High temps will speed up snowmelt

With summer temperatures forecast for this weekend, it's expected local creeks will swell and there could be flooding.

If cooler overnight temperatures continue in the next few days as forecast, it might delay flooding around local streams, but soaring temperatures forecast for the weekend will begin rapid melting of snow at high elevations.

In fact, Environment Canada meteorologist Doug Lundquist says a ridge of high pressure returns in the next couple of days, with temperatures as high as 28 C forecast for Sunday, and overnight thawing right up to the tops of the mountains.

With 20 per cent more snow than normal accumulated high in the Mission Creek watershed, there’s a lot of snowmelt still to make its way down streams into Okanagan Lake.

Lundquist says he’s expecting more sun and less cloud with this ridge than early in the week, which means temperatures will be higher and there will be more melting.

Because of a hot spell last week and a day of heavy rain the previous week, local creeks are already higher than normal for this time of year.

Dave Campbell, manager of the provincial River Forecast Centre, expects an advisory about Mission Creek will be issued by the weekend.

Low to mid-elevation snow has largely melted in the past couple of weeks, but the cold nights have slowed runoff from higher elevations.

Flows in Mission Creek jumped up Wednesday, but he expected to see a further change when overnight thawing begins at higher elevations.

The seasonal flow into Okanagan Lake was changed by the single day of rain April 26, when a month’s average rainfall occurred in one day, noted Campbell.

However, overall, the snowpack is not that far off normal, with higher-than-normal amounts on the east side of the lake, but lower amounts on the west side, he said.

Kelowna assistant fire chief Lou Wilde said although the melt is a week or so ahead of last year, weather conditions in the next few days should help keep flows down, but higher temperatures next week could cause some problems.

Residents in low-lying areas and near watercourses should take precautions against flood damage, warns Bruce Smith with the Central Okanagan Regional District.

“Those adjacent to creeks and streams in the Central Okanagan should make annual preparations to protect their properties in the event of rapid snow melt combined with significant rain causing rising water levels,” he said.

Sandbags are available from local firehalls, but residents are responsible for sourcing the sand to fill them.

jsteeves@kelownacapnews.com