Dry spring cuts West Kootenay river flooding concerns

·3 min read

The people who monitor the province’s rivers and streams for flood potential say they’re getting less worried about the West Kootenay as the spring progresses.

“On March 1, it was 110% of normal, and I’d say I was concerned about some areas in the southern Interior,” says Jonathan Boyd, a forecaster with the River Forecast Centre. “But by April 1, it was at 100%, or normal, then by May 1 it was 91%.

“Compared to last year, it was 117% in the West Kootenay on May 1,” he told the Valley Voice. “So that’s a 26% difference.”

It’s a far cry from just a year ago at the height of the spring runoff, or freshet, when the high-altitude snowpack was in full melt and a massive thunderstorm hit on May 31. Streams flooded, Kaslo’s water reservoir was badly damaged, the road to Idaho Peak Lookout washed out (and still is), and evacuation orders were issued in several areas.

“It just hasn’t been as wet for the region as a whole,” says Boyd of this year’s weather. “And in the middle of April, we had a high-pressure ridge that resulted in many areas of the province reaching all-time temperature records for those dates. That kick-started the snowmelt in low-elevation sites.

“That will prove a positive in the West Kootenay region, because that got some of that low- to mid-elevation snow out of the way already.”

Of course, any predictions of flooding come with the caution that daily weather is an important wild card. A storm event, timed with the freshet (like last year) can raise the chances of flooding. But right now, that’s not likely.

April continues dry spell

The latest summary of last month’s weather conditions in the West Kootenay reinforce Boyd’s predictions.

The April report by the Southeast Fire Centre shows that drier-than-average conditions were seen for a third consecutive month, with total precipitation just a third of normal (34%). The number of days reporting a measurable amount of precipitation (at least 2 mm) was half of the monthly average, with seven days this month with at least a spit of rain, compared to an average of 14.

“A series of relatively dry Pacific frontal systems brought generally minor amounts of precipitation but frequent elevated winds between the first and the twelfth,” says Jesse Ellis, a fire weather forecaster with the SEFC. “High pressure building upstream of the area dominated for much of the following ten days.”

Dry and unseasonably warm conditions were seen during much of this ten-day period, with the warmest temperature of the month (25.5°C) on April 17. That was followed by a cold front that approached from the northeast the next day, bringing strong gusty winds.

While the mean monthly temperature was just slightly above average (by 0.7°C), two daily temperature records were broken: a 22.9°C day on April 16 broke a high-temperature record for that day, while the -5.3°C morning of April 11 broke the record for that day.

That dry weather has continued into May, and forecasters may soon be starting to talk about drought conditions. While that’s good news for flooding, it’s also just as the wildfire season gets into full swing.

John Boivin, Local Journalism Initiative Reporter, Valley Voice

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