraser Valley, and Vancouver Island due to the expected weather.

The River Forecast Centre has also issued a high streamflow advisory for Lower Fraser River tributaries including areas around Pemberton and Lillooet River tributaries, those east around Abbotsford and Hope and to the Fraser Canyon.

A flood watch is the second level on the provincial forecast centre's three-tiered warning system. It means that river levels are rising, and flooding in areas adjacent to riverbanks may occur.

B.C. faced similar conditions in early December when an atmospheric river brought more than 130 millimetres of rain to parts of Vancouver Island and more than 100 millimetres of rain to the Sunshine Coast.

In November 2021, a historic atmospheric river made landfall in B.C. as nearly a month's worth of rain pounded down on the province in less than 48 hours.

It resulted in homes flooded to their upper levels, mass evacuations and thousands of animals lost. Every highway connecting the Lower Mainland to the rest of the province was badly damaged or destroyed during the event.