High streamflow advisories issued for West Kootenay-Boundary rivers
The waters of several West Kootenay-Boundary rivers are rising to such an extent the province’s flood water watchdog has issued advisories.
The BC River Forecast Centre said Tuesday a high streamflow advisory is now in place for the Salmo River near Salmo, the Moyie River near Yahk — down from a flood watch on Monday — and the Granby River near Grand Forks.
Rain on Monday and Tuesday has raised water levels significantly, the centre reported, with around 10 millimetres falling in most areas. In addition, with temperatures remaining low while the rain fell, some precipitation fell as snow at higher elevations.
A high stream flow advisory means that river levels are rising or expected to rise rapidly, but that no major flooding is expected, but minor flooding in low-lying areas is possible.
High stream flows are expected on small to medium sized watersheds throughout the West Kootenay-Boundary region.
“The Moyie River is expected to reach a two‐year flow level and flows may exceed bank full levels,” the report predicted.
Flows on the Salmo River are expected to remain below the two‐year flow level.
The snow pack throughout the region is elevated due to accumulation through April, meaning a delay in the onset of spring melt. May 1 snow pack was 142 per cent of normal through the Kootenay region.
River levels have risen through the past week with warmer weather and snowmelt throughout the region. Snowmelt at the Moyie Mountain snow pillow has been approximately 20‐25 mm. per day over the past few days.
But that does not mean the worst is over. Snow is still abundant at higher elevations, the Forecast Centre reported, and “ongoing melt will continue to feed runoff to rivers in the region.”
A high-pressure system is forecast to move through British Columbia over the next few days and Environment Canada is forecasting warmer temperatures through the region, meaning river levels in the West Kootenay are expected to recede over the next day or so.
However, warm weather Wednesday and Thursday will increase snowmelt, pushing river levels up throughout the region later in the week.
- The Salmo River near Salmo peaked on Monday at 202 m3/s, below the two‐year flow level of 246 m3/s.
- The Granby River near Grand Forks rose through Monday and into Tuesday, and is currently leveling off. Current flows are at 229 m3/s, slightly under the two‐year flow level.
- The Moyie River at Eastport is currently flowing at 128 m3/s and is leveling off. This is currently below the two‐year flow level of 149 m3/s.