High Streamflow Advisory – Vancouver Island, South Coast
ISSUED: 11:00 AM January 11, 2021
The River Forecast Centre is issuing a High Streamflow Advisory for:
• West Vancouver Island, Central Vancouver Island, East Vancouver Island and South Vancouver Island
• South Coast including tributaries around the Sunshine Coast, Howe Sound, Squamish, Pemberton, North Shore Mountains, Metro Vancouver, Fraser Valley and surrounding areas
A series of storms is passing over British Columbia. Following a lull through today the next storm is expected to begin to impact coastal areas later Monday and overnight into Tuesday. This is forecast to bring moderate to heavy rainfall amounts across Vancouver Island and the South Coast. Environment and Climate Change Canada has issued rainfall warnings for areas, with rainfall amounts in the 50-60 mm range anticipated in the Howe Sound and Metro Vancouver areas, and potentially higher over higher terrain and in exposed coastal areas on Vancouver Island. Along with moderate to heavy rain, temperatures are expected to rise, with freezing levels forecast to reach above 2000m. This may contribute additional runoff from rain-on-snow and snowmelt.
River levels are expected to rise in response to this storm, with high flows expected overnight on Monday and through Tuesday. Prolonged wet weather over the past 1-2 weeks has led to ground saturation in some areas, and this may contribute to increased flows in response to this rainfall.
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.
BC River Forecast Centre
Ministry of Forests, Lands, Natural Resource Operations and Rural Development
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.