Melt-cycle: snowpack pedals downward as drought comes up closer in rear view mirror
If you thought you were having a bad day, think again.
The West Kootenay regional snowpack remains extremely low as May moves on, clocking in at a paltry 66 per cent of normal.
According to the Snow Survey and Water Supply Bulletin — produced by the B.C. Rivers Forecast Centre — the entire province is on the drier side of the ledger when it comes to the remaining snowpack lodged in B.C. watersheds (57 per cent on average).
In the West Kootenay, the snowpack has dropped down from 70 per cent last month. Only the South and North Thompson (74 and 67 per cent, respectively) regions, as well as the Boundary (74 per cent), sat with a higher percentage snowpack index than the West Kootenay out of 27 recorded basins.
As of May 15, the provincial snowpack is extremely low, averaging 57 per cent of normal across B.C. Last year, the provincial average was 91 per cent.
“So far, 31 per cent of peak snowpack has melted this year, driven by low elevation melt in April and the significant heat event on May 9-12,” noted the report. “Last year, temperatures were much warmer and 43 per cent of the snowpack melted by this time.”
On average, 17 per cent of the seasonal snowpack melts by May 15.
A below normal spring freshet flood hazard is expected to continue this season for most of the West Kootenay and Boundary region due to the low snowpack, but local flooding from extreme rainfall over the next six weeks is still a possibility.
“Low snowpack and seasonal runoff forecasts combined with warm seasonal weather forecasts and lingering impacts from on-going drought are creating significantly elevated drought hazards for this upcoming spring and summer,” the report explained.
Rain and snow
In general, precipitation was below normal in May for the Kootenay region as well as most of the province.
The onset of the snowmelt season has been mixed across the province. In low-to-mid elevations, particularly in plateau terrain in the B.C. Interior, early melt of a shallow snowpack has occurred and many of these areas are now snow-free.
“Higher elevation mountain snowpack has experienced a delay in melt due to cooler temperatures in late April, and some areas experienced additional late-season snow accumulation during recent unsettled weather periods,” the report explained.
Chance of weather
An El Niño advisory is still in effect, according to the Climate Prediction Center at the U.S. National Weather Service.
El Niño is the warm phase of the El Niño-Southern Oscillation (ENSO), meaning conditions trend toward warmer winters across B.C., with below normal snowpacks and earlier snowmelt.
The CPC forecasts a likely transition to ENSO-neutral conditions over the April to June 2024 period (85 per cent chance).
“A La Niña Watch remains in effect from the CPC, with increasing odds of La Niña conditions developing in June-August (60 per cent chance) and likely continuing and impacting B.C. into fall-winter 2024-25 (next year),” noted the report. “La Niña winters are often relatively cool and wet, potentially causing delayed snowmelt if cooler temperatures persist.”
Seasonal weather forecasts from Environment and Climate Change Canada (ECCC) continue to indicate a moderate likelihood (40-95 per cent chance) of above normal temperatures across all of B.C. over the May to July period.
Current projections for May to July suggest above normal precipitation in portions of the southern Interior and Kootenay.
Timothy Schafer, Local Journalism Initiative Reporter, The Nelson Daily
