Rainfall and warmer temperatures ahead continue to be worries, but the level of Osoyoos Lake has changed little in the last 24 hours.
As of 5:30 p.m. Friday, Osoyoos Lake was at 916.32 feet above sea level. That’s an increase of about a third of an inch since the same time Thursday.
Discharge on the Similkameen River, which is normally a predictor of changes in the lake’s level, has actually fallen slightly, to 27,000 cubic feet per second (cfs) as of 5:30 p.m. Friday from 29,000 cfs a day earlier.
The lake is currently just over an inch and a half below its high mark of 916.45 reached last Saturday.
Meanwhile, cooler temperatures should continue through the weekend, with a chance of showers on Saturday, but Environment Canada forecasts temperatures to climb back up into the 30-degree range by the middle of next week.
While rain and higher temperatures can exacerbate the flood risk, it’s also true that snowpacks throughout the province have been greatly reduced by the past week’s warmer weather and snowmelt.
Dave Campbell, head of the B.C. River Forecast Centre, told media on a conference call Thursday that in most areas of the province snowpack has dropped to below normal for this time of year.
However, it still remains above normal in areas of the province, including the Okanagan and other parts of the Southern Interior, where snowpacks have been extreme.
That information is based on a preliminary analysis of May 15 snowpack data, which will be released early next week.
Campbell said there is very little snow at low elevations currently. About half the snow has melted from mid-elevations and about 10 to 30 per cent has melted at upper elevations.
This means that smaller river systems will probably see another week or so of elevated risk from snowmelt, while larger river systems are probably looking at one to two more weeks, Campbell said.
Larger lakes could see flood risk until later in May or early June, he added.
“As we enter into the long weekend, obviously the flows are expected to be very high across all the rivers in the province with the hot weather,” said Campbell. “I would urge the public to exercise extreme caution near any waterway. The banks can be unstable and water swift and it poses a significant public safety issue, particularly as people might be going out into the back country on the weekend.”
Campbell said he urged people not to drive through floodwaters on highways or roadways because of hidden hazards. He also recommended people check with DriveBC and EmergencyInfoBC.
Shaun Reimer, the B.C. official who oversees Okanagan dams on the Canadian side, including the dam at Okanagan Lake in Penticton, said levels of Okanagan Lake are rising due to snowmelt.
“The water is coming into Okanagan Lake even faster than it did last year, even though we are 32 centimetres below where we were for the same date for last year,” Reimer said.
The lake is expected to reach full pool by this weekend, and Reimer advised authorities to prepare flood protection measures in anticipation that Okanagan Lake could reach 343 metres above sea level, which is around a half metre higher than full pool.
Reimer said he’s been receiving calls from people concerned that about 12 days ago, outflows from Okanagan Lake were reduced. This, he said was necessary to protect infrastructure and communities downriver.
By holding this water back, he said, it’s raised the height of Okanagan Lake by six centimetres, which he said should be viewed in the context of a lake that’s rising at a rate of five to six centimetres a day.
RICHARD McGUIRE
Osoyoos Times
