Flood Warnings and Advisories
Flood Watch - Somass River (UPGRADED)
ISSUED: November 25, 2017 17:00 PM
The River Forecast Centre is upgrading a Flood Watch for:
- The Somass River including the Sproat River, Ash River and tributaries
A storm cycle over Vancouver Island last week has saturated the soil in this area and caused lake levels to increase considerably. The river levels are currently rising slightly. Heavy rainfall about 60 mm is forecast for the Somass River area Saturday night through Sunday. Current hydrologic modelling indicates that the streamflow of the Somass River is expected to rise to approximately 800 m3/s, or similar to 2015 flood levels. The streamflow for the Sproat River is expected to rise to 300 m3/s, which is a 5 to 10-year return period flow.
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.