Ministry of FLNRO

Flood Warnings and Advisories

Flood Warning - Somass River (MAINTAINED)
ISSUED: November 27, 2017 11:00 AM

The River Forecast Centre is maintaining a Flood Warning for:

  • Somass River including Sproat River, Ash River and tributaries

A series of frontal systems moved over Vancouver Island last week and over the weekend, saturating the soil in this area and causing lake levels to increase considerably.

  • The ASH RIVER BELOW MORAN CREEK (08HB023) has dropped since peak levels yesterday and is currently flowing at 160 m3/s, which is below a 2-year return period flow
  • SPROAT RIVER NEAR ALBERNI (08HB008) has dropped slightly since yesterday, and is currently flowing at 245 m3/s (2-year to 5-year flow)
  • SOMASS RIVER NEAR ALBERNI peaked at an estimated flow of 870 m3/s yesterday, and is currently estimated to be flowing at 770 m3/s (2-year to 5-year flow)

River levels will continue to see modest improvements through most of Monday. Environment and Climate Change Canada (ECCC) is currently forecasting additional rainfall later on Monday and overnight, with total amounts in the 30-40 mm range for Port Alberni and area. Current hydrologic modeling is indicating the potential for additional rises from this rainfall late-Monday and into Tuesday with peak levels estimated on the Somass River near Alberni reaching up to 800-950 m3/s.


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.