Up to 80 millimetres of rain expected in parts of Lower Mainland several days after catastrophic floods

A special weather statement has been upgraded to a rainfall warning in Metro Vancouver and the Fraser Valley, with forecasts estimating up to 80 millimetres could fall across parts of the region.

The warning is in effect from Wednesday night through to the end of the day Thursday. Howe Sound is also covered by this advisory.

People in these regions are being told the next storm system, which has been described as another atmospheric river, will bring the heaviest rain on Thursday as it moves south across the coast.

CityNews Meteorologist Michael Kuss says the precipitation will be light through Wednesday — it’s Thursday we need to watch.

“It’s overnight. Tomorrow, kind of mid-morning and then into the early afternoon — that’s the bullseye for the heaviest precipitation in that window, around mid-day, but potentially even into the afternoon drive,” he said. “That piles up to 40 to 80 millimetres, potentially, around the area.”

Rain will be quite light today. May not get 3 mm Wednesday. Heavy rain runs all Thursday. 40-80 mm in about 24 hours. @CityNewsVAN pic.twitter.com/fqcxVUHh5n

— Michael Kuss (@Kusswx) November 24, 2021

Those estimates are predominantly for the Metro Vancouver region. Kuss says the Fraser Valley is expected to see rainfall in the “30 to 60+ millimetres.”

The rain, of course, comes as many communities, including Abbotsford, continue to struggle with flooding, more than a week after a more severe atmospheric river swept across the region.

While the last atmospheric river brought catastrophic consequences to much of southern B.C., this storm system is not expected to be as severe.

Areas in the B.C. under a high streamflow advisory include Sea to Sky country, the Sunshine Coast and the Howe Sound.

There’s also a flood warning in place for the Sumas Prairie and surrounding areas. Rivers out there can expect water levels they haven’t seen in a couple of years.

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A key difference between the two is the length — what we are expecting Thursday is not set to last longer than about 24 hours, while the destructive rain that caused flooding and mudslides last week lasted days.

“It’s a pretty long swath. No, we’re not talking about two days, two and a half days, but we’re still looking at a full day of rain,” Kuss said of Thursday’s system.

Forecasters are also warning of strong winds, especially near the water.

More rain is on the way..
The next storm system is set to arrive on the South Coast overnight Wed. This storm will be shorter lived and less intense than the event over Nov. 13-15, 2021. However, it will still bring moderate to heavy rain and strong winds. https://t.co/SfBUD0q3UQ

— ECCC Weather British Columbia (@ECCCWeatherBC) November 23, 2021

Environment Canada says freezing levels will also rise “above mountain tops,” which has the potential to “worsen recent flooding and impact vulnerable landscapes and infrastructure.”

People are being told to avoid getting close to washouts near rivers, creeks, and culverts.

In Abbotsford, the mayor has also urged people to prepare an emergency kit that is stocked with at least 72-hours worth of supplies.

“It’s also important to ensure that your vehicles are fueled and parked in an area that will allow you to evacuate quickly, if required. If you are looking to protect your property right now, sand and sandbags are available at both Albert Dyck Park and Yarrow Hardware,” Henry Braun said Tuesday.