Heavy snowfall in the Okanagan and Similkameen river basins in British Columbia has improved the water supply picture in those areas, but not by much, the province reports.
In its snowpack and water supply bulletin Monday, the government said snow conditions in those two river basins are still below normal and are expected to have “diminished” runoff this spring and “potential water supply challenges” come summer.
The Peace River basin, meanwhile, has above normal snowpacks and is likely to experience above-normal spring runoff as the snow melts, the province said. That could translate to flood risk in areas such as the tributaries and inflows to the Williston Reservoir — not the Peace River below Williston Reservoir — due to higher-than-normal runoff.
Generally, most other areas of the province have near-normal snowpacks, which mean near-normal spring runoff for most river basins and low likelihood of flooding on major rivers such as the Fraser, Nechako, Thompson, Skeena and Nass, the province said.
That said, extended periods of hot weather and/or heavy rain from any frontal or convective storm systems during early May to mid-June could lead to flooding on smaller rivers and streams in the B.C. interior, the province added.
River basins in areas that have seen “significant” mountain pine beetle infestation, such as the Nechako and Mid-Fraser, have potential for higher-than-normal river and lake levels, the province said.
“Flooding on Vancouver Island and other coastal drainages, such as the rivers draining out of the South Coast mountains, is unlikely as they normally experience their high flows during fall and winter rain storms, not from spring snowmelt,” the province noted.
However, the bulletin noted, flooding is possible around those drainages if “intense and prolonged” rain occurs during snowmelt.