The BC River Forecast Centre is issuing a High Streamflow Advisory for Central Vancouver Island, including streams and rivers in the Port Alberni and surrounding areas.
A strong Pacific storm is expected to spread heavy rain across Vancouver Island and south-west BC on Wednesday evening and through the day on Friday. Total rainfall amounts of 90-120 mm, and potentially more over higher terrain, are currently forecasted from Tuesday evening to Thursday morning. Temperatures are expected to remain high throughout this event, with freezing levels generally above local mountain top level. In addition to heavy rainfall, melt of snow in low elevation areas is also expected, and it will contribute to streamflow runoff. At high elevations, deeper snow will be able to absorb much of the rain and energy from the warm temperatures.
High streamflow is expected throughout the region on Wednesday, and potentially into Thursday morning. At this point, forecasts are not indicating the potential for rivers to reach flood stage, however low-lying areas may experience minor flooding. With snow at low elevations, minor flooding is also possible in areas with poor drainage or where drainage is impeded by snow.
The public is cautioned to stay clear of rivers and riversides during the high streamflow period because the quickly flowing water and the adjacent riverbanks are potentially unsafe.
The River Forecast Centre will continue to monitor weather and streamflow and will provide updates 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.