Hot days speed up rise in lake level
Okanagan Lake hits level of 1990 flooding; officials say many properties remain at risk due to inadequate protection
A heat wave followed by thunderstorms could accelerate the flood risk along Kelowna creeks and Okanagan Lake, officials say.
Temperatures are expected to reach 29 C today, seven degrees warmer than usual, followed by rapid cooling Wednesday, when the high temperature is expected to reach only 14 C.
The combination of conditions could quicken the snowmelt and hasten the flow of water in Mill Creek and Mission Creek, and also accelerate the rise of the lake.
“A ridge of high pressure over the southern Interior of British Columbia will remain in place Tuesday, leading to unseasonably warm weather,” reads part of a special weather statement issued Monday by Environment Canada.
“This warm spell will accelerate snowmelt leading to rising rivers, possibly causing concerns related to flooding,” the statement said.
Strong winds and thunderstorms are expected Wednesday from a short-lived cold front, before temperatures rebound to the high 20s for the rest of the week.
Okanagan Lake was measured at 342.87 metres above sea level on Monday afternoon — the level of 1990’s flood — and 13 centimetres below this spring’s projected maximum level of 343 metres above sea level.
“Our wharf is now under water,” Bob Would, a waterfront resident on Casa Loma Road in West Kelowna, said Monday.
The edge of the lake, however, is still about 60 centimetres below his property’s retaining wall, which has nevertheless been augmented by two layers of sandbags.
“I’m not too worried about flooding on our property,” Would said.
But authorities who’ve conducted a shoreline inspection of waterfront properties say many other owners still haven’t taken the necessary flood precautions.
“Officials observed that many at-risk properties lack adequate foreshore protection to (the projected flood level of 343.6 metres above sea level,” a mark that includes a buffer for wave action, Central Okanagan Emergency Operations stated in a release.
Water levels are expected to remain extremely high into July.
Local authorities appealed for boaters to stay off the lake during the long weekend, citing concerns about erosion caused by wakes. Many appeared to take heed of the warning, Would said.
“There were boats out there, but not as many as on previous May long weekends,” Would said. “And we didn’t see anyone being idiotic, travelling really fast along the shore. I think most people want to be considerate.”
Flows in Mission Creek, which carries one-third of all water that enters Okanagan Lake, were about 45 cubic metres per second on Monday, still less than half the rate that caused flooding on May 6.
An evacuation order continues for two properties along Marchbank Road in the North Westside area of the regional district. Officials say it will be rescinded when mitigation efforts are in place and it is again safe. Three residents from one property are affected and the second property was not occupied.