Atmospheric river takes rare path, localized flood threat for parts of B.C.

·3 min read
Atmospheric river takes rare path, localized flood threat for parts of B.C.
Atmospheric river takes rare path, localized flood threat for parts of B.C.

The relentless and stubborn storm parade continues to sweep through British Columbia, with the next plume of Pacific moisture taking a more unusual path. Some areas are in line for 75-100 mm of rain through Thursday evening, with rainfall warnings in effect for Victoria, Metro Vancouver, and the Fraser Valley. The southerly track of the low will also allow snow to fall all the way down at pass level, leading to difficult travel along major routes through the interior including the Coquihalla. More on the timing and impacts of this system below, plus a look at a well-deserved break thanks to a recurving typhoon in the west Pacific.

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THURSDAY INTO FRIDAY: ATMOSPHERIC RIVER SET-UP TAKES AIM AT THE B.C. COAST, AGAIN

Special weather statements and rainfall warnings are widespread across B.C., as yet another moisture-laden system with an atmospheric river pattern brings more heavy rain to southern Vancouver Island through Thursday. But this set-up is arriving in an unconventional way.

Flow from the Pacific will thread the needle between the Olympic and Vancouver Island mountains, allowing heavy rain to drench one of the B.C. coast's drier locations -- the provincial capital.

VictoriaRain
VictoriaRain

Rainfall totals near 50 mm will be possible for Victoria, joining only a handful of October rain events from the historical record to reach those totals.

"Although it is unlikely that Victoria will see 50 mm of rain in a day, it happens in these setups, where the atmospheric river bypasses the Olympic Mountains," explains Tyler Hamilton, a meteorologist at The Weather Network. "The mountains don't move, so the only thing changing is the wind direction. It looks to thread the needle between the Vancouver Island range and the Olympic mountains, creating heavier rain for Victoria.

The heaviest amounts of rain are expected in the Fraser Valley and on the island, where rain totals could reach and even exceed 100 mm through Thursday, before easing by the evening.

BCRain (11)
BCRain (11)

"Heavy downpours can cause flash floods and water pooling on roads. Localized flooding in low-lying areas is possible," says Environment and Climate Change Canada in the warning.

Vancouver itself and parts of Metro Vancouver are more in line for 20-40 mm through this event.

The southerly track of the low will also allow snow to fall all the way down at pass level, leading to difficult travel along major routes through the interior including the Coquihalla.

BCPasses (1)
BCPasses (1)

The Coquihalla Pass will notch the highest totals, 10-20 cm, but most other passes will be in the 5-10 cm range.

"Weather in the mountains can change suddenly resulting in hazardous driving conditions," ECCC says in the special weather statement for the Coquihalla Highway.

LOOK AHEAD: MUCH-NEEDED BREAK FROM THE STORMY PATTERN, UNUSUALLY WEATHER PLEASANT HALLOWEEN

Beyond the next system, a much-needed break from the stormy pattern is expected -- with drier weather and sunshine late week and the weekend, lingering into next week. In fact, the break from the stormy pattern for the coast is due in part to a recurving typhoon in the west Pacific.

Abundant sunshine is in store this weekend for the South Coast, with unusually pleasant weather for Halloween.

Be sure to check back for the latest updates on the weather in B.C.

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