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High snowpack, low water levels in Okanagan Lake

Lake levels reflect snowpack

Dale Cory

The latest snowpack numbers may not ring alarm bells, however, with temperatures on the rise, there is cause for concern.

The snowpack in the Okanagan is still at 116 per cent of normal, and that is forcing water managers to lower Okanagan Lake levels in preparation for the spring run-off.

“We’ve been coming down a half centimetre per day, or 15 cm. per month. So, about a foot in the last two months. What you’re seeing on Okanagan Lake is a lot of sand bars develop. That’s because of that draw down,” said Okanagan section head and Penticton dam manager Shaun Reimer.

"It’s been drier the last few weeks, and I think we’re downgrading some of our inflow forecasts coming into Okanagan Lake compared to where we were three weeks to a month ago. As for Okanagan Lake, because we've been expecting this elevated runoff, we’ve been drawing it down fairly aggressively. Our outflows for the last month-plus have been certainly higher than they normally are for this time of year.”

The Okanagan has experienced a significant divide, with east side stations reporting anywhere from 125 to 180 percent of normal, while west side values range from 80 percent of normal to around 105 percent.

“Because we’ve been drawing down the lake, our models are showing that it should still be management with us only getting up to the full pool elevation target that we try to get to on an annual basis. That being said, if conditions change or it gets very wet, or we have a later build up of snow, or the snow melts and comes down so quickly that it overtakes our ability to get the water out, then again the lake can rise up higher than we’d like. That’s always a possibility.”

While Okanagan Lake may not be at risk, some of the creeks along the eastern side — most notably, Mission Creek — has the possibility of localized flooding, especially if the Okanagan receives a sudden warm spell for five to 10 days, followed by heavy rain.

The spring runoff during 2018 caused a great deal of damage in Osoyoos, where residents were critical that a lowered Okanagan Lake resulted in a higher than normal Osoyoos Lake  — and resulted in localized flooding.

“A few years ago, when we had the issues on Osoyoos Lake, they were primarily due to the high flows of the Similkameen. Right now the snowpack in the Similkameen is fairly average,” added Reimer. “We hope the snow comes down in a measured way, and there won’t be those high flows that backwater into Osoyoos Lake and bring it up so substantially.”

The best case scenario is for temperatures in the mid teens during the day, cooler evenings, and no precipitation.



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