Melting snows and rising flows

Warm weather over the last several days has brought the Granby and Kettle Rivers up to or higher than normal flows (see figures below). The BC Water Supply Bulletin for April 1 shows the Okanagan-Kettle region at 97% of normal and the West Kootenay region at 118% of normal, indicating an overall normal seasonal flood risk. By the end of April upper elevation snowpack in our region typically switches from accumulation to snow melt. Provincial snow pillows at Mission Creek (north of Big White), Grano Creek (east side of Christian Valley) and Barnes Creek (north of Granby Provincial Park in the Monashees) show upper elevation snow packs near or slightly above average.

Flooding during spring freshet depends on snowpack but is highly sensitive to seasonal weather – as the Water Supply Bulletin notes, heavy precipitation or very warm weather can cause flooding in normal or below-normal snow packs. Above normal temperatures are highly likely for the period between April 19 and 26. The next Water Supply Bulletin will be released on May 8 based on April 1 snowpack data and regional forecasts.

Current (solid) and long-term average (dashed) discharge (cubic metres per second) of the Granby River near Grand Forks.
US Geological Survey graph of the last 60 days of flow (cubic feet per second) at Ferry, WA (bottom, near Midway) and Laurier, WA (top, near Christina Lake)
US Geological Survey graph of the last 60 days of flow (cubic feet per second) at Ferry, WA (bottom, near Midway) and Laurier, WA (top, near Christina Lake)