The depth of the snow pack in the Kootenay and Columbia regions remains above normal, leading to some concern by the provincial spring runoff prognosticator that a threat of flooding is still ahead.
The Snow Survey and Water Supply Bulletin from the River Forecast Centre (RFC) revealed the two regions possessed the fifth and sixth highest snow packs in the province out of a total of 14 areas.
Sitting at 127 per cent and 125 per cent, respectively, of the normal snow pack as of April 1, the Kootenay and Columbia basins are poised to let their hair down soon with hotter weather settling into the region.
The April 1 snow survey is considered to be the key survey of the year for assessing the impact of snow pack on the seasonal water supply and for gauging flood risk.
The snow pack plays an important role in seasonal flood risk by providing water for melt and runoff.
“In years with elevated snow packs there is an increased likelihood of flooding,” the report stated. “This year, snow packs are at levels of concern for increased flood risk in the … Columbia, Kootenay … basins,” the report read.
But the prospect of flooding depends on weather conditions, and cannot be forecast as a result of snow pack levels alone. The greatest risk of flooding comes from above normal snow packs combined with well above normal temperatures and heavy rainfall, a scenario that places like Fruitvale (Beaver Creek) and Trail Creek in the Silver City could experience later this month.
Very wet conditions were recorded in the area, creating more snow at higher elevations and lending itself to the fifth highest April 1 snow pack observed since 1953, and similar to levels observed in 2007.
A long-range weather forecast by the RFC suggested two conditions that may worsen the flood risk in the region, including a forecast for cooler weather to the end of May. This will prolong the snow accumulation season and add to the snow pack at the higher altitudes.
This cool weather will be followed by warmer than normal temperatures into late spring and summer, creating a rapid transition from cooler to hotter weather and releasing the extra snow melt water.
By April 1 about 95 per cent of the annual regional snow pack has accumulated. The transition from snow accumulation to snow melt generally occurs in the middle of April.
Snow melt-driven rivers in the region generally reach their peak levels in May and June.
La Niña conditions across the Pacific region have been weakening and it was predicted the La Niña event would break last month, even though atmospheric patterns show it is still active.