Large ice floes on south side of William R. Bennett Bridge

Ice floes on Okanagan Lake

It was an unusual sight for some during their morning commute from West Kelowna Thursday morning.

Large but thin ice floes on Okanagan Lake appeared on the south side of the William R. Bennett Bridge.

The very thin sheets of ice covered a large area of the lake, forming from the middle of the lake toward, but not reaching, each shore.

It is interesting ice floes are forming now as opposed to late fall and winter when temperatures plummeted to -15C to -20C for extended periods of time.

So while it's not clear the precise reason, Dr. Robert Young, associate professor of Earth, Environmental and Geographical Sciences at UBC Okanagan, does have a theory.

"First of all," he says, "the air is extremely calm so the cooling is going to be at its maximum."

"With clear skies the heat is not being replenished because of wind driven currents below the surface. So, you will get conditions approaching freezing on different parts of the lake."

Young says the sunshine we have been experiencing many afternoons can penetrate the lake bed along the shoreline preventing the shallower portions of the lake from freezing.

He says it has been colder than normal with temperatures falling to as low as -11C on some nights the last little while.

Similar conditions were prevalent last week when Carleen Cook came upon chunks of ice which had broken away and drifted onto a beach in Casa Loma.

It's not unheard of for Okanagan Lake to freeze over, although it's been 55 years since it last froze over in December of 1968.

In fact, dating back to 1893, there have been nine recorded instances of the lake freezing over.

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