B.C.’s South Coast is set to experience the first significant rainfall of the season.
Global BC meteorologist Kristi Gordon said the atmospheric river is likely to arrive on Friday night and last until Sunday morning. However, not all areas will receive heavy rain the entire time.
Rainfall amounts could range from 80 to 175 millimetres across the North Shore mountains with only 40 to 80 millimetres expected across southern regions of the Lower Mainland. The atmospheric river’s projected strength, which is the amount of moisture and duration, could be between one and two across the Lower Mainland, Gordon added. One means primarily beneficial while two means mostly beneficial but also hazardous.
Gordon explains, “The timeline of the heaviest precipitation for each region is evolving. However, this is our most up-to-date timing.”
Light to moderate rain is expected across the Lower Mainland and South Vancouver Island on Friday. The rain will intensify Friday night and be heavy through Saturday morning. This region may see a lull in the action Saturday afternoon and evening before it picks up again on Sunday.
The outer coast of Vancouver Island will receive the most rainfall with 150 to 250 millimetres of rain in the forecast, Gordon explained. The projected strength of the atmospheric river in this region could reach level four, which means mostly hazardous but also beneficial.
The heaviest rain across the outer coast of Vancouver Island will hit on Friday. The rain may ease on Saturday and return again on Sunday.
The B.C. River Forecast Centre has issued Flood Watches and High Streamflow Advisories.
A Flood Watch is in place for:
- Central Coast including the Kingcome River and Owikeeno River
- South Coast including the Sunshine Coast, Howe Sound, Sea-to-Sky and tributaries around Sechelt, Squamish, Whistler and surrounding areas
- Lower Fraser Tributaries including the Lillooet River and rivers around Pemberton,
- Metro-Vancouver, Lower Mainland and Fraser Valley
- Vancouver Island
The River Forecast Centre is issuing a High Streamflow Advisory for:
- North Coast including tributaries around Stewart, Ging̱olx, Laxg̱̱altsʼap, Gitlaxt’aamiks (New Aiyansh), Prince Rupert, and other coastal communities
- Interior Mountains including tributary rivers in the Upper Fraser, North Thompson, South Thompson, Cariboo Mountains, and Upper Columbia
This atmospheric river, even if it does peak at 120 mm of rain, is still much less than the almost 300 mm that fell in the Upper Fraser Valley in 2021.