Worst of flood threat over for small, medium bodies of water
Reimer suggests lake might still rise but will decrease when peaks sometime early June
Okanagan Lake’s rise is slowing, the Similkameen River’s flow is falling and B.C.’s flood threat is dwindling, provincial officials said Tuesday as the latest snowpack bulletin was released.
The new data, current as of May 15, pegged the Okanagan basin snowpack at 126 per cent of normal, down from 206 on May 1, and the Similkameen basin at 56 per cent of normal, down from 201 just two weeks ago.
As a result, “The risks that we see through the Boundary and Similkameen and Okanagan are really declining now from snowmelt alone,” said Dave Campbell, head of the B.C. River Forecast Centre.
He attributed the rapid melt to the “extreme” temperatures over the past month that averaged about 5 C above normal.
Campbell suggested the worst of the flood threat is over for small- and medium-sized water bodies, meaning all eyes will now be on major systems, such as Okanagan and Shuswap lakes, and the Thompson and Fraser rivers, for the next one to three weeks.
With the much-reduced snowpack in the Similkameen, the threat of that river again rising out of control has been cut.
“The risks related to snowmelt alone are diminishing, and so really we’re shifting that risk over to the rainfall side of things at this point,” said Campbell, noting there’s “nothing on the short term (weather forecast) we’re worried about.”
As for Okanagan Lake, it was swishing around at 342.60 metres above sea level as of noon Tuesday, up just two centimetres over the previous 24 hours.
Shaun Reimer, who manages the Okanagan Lake system on behalf of the B.C. government, said that gain marks a stunning slowdown from several weeks ago, when the lake was adding as much as seven centimetres overnight.
“That seems to be a continued trend is that the rate of rise in the lake is slowing, and that’s very positive, in that it’s indicative that the tributaries that are feeding Okanagan Lake are dropping,” said Reimer.
Inflow from tributaries to the Okanagan River south of Penticton “has also fallen off,” he continued, “and this has allowed us to increase our outflows through the Okanagan Lake dam.”
Reimer said he’s still warning local governments to prepare for the lake to reach 343 m, “but I don’t think, based on the current conditions, we’re going to get there.”
While he didn’t speculate as to where it might top out, “I do think the lake will continue to rise over the next 10 to 14 days, but, again, that rate of rise will decrease over that time until the lake peaks sometime in early June.”
Chris Duffy, the executive director of Emergency Management B.C., said there were approximately 700 properties across the province under evacuation orders as of Tuesday afternoon, down from several thousand last week.
Those properties still evacuated include dozens around Osoyoos Lake and Keremeos.
Meanwhile, the Regional District of Okanagan-Similkameen on Tuesday rescinded evacuation alerts for 131 properties in Area C north of Oliver and 54 properties in Okanagan Falls.