Original Published 10:42 May 19, 2022
By John Boivin, Local Journalism Initiative Reporter
Last month was the coldest April in more than a half century of record keeping in the West Kootenay, says a weather forecaster with the Southeast Fire Centre.
“We’ve been in this kind of recurring northwesterly flow pattern for the last few months,” said fire weather forecaster Jesse Ellis, who compiles monthly weather records from the Castlegar SEFC headquarters. “It’s related to the fact we’re in a continued La Nina phase of the El Nino Southern Oscillation, or ENSO.”
The average overall mean temperature was 5.8°C, a full three degrees below average.
While two daily low-temperature records were set (on the 13th and 14th), the coldest day, -6°C on the 13th, was still below the record set in 1979, when the mercury dropped to -7.5°C.
The dry spell also continued in April. Total monthly precipitation was below normal for the third month in a row, this time by almost 40%.
“We haven’t figured out the impact these large-scale, global weather patterns have on precipitation,” says Ellis. “So the fact we’ve had three months in a row makes me think there’s something there, in terms of a driving force, but we don’t know what that is.”
The simplest explanation, says Ellis, is that cool air holds less moisture than warm, so the cooler temperatures may be responsible for the reduced rain and snow.
“In a northwesterly flow, you may need 50% more storms to come through to get the same amount of moisture as in a milder southwesterly flow,” he says.
Ellis says the region should see a return to seasonal temperatures by mid-May.
This item reprinted with permission from Valley Voice, New Denver, British Columbia