Ministry of FLNRO

Flood Warnings and Advisories

High Streamflow Advisory - Somass River, Cowichan River (MAINTAINED)
ENDED - High Streamflow Advisory – Southern Vancouver Island
ISSUED: November 24, 2017 11:15 AM

The River Forecast Centre is maintaining a High Streamflow Advisory for:

  • Somass River including Sproat River, Stamp River and tributaries

The River Forecast Centre is ending a High Streamflow Advisories for:

  • Southern Vancouver Island including the Nanaimo River, Chemainus River Koksilah River and surrounding areas except Cowichan River

Rain and snowmelt earlier in the week has now passed through river systems in the region. Flows are expected to continue to recede Friday and into the weekend. With lake influence in the Cowichan and Sproat/Somass Rivers, levels are expected to drop slowly. Additional rainfall is expected over the weekend, and additional rises in river levels are possible. Preliminary hydrologic modelling for the Somass River is indicating the potential for higher flows Sunday and Monday than have been experienced over this past week. Current projections indicate the potential for estimated flows on the Somass River of approximately 800 m3/s, or similar to 2015 flood levels.

The River Forecast Centre will continue to monitor conditions and update this advisory 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.