Flood Watch for Sea to Sky and Howe Sound

Nov 15, 2021
Affected Communities: 
District of Squamish, Electoral Area C, Electoral Area D

The Ministry of Forests, Lands, Natural Resource Operations and Rural Development has issued a Flood Watch for several parts of the province, including the Sea to Sky and Howe Sound.

A significant atmospheric river has made land fall across southern coastal regions of British Columbia.

Observed rainfall amounts since yesterday have been in the 100-140mm range through Howe Sound, North Shore Mountains, and Sunshine Coast; 90-160mm in the Fraser Valley – East, Fraser Canyon and areas around Hope and Harrison Lake.

Environment and Climate Change Canada have continued rainfall warnings in effect across the region.

Rainfall is expected to taper off by Monday afternoon.

Snowmelt is being observed at mid-elevations and is expected to add additional runoff to rivers. Rivers have risen rapidly from rainfall since yesterday.

Current conditions include:

  • Chilliwack River above Slesse Creek (08MH103) have reached 375 m3/s (approaching a 20-year flow). Additional increases are possible through the day on Monday
  • Chilliwack River at Vedder Crossing (08MH001) reached a high of approximately 490 m3/s overnight and has dropped through Monday morning
  • Coquihalla River above Alexandra Creek (08MF068) is flowing at approximately 550 m3/s (between a 10-year and 20-year flow) and has leveled over the past few hours. Additional rises are possible through the day on Monday
  • Stawamus River at Highway 99 (08GA076) is flowing at 85 m3/s (between a 2-year and 5-year flow) and rising at approximately 15 m3/s per hour

Rivers through the region are expected to remain high through Monday morning, with improvements expected Monday afternoon as rainfall eases.

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

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

  • A High Streamflow Advisory means that river levels are rising or expected to rise rapidly, but that no major flooding is expected. Minor flooding in low-lying areas is possible.
  • A Flood Watch means that river levels are rising and will approach or may exceed bankfull. Flooding of areas adjacent to affected rivers may occur.
  • A Flood Warning means that river levels have exceeded bankfull or will exceed bankfull imminently, and that flooding of areas adjacent to the rivers affected will result.

To report severe weather, send an email to BCstorm@ec.gc.ca or tweet reports using #BCStorm.

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