Four downsides of our weirdly warm winter

Take the rather large example of the Great Lakes. “What happens right now in the lakes has consequences throughout the whole year,” says Sapna Sharma, a professor of biology at York University.

There was a brief blast of Arctic air earlier this month, but Wednesday had exceptionally weird weather even in an exceptionally weird winter.

By noon, Toronto had already cracked the record for the warmest Feb. 15 ever by a full degree. The mercury at Pearson airport registered 13.2 degrees Celsius at midday, according to Environment Canada, beating the previous record of 12.2 set in 1954. And it came on the heels of the hottest Valentine’s Day ever in Toronto, which topped out at 9.2 C.

“Breaking back-to-back daytime highs in the middle of February is pretty noteworthy, and pretty rare,” says Geoff Coulson, a meteorologist with Environment Canada, suggesting these temperatures would be normal for late April.

“And it’s been part and parcel of a generally milder than normal winter, not just in Toronto, but across many areas in the province.”

Coulson said that in the coming months, researchers at Environment Canada will be analyzing factors like ocean currents to determine the role climate change played in this extreme winter. One warm day is not that unusual, and a warm month happens from time to time, but this winter every month has seen significantly warmer-than-average temperatures.

December, January, and February so far were all between 1.6 and 2.8 degrees warmer than the long-term average, and Coulson says the trend is forecasted to continue until March.

Here are some of the ways this warm winter has disrupted our typically icebound region.

The Rideau Canal conundrum

Ottawa’s famous skateway, the world’s longest skating rink and a UNESCO World Heritage Site, has opened to the public every year since 1970-71. But the Rideau Canal hasn’t yet opened for skaters at all this year, and the National Capital Commission, which manages the rink, issued a safety advisory earlier this month warning the public to stay off — the ice remains dangerously thin. The commission has not said when it will determine the skateway simply won’t be open at all for the first winter in its history.

The NCC says that to safely support skaters the ice needs to be at least 30 centimetres thick, which requires ten to 14 consecutive days of temperatures between -10 and -20 C. Ottawa had a record high on Wednesday of 8.3 C, with more warmth ahead.

“We remain hopeful that we’ll be able to welcome skaters to the Skateway this year,” spokesperson Valerie Dufour told the Star.

NCC data shows that the average length of each skating season has shrunk since the 1970s, and the commission partnered with Carleton University last year to address the impacts of climate change on the skateway.

Shinny? What shinny?

RinkWatch is a citizen-science initiative led by researchers at Wilfrid Laurier that analyzes user-submitted backyard ice-rink data to monitor winter weather and study the impacts of climate change.

According to Robert McLeman, a professor in the Geography and Environmental Studies department who runs the program, “this is shaping up to be the worst winter” for backyard rinks in southern Ontario since the initiative began tracking data ten years ago.

While end-of-season data is not yet available, McLeman says, across North America outdoor rinks have seen later opening dates and fewer skating days this winter than in recent years, and many rink makers in the Northeastern U.S. have already given up trying to maintain their surfaces.

“Although it is an especially mild winter, it’s consistent with trends we have observed using historical weather data: the number of days cold enough to build and maintain an outdoor rink has been declining since the 1940s across eastern North America, with Toronto and the lower Great Lakes region being particularly affected,” McLeman said by email.

Great Lakes, lacklustre ice

Ironically, one of the symptoms of less ice is more snow — at least in some areas.

“Lake effect snow” happens when cold air moves across open water on the Great Lakes, picking up warmth and moisture along the way, which falls as snow when the system hits land. Long the bane of Buffalo, this phenomenon played a part in the massive December blizzard in western New York state.

Normally, lake effect snow is an early-winter phenomenon — but maybe not this winter.

The Great Lakes have far more open water right now than is historically normal, according to Sharma, who specializes in the impacts of climate change on lakes. While the average ice cover for Lake Ontario is 20 per cent, it’s currently at two per cent, Sharma says. For the Great Lakes as a whole, the average is 42 per cent; as of Tuesday the current number is seven.

Normally, as ice cover grows, it limits the brunt of lake effect snow as the winter wears on. But without that ice “lid” on the lakes, the potential for massive snow dumps remains.

Beyond the winter

Mike McKay, executive director of the Great Lakes Institute for Environmental Research at the University of Windsor, spent Tuesday aboard a Coast Guard vessel on Lake Erie, taking samples to better understand the lake ecosystem — ironically, aboard an icebreaker.

Among other things, McKay studies harmful algal blooms, colonies of algae that grow out of control and can produce toxic compounds. Such blooms in Lake Erie led to drinking-water advisories in Toledo, Ohio in the summer of 2014.

Winter is “a black box in our understanding of the ecosystem,” McKay says, which is why he was out studying lake samples this week. Usually, the lake ice “lid” prevents wind from churning algae-promoting nutrients up to the surface, instead letting them to fall to the bottom and be trapped by sediment.

Two of the last three winters that had little Great Lakes ice, McKay said, also had dry springs, preventing even more nutrients from running into the water and potentially dampening the effects of the ice shortfall. McKay wonders what a “perfect storm” of a rainy spring and ice-free winter would mean for harmful algal blooms.