Weather: The winter when snow became a bad, four-letter word

Saturday, May 10, 2008

For parts of southern Ontario, the winter of 2008 brought the second-highest snowfalls on record, causing burnout to road and highway crews. And, paradoxically, it may just be another product of global warming

by HENRY HENGEVELD

When I tell my grandchildren about the bad snow years of the 1950s - the years when they needed bulldozers to push the snow banks into the fields because the plows couldn't get through anymore - they sort of smile at me. They think I'm pulling their leg.

Maybe this winter will help them believe my tales. In fact, now they can spin their own stories for their grandchildren - about the winter of 2008!

This winter's snowfall may, in fact, become the granddaddy of them all - at least in central and eastern Ontario. By March 9, snow amounts recorded at Pearson International Airport since November had already reached 190 centimetres. That already ranks this season as the second highest total seasonal snowfall on record, with weeks of potential snow fall yet to come. The record year of 207.8 centimetres was in 1938-39.

A new record for February snowfall has already been set. The 76.8 centimetres that fell during this February was about 10 centimetres more than the previous record, set in 1950 (although this February did have an extra day). During December to February, at least a trace of snow fell on 60 of the 91 days!

It's a similar story for regions across much of southern and eastern Ontario. Ottawa has also already achieved the second highest seasonal snow fall on record - 411 centimetres. Trenton has so far recorded 257 centimetres and Windsor's is up to 169.

All that snow has appeal - plenty of winter recreation, landscapes of fresh fallen snow, with tree boughs weighted down with the stuff and fences and lamp posts piled high. Most people I met were surprisingly upbeat about this much snow, even cheering for more to set a new seasonal record.

However, the reality of working in a deep snow cover environment is something else. One of my sons plows snow for his winter living in the Trenton area. He has always maintained that plowing snow is fun - until this winter. He has had to be out virtually every day during the past two months, either to plow or salt. It became very wearisome.

Road and highway crews across the region have also been complaining about burnout as they tried to keep most of the motorways passable.

For the first time in more than a decade, a massive snow removal plan had to be implemented in Toronto, at a cost that has already exceeded $40 million. Thank goodness, this time the mayor didn't embarrass us all by calling out the army! A lot of other outdoor work is simply being postponed. For such people, snow has become a bad four-letter word.

Of course, there was more to this winter's weather than snow. With all those snowy days comes a lack of sunshine. There was also the very warm period in early January, when temperatures jumped into the mid-teens throughout much of southern Ontario for three consecutive days.

This helped push average December to February temperatures for the Great Lakes region to well above normal - by about 1.5°C. It also helped melt some of the snow already on the ground from the December storms, thus making room for some of the subsequent snow falls.

Then there were the strong wind events, particularly at the end of January. On Jan. 30, winds accompanying an intense cold front passing through reached strengths in some locations of up to 126 km/hour. They caused numerous downed trees and power lines, and local whiteout conditions due to lake-effect snow.

Because they remained intense for an extended period of time, they also help push waters from the west ends of the lower Great Lakes to their east ends. For a short period of time during the storm, the difference between water levels recorded at Buffalo and Toledo was more than 4.7 metres. At Goderich and Parry Sound, on the east shores of Lake Huron, water levels rose approximately 0.4 and 0.6 metres, respectively, for a short period of time. On Lake Ontario, levels at Kingston increased by 0.5 metres as levels at Burlington dropped roughly 0.4 metres.

The rest of Canada had its share of winter weather, although a bit less dramatic. On average, the country was slightly warmer than normal (0.5°C), with near normal precipitation amounts.

There were, as usual, regional abnormalities. Northern regions of the Yukon and Northwest Territories were much warmer, while eastern Nunavut was quite cold. The southern parts of the country - other than southern Ontario - were also relatively dry, while the high Arctic and the Hudson Bay region were quite wet.

A number of people have asked me jokingly whether we can also blame this snowy Ontario winter on "global warming." They tend to raise their eyebrows rather skeptically when I tell them, "Possibly!" They seem to be unaware, or forget, that climate modellers have warned for decades that warmer climates will cause weather fronts and related storm tracks that move across the continent in mid-winter to drift further north. This brings more moist air masses from tropical regions northward into our region.

While the total number of winter storms will likely decrease, the number of very intense storms may rise. Hence, they note, Ontarians can expect, on average, to progressively get shorter but more intense snow seasons as the climate warms.

On the other hand, last year was the second lowest on record for snow accumulation. So is it warmer climates, or just climate variability? After all, it's also a La Nina winter. It may, in fact, be a combination of the two! BF

Henry Hengeveld is Emeritus Associate, Science Assessment and Integration Branch/ACSD/MSC, Environment Canada