Tuesday, December 27, 2011

No White Christmas For Canadians

The past two winters in Canada have been somewhat odd.  Last winter we had a pretty ordinary winter while south of us the US got blasted in a way that one has to go far back in the record books to find comparables.  It was almost as if we were on different continents.  This year, as this article makes clear we have had no snow across the country.

What I find curious here is that this means that a not so low probability event in Vancouver has been repeated in the Prairies and in Ontario and Quebec and the Maritimes and even Newfoundland.  If we were to assign a probability of one four to each of them save BC at say ¾, all of which is super conservative but overcomes any geographic linkage and dependency, then the probability of this happening is around once per millennium.  Obviously some factor is making it more likely than it appears.

In the meantime, the US is having a pretty ordinary winter and perhaps a repeat of some recent past decent winters.

Another thing to think about regarding Canadian cities.  Their internal density has been steadily increasing and this has increased the heat island effect of the cities themselves.  If heat output is measured on a per capita basis, then the rising population in the cities is also combined with greater heat output as few now do without sufficient warm living space or all the add-ons.

No white Christmas for Canadians in 2011

by Staff Writers

Ottawa (AFP) Dec 21, 2011

Most Canadians will not wake up to a white Christmas on December 25 for the first time since Canada's weather office began recording snowfalls in 1955, the government agency said Wednesday.

With just days before the Christian holiday, Environment Canada senior climatologist Dave Phillips told AFP he has never seen so little snowpack in Canada's cities.

And the forecast for the coming days is sunny and very mild.

"A white Christmas is usually a sure thing in Canada, but not this year," Phillips said.

"We are usually the snowiest country in the world," he said. "But this year, like no other since we've been monitoring in 56 years, there will be many Canadians just dreaming of a white Christmas and not getting one."

For a city to qualify as having a white Christmas, Environment Canada must note at least two centimeters (0.79 inches) of snow on the ground at 7 am on December 25.

This month has been on average six to seven degrees (Celsius) warmer than normal and most snow that has fallen has melted soon after hitting the ground.

Gander, Newfoundland -- usually "the snowiest place in Canada" -- only has a trace of snow on the ground today, Phillips noted.

Winnipeg, Manitoba -- once ranked the coldest metropolis on Earth -- usually has a 98 percent chance of snow at Christmas. But temperatures in the west of the country are expected to hover just above freezing in the coming days.

Other cities in the east like Saint John's, Newfoundland have a few centimeters of snow on the ground but rain is forecast.

Phillips said Canadian winters are generally becoming milder, and starting later, and so the idea of a white Christmas may be something of the past.

He pointed to a combination of climate change and an "urban heat island effect" created by Canada's growing cities. High energy use generates heat that is retained by materials in urban developments, resulting in areas that are consistently hotter than surrounding rural areas.

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