Weekend weather critical for region

B.C. official says flow in swollen Similkameen River will depend on how much rain falls

Flood watchers have their eyes on the sky as the province enters a crucial period in the freshet season.

“The biggest piece of uncertainty is how much rain do we get over the next 24, 36 hours,” Dave Campbell, the head of the B.C. River Forecast Centre, told reporters on a conference call Thursday afternoon.

Campbell said the Similkameen River, which has triggered evacuation alerts for thousands of properties and caused flooding in Osoyoos Lake, was running around 600 cubic metres per second, with the flow projected to top out at anywhere between 650 and 800 over the weekend “depending on how much rain we get.”

“So obviously a concerning couple of days through the Similkameen, and then as we get into next week we should hopefully see a bit of an easing off.”

Campbell said most low- and mid-elevation snowpack has melted now as a result of record-setting heat this week, but just 10 to 30 per cent of the high-elevation snowpack that feeds major rivers and lakes has become water.

Okanagan Lake today is expected to reach 342.48 metres above sea level — the so-called full pool target — en route to an expected high of 343 metres sometime in early June, according to Shaun Reimer, who manages the system for the B.C. government.

“It’s important to understand I’m not necessarily saying we’re going to reach that 343-metre elevation, but I think it’s very prudent that people who were flooded (and) local governments plan for that in terms of where they want to put their flood-protection measures,” he noted.

The level is currently increasing about five centimetres per day, Reimer said, but the rise is expected to taper off as snowmelt eases.

As of Thursday, the lake was 32 cm lower than where it was at this time last year, but water was flowing in faster than in 2017, when the lake topped out at a record-setting 343.27 m on June 8.

Outflow from the Penticton dam was cut 13 days ago, Reimer added, to avoid damaging equipment downstream, although he hopes to increase it again once the lake inflow starts slowing.

Meanwhile, evacuation orders were issued Thursday for nine homes in Olalla due to rising water in Keremeos Creek, which also prompted evacuation alerts for 62 properties in nearby Cawston.

In Summerland, residents whose properties required sandbagging last year are being urged by the district to do the same this year.

The district also reported little change in the status of Aeneas Creek, along which a local state of emergency was issued in April, but warned that some trees on Peach Orchard Road have been undermined by water and may be dangerous.

And in Penticton, work continues along Okanagan Lake to guard public infrastructure from water and waves using sandbags, armouring and gabion baskets.

The biggest piece of uncertainty is how much rain do we get over the next 24, 36 hours. Dave Campbell