Flood Warnings and Advisories

High Streamflow Advisory – Vancouver Island
UPDATED: 11:20 AM November 26, 2018

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

  • West Vancouver Island – including tributaries around Gold River, Zeballos, Tofino and surrounding areas
  • Central Vancouver Island – including the Sproat and Somass Rivers and areas surrounding Port Alberni
  • East Vancouver Island – including tributaries around Campbell River, Courtenay, Parksville, Nanaimo and surrounding areas
  • Southern Vancouver Island – including the Cowichan River, Chemainus River and surrounding tributaries

A series of intense Pacific storms is impacting the South Coast and Vancouver Island. Heavy rain has occurred overnight and this morning across the region, and is expected to continue through the day on Monday. Observed rainfall totals so far have been in the 50-150 mm range on the west side of Vancouver Island, and in the 40-75mm range in other areas of the central, eastern and southern Vancouver Island.
Rivers have been responding to this rainfall. A summary of current conditions includes:

  • Tofino Creek near the mouth (Water Survey of Canada gauge 08HB086) peaked earlier this morning at approximately 220 m3/s (between a 2-year and 5-year return period flow), and is currently receeding
  • Oyster River below Woodhus Creek (WSC 08HD011) is currently flowing at 55 m3/s and rising. Flows are currently forecast to reach up to approximately 250 m3/s (2-year to 5-year flow), and potentially higher by later on Monday or into Tuesday
  • Cowichan River near Duncan (WSC08HA011) is currently flowing at approximately 70 m3/s, and is forecast to reach up to 350-400 m3/s (5-year flow) on Tuesday

Heavy rain is expected to continue throughout the day today. Environment and Climate Change Canada have issued rainfall warnings for the region, indicating the potential for 60-80 mm of rainfall through Tuesday morning, and amounts up to 90-120 mm over higher terrain.
River levels are expected to rise rapidly in response to this rainfall throughout Monday and overnight into Tuesday. Shallow snow accumulations at mid-elevations over the past few days are expected to melt with warmer temperatures, and will contribute additional runoff to streams. Additional heavy rainfall is expected to continue throughout the day. Peak flows are expected late Monday and into Tuesday.
As the storm passes throughout the day, there will be increased certainty over rainfall amounts and the locations which have the greatest risk of high flows. Key areas of concern with the current forecast include the Cowichan River, Chemainus River, Englishman River, San Juan River, and areas surrounding Duncan, Nanaimo, Port Alberni, and Parksville. High flows are expected in these areas and throughout Vancouver Island.
This advisory will be upgraded later today if there becomes an increased concern over the potential for flooding in specific areas.
The River Forecast Centre will continue to monitor conditions and update this advisory as conditions warrant.

Contact for Media Relations, Ministry of Forests, Lands, Natural Resource Operations and Rural Development:
Tel: 250 356-7506

Levels of Warnings/Advisories:

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

Links:

  1. Home of River Forecast Centre
  2. Current Streamflow Conditions and Flood Forecast Modeling
  3. Map of Current Streamflow Return Periods for All WSC Stations
  4. CLEVER Model 10-day Forecasts of Discharges and Return Periods
  5. COFFEE Model 5-day Forecasts of Discharges and Return Periods
  6. Back to page of Flood Warnings and Advisories