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High Streamflow Advisory (Downgraded) for Sea to Sky

Posted on December 02, 2021

As of 3:30pm, Thursday, December 2, 2021, the River Forecast Centre is Downgrading to a High Streamflow Advisory for the South Coast including:

  • Sea-to-Sky including areas around Squamish, Whistler and Pemberton

 

The public is advised stay clear of fast-flowing rivers and potentially unstable riverbanks during the high-streamflow period.

The third in a series of atmospheric rivers ended in the early hours of Dec 2, 2021. This system dropped 70-165 m of rain in the Sea to Sky and Howe Sound area, 120-190 mm of rain on Metro Vancouver’s North Shore, and 30-90 mm of rain in the Fraser Valley and Fraser Canyon. This third system was also a very warm system, melting up to 20 – 50 mm of snow water equivalent at elevations up to 1600 m throughout the region. Systems peaked late yesterday, December 1st, and into the early morning of today (Thursday December 2nd).

Peak flows observed include:

  • The Lillooet at Pemberton river (08MG005) peaked at 442 m3/s, less than a 2-year return period flow.

The short-term outlook is for limited precipitation as well as falling temperatures, favouring snow rather than rain for most elevations. This weather forecast is favourable for the continued recession of streams throughout the region; however, this high streamflow advisory recognizes that streams are still flowing at high volumes as they recover from a quick succession of storms.

Details of the COFFEE and CLEVER Model forecasts can be found at: http://bcrfc.env.gov.bc.ca/fallfloods/map_coffee.html, and http://bcrfc.env.gov.bc.ca/freshet/map_clever.html

The River Forecast Centre continues to monitor the conditions and will provide updates as conditions warrant.

To receive emergency notifications, sign up for Pemberton Alert.

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