Why night-time heat can be deadly

It’s not just daytime heat in the summer that can be deadly — a rising trend in night-time temperatures is also raising health concerns.

Over the past five decades, the average minimum temperature in July has gone up from 13.7 C to 16.4 C, according to Environment Canada.

Those figures don’t appear deadly on the surface. But they show a dramatic trend that the night-time temperatures in Toronto are definitely getting warmer during the summer, says Dave Phillips, senior climatologist with Environment Canada.

 “There is more and more evidence that climate change is about night-time warming rather than day-to-day heat,” said Phillips.

And that may bring big trouble. If you overheat and have no way of cooling down you can suffer from heat exhaustion. In more severe cases, it can lead to heat stroke, which if not treated immediately, can be fatal.

Usually, the body is able to cool down through evaporation of sweat on the skin. But in cases of extreme heat or high humidity the body can’t do this.

The phenomenon of higher evening temperatures most likely occurs because “heat absorbed throughout the day by dark structures and surfaces in the city is released overnight, preventing the city from cooling off,” according to a recent Toronto Public Health report.

 “Having the opportunity to cool off, even for a few hours, is critical in preventing heat-related illness and death.”

The report, presented to the Toronto Board of Health earlier this week, adds that “the daily minimum temperatures are increasing faster than the average or maximum temperatures.”

That trend is something Toronto Public Health is concerned about. “Higher night temperatures can have an effect on the ability to cope with the heat,” said Elaine Pacheco, a manager with Toronto Public Health.

 “In the evening, if temperatures cool down significantly, especially in an extended heat wave, people have an opportunity to get relief from the day time high,” she said.

In Europe in 2005 and Chicago in 1995 hundreds of people died during heat waves. The problem then was the night time temperatures didn’t fall, said Phillips. Even those in good health succumbed to the high temperatures. There simply wasn’t any relief.

There will be more of the same in the years to come says Phillips. In fact, the difference between daytime highs and night-time lows in the summer is slowly shrinking.

In addition, the dew point – a measurement of humidity – is increasingly elevated at night, which means your body is not able to perform as its engineered to do – get rid of natural heat and cool off, said Phillips.

Some nights earlier this summer the dew point was 23 C or 24 C during the day and even when the temperature dipped to 25 or 14, the dew point remained the same. “That’s unbelievable,” said Phillips.

“It’s like being in Savannah, Georgia rather than Phoenix, Arizona.”

Traditionally, the difference between a daytime high and night-time low in Toronto was quite wide with a high of about 28 C and a low of 15 or 16 C.

But during the latest heat wave, the daytime high reached about 35 C and the night time low only dipped to 25 C. That just doesn’t offer any relief — especially for people who don’t have air conditioning.

Phillips ran some data for the Star to illustrate the shrinking range. The difference in the 1960s was about 12.7 degrees; in 2000, it was 10.6 degrees. “This is clearly how the thermal climate in Toronto in the summer is changing.”

According to the Environment Canada data from Pearson Airport, in the 1960s there were 168 days in July where the temperature was over 30 C. Between 2000 and 2009, there were 189. 

But the next set of numbers is alarming, he said. In the 1960s there were only 21 nights where the minimum temperature in July was over 20 C. But from 2000 to 2009, that number rose to 109.

And that phenomenon is not just occurring in Toronto, but across many parts of the world, he said.

“Over the past 130 years night-time minimum temperatures are increasing,” said Pacheco. The rise in night-time temperatures is not the only factor that affects people in a heat wave, she said, “but it’s more significant when there is an extended heat event.”

Her advice for those that don’t have air conditioning is to take cool showers, baths, mist themselves with cold water, drink lots of water, minimize the actual time outdoors, close blinds and drapes to block out the sun, avoid using the oven, visit a place with air conditioning so you can get some relief.

--Debra Black, Staff Reporter

Outlook for this summer's weather? Cloudy with a chance of accuracy

Was Tuesday's hot, dry weather a taste of what the GTA can expect this season? Maybe, maybe not. Depends on who you ask. (KEITH BEATY/THE TORONTO STAR)

Canada’s two leading weather forecast services released their predictions for the summer this week, and wouldn’t you know it? They don’t agree.

The Weather Network predicts overall average temperatures and precipitation. Environment Canada, meanwhile, calls for a warmer, drier summer for much of the country and the GTA.

In fact, the entire summer forecast is more like an outlook, they say. The forecast is really not specific, nor does it focus on a single spot. Instead, the summer forecast – er, outlook – simply provides the personality or character for the upcoming season.

“We have three categories. I mean, talk about generalities. It’s either going to be warmer, colder or in-between,” said David Phillips, senior climatologist with Environment Canada.

“I would never plan my outdoor wedding ceremony or my crop harvesting based on a seasonal forecast.”

How the summer’s weather will shape up is one of those questions that everyone asks, even though they know that no forecast is 100 per cent accurate, says Chris Scott, a meteorologist at The Weather Network.

“People know you’re going out on a limb on this, they still want your best shot,” he said.

Scott’s prediction is based on the belief there will be some fluctuation in temperatures at the start of the season, such as we’ve seen this week, said Scott.

“People should be prepared for getting those shocks of warm weather where it’s quite hot and then cooling down and often times in between, we do get showers and storms,” he said.

Within those transitions from hot to cool, Scott says Toronto may see a bit more rainfall that usual, but not as much as a couple of years ago when the city experienced a wet summer.

Over at Environment Canada, Phillips is more confident in the temperature prediction than the guesses about rainfall.

“It really blows you out of the water,” he said. “There’s just really not a lot of skill in precipitation forecast. We issue it because people want it.”

Predicting summer rainfall is difficult, said Scott, because you can get a heavy storm in one area of the city, while at the other end, the weather is just fine.

In the end, Scott says meterologists can only go as far as science will take them. They don’t provide a precise forecast for a certain day because it is impossible to do, he added.

Instead they try to glean the future by examining the past. “We’re looking at history, looking at previous years, we’re looking at what’s happened in the spring. We’re looking for clues in the atmosphere and especially the oceans,” Scott said.

Canada is difficult to predict, added Phillips, because the country’s weather is so variable.

Seasonal outlooks are simply a matter of satiating curiosity, Phillips said – especially after a dreary spring like the GTA experienced this year. People want to know if there will be light (and sun) at the end of the tunnel.

Of course, other forecasters can offer varying predictions, he said. Sometimes Environment Canada is right, sometimes it’s wrong, but it handles weather in its own way.

“There are different forecasts out there, just like there are different economic models. There are different weather models too,” Phillips said.

The Weather Network’s Scott agrees. “At the end of the day, no two forecasts are alike.”

--Aleysha Haniff and Amanda Khan, Staff Reporters

Colder than normal spring forecast

Ontario's Wiarton Willie, Nova Scotia's Shubenacadie Sam and Pennsylvania's Punxsutawney Phil all predicted an early spring.

But Environment Canada's spring forecast suggests the rascally rodents got it all wrong.

The agency is out with its spring forecast for March, April and May.

Last year, Canada had one of the earliest springs ever, noted senior climatologist David Phillips, but this year, the season will be "reluctant to arrive."

Canada has had a "fickle and fitful" winter with temperature swings that are typical in a La Nina year, he said, and there will likely be more of the same in the spring.

About three quarters of the country will be colder than normal for the next three months, according to Phillips.

"March is going to roar in like a lion in parts of the Maritimes where they're talking about heavy snowfall and blizzard kind of conditions," said Phillips.

"On the Prairies it's more like frozen mutton because they're going to see one of the coldest beginnings to March they've ever seen across that region," he said.

Temperatures will be 18 to 20 degrees colder than normal Tuesday and Wednesday on the Prairies, he said.

British Columbia, the Yukon, the Prairies, the Northwest Territories, most of Ontario, and a good chunk of Nunavut will see colder temperatures during spring.

"We've done a lot of plowing and shovelling and pushing in some areas of Canada and it looks like they're going to continue that," said Phillips.

Eastern Nunavut, most of Newfoundland and eastern Nova Scotia will enjoy a warmer than normal spring.

Western Nova Scotia, New Brunswick, Labrador, southern Quebec and eastern Ontario will have near normal temperatures, he said.

Southern B.C., most of Ontario, Quebec, Atlantic Canada and Nunavut will see a wetter than normal spring while precipitation will be near normal in northern Ontario and most of the Prairies.

But at least Canadians have something to put themselves in a sunny mood.

Residents in the southern half of the country are gaining about four minutes a day more daylight driving to work or heading to school, he said.

"This is the time of the year where the day length just gallops from one day to the next," said Phillips.

"That really lifts our spirit. Even though nature doesn't want to give us the spring that we think that we deserve, we see it in the daylight and that can be uplifting," he said.

-- The Canadian Press

Photos: Gulf Stream bypasses the U.K.

The sun sets over the sea looking towards Lands End viewed from Gwenver beach near Sennen Cove on Feb. 7, 2011 in Cornwall, England.

Like many parts of the U.K., Cornwall is currently enjoying milder weather after what has been one of the harshest winters on record.

Normally, the Gulf Stream, which brings warm air from the Caribbean, makes Cornwall's weather a lot milder than other places in the world at the same latitude (such as Newfoundland) and gives it the U.K.'s only area of sub-tropical climate.

This winter however, the Gulf Stream was diverted, leading to arctic weather conditions. (Photos by Matt Cardy/Getty Images)

2010 tied for warmest year on record: UN

A cooling centre set up in Metro hall in July of last year. (TARA WALTON/TORONTO STAR FILE PHOTO)

GENEVA — Last year tied with 1998 and 2005 for the warmest year on record, providing further evidence that the planet is slowly heating up, the UN weather agency said Thursday.

Arctic Canada took one of the biggest hits, with parts of the region experiencing their hottest years on record, according to the World Meteorological Organization.

Eastern Canada was also “exceptionally” warm in December 2010, the agency wrote in a release.

The agency said average temperatures around the world last year were 0.53 Celsius above the 1961-90 mean.

“The 2010 data confirm the Earth's significant long-term warming trend,” said Michel Jarraud, the agency's top official, adding the 10 warmest years since records began in 1854 have all occurred since 1998.

WMO's figures are based on data collected by Britain's Meteorological Office, the U.S. National Climatic Data Center and NASA.

The recent warming has been especially strong in Africa, western Asia, Greenland and parts of the Arctic, according to the agency.

Arctic sea-ice cover in December 2010 was the lowest on record – 1.3 million square kilometers below the 1979-2000 December average, the agency said.

The weather was a different story in northern and western Europe, as it was “abnormally” cold, the agency said.

Central England experienced its coldest December since 1890, and temperatures in Norway and Sweden were as much as 10 C below normal.

The Geneva-based global weather agency also noted that last year's extreme weather — notably the heat wave in Russia and monsoon flooding in Pakistan — has continued into the new year.

It cited heavy floods in Sri Lanka, the Philippines, Brazil and Australia as examples.

With files from Associated Press

The Kremlin wall is seen through heavy smog, caused by peat fires in nearby forests, in Moscow in August. (Alexander Natruskin/REUTERS FILE PHOTO)

From floods to snowstorms, blame La Nina

A parked car is buried in snow following a winter storm in Toronto last week. (Darren Calabrese/THE CANADIAN PRESS FILE PHOTO)

If you think this year’s winter is a bit harsher than those in your recent memory, blame La Nina.

Environment Canada says the weather phenomenon has been wreaking havoc around the globe — and having an effect here at home.

“We’ve already had more snow this winter as we had all winter last year,” said David Phillips, senior climatologist.

La Nina, which Phillips describes as “the nasty sister of El Nino,” is the result of the cooling of the Pacific Ocean along the equator and the subsequent changing of wind patterns.

For Canada, this generally leads to colder and longer winters as systems come in from the northern air masses, although Ontario is not usually affected as much as the western provinces.

“What we see is more cold spells and a bit more snow, but it varies,” said Phillips. According to Phillips, the winter may even be a little longer than the last, with the possibility of snow into April.

“It is good for skiers, not good for people who want to save money on their home heating bills,” said Phillips.

La Nina tends to come every three to seven years; scientists are never able to predict its arrival, only what may happen once it’s here.

“It affects the weather around the globe,” said Phillips. “Some of the floods in Brazil, Sri Lanka and Australia are directly related to La Nina.”

Raging floodwaters have swamped thousands of homes and businesses in Queensland, leaving at least 25 people dead and dozens more missing since late November. Rail lines and highways have been washed away in what is shaping up to become Australia's costliest natural disaster.

The flooding follows a spate of severe natural disasters in the past year. While the most deadly was Haiti's earthquake, extreme weather also killed thousands of people across the globe, including a scorching heat wave that choked Russia in the summer and devastating floods that engulfed more than 150,000 square kilometres in Pakistan.

The effects of La Nina can last anywhere from six months to 18 months. El Nino, on the other hand, is the result of temperatures rising in Pacific Ocean along South America, and brings Canada much shorter and warmer winters like that of last year.

“What’s been unusual this year is that it went from El Nino to La Nina almost overnight,” said Phillips, explaining that there is usually a transition period of neutral ocean temperatures between the two.

With files from The Associated Press

This aerial photograph shows residential suburbs inundated as flood waters devastate much of Brisbane on Jan. 13, 2011.(TORSTEN BLACKWOOD/AFP/Getty Images)

Bizarre weather? Blame 'rollercoaster' jet stream

A snowplow is driven on the second runway, in an attempt to get it operational again, at Heathrow Airport on Dec. 21, 2010. (ADRIAN DENNIS/AFP/Getty Images)

Parts of Europe may be getting the cold shoulder, but parts of Canada have been experiencing abnormally warm weather.

There have been record-breaking temperatures in parts of northern Canada like Iqaluit, which has had its warmest year ever.

Why London is snowbound, and Toronto isn't

London is still buried in snow and much of the city has ground to a halt, but the mayor will not be declaring a state of emergency. “I’m not calling in the army,” said Mayor Joe Fontana.

But he will be shutting down the public transportation service as of 3 p.m. Tuesday evening. He’s asking employers to give their workers time off or the opportunity to work from home. And he is urging young people to knock on their neighbours’ doors, offer to shovel and go for groceries.

Fontana said more snow has fallen in the past two days than in any two days in the city’s history. The city has borrowed snow removal equipment and crews from neighbouring municipalities.

“Every time we seem to clear the main roads, we’re having to go back into them,” he said.

“Our people have been working day and night.”

So far there have been no power outages or serious injuries. And surrounding municipalities have been largely spared the onslaught.

“It seems to be stalled over London. I don’t know why we’re so lucky,” mused the mayor.

David Phillips, a senior climatologist at Environment Canada, said it’s the “lake effect.”

“You drive 15 minutes away and you can see green grass,” said Phillips.

“Talk about a world of difference.”

Why? It’s the lake effect snowstorm, snow burst or “streamer” effect.

What is it? At this time of year the Great Lakes are much warmer than the air above them, said Phillips.

The air sucks moisture out of the lake and then moves over the land, where it dumps out the moisture in the form of snow.

These “streamers” only form when there is a very steady wind pattern, he said. How does it work? In this case, the wind has been blowing in the same direction (west-northwest) for several days in a row.

The streamer drifting off Lake Huron is now “locked in” over London, said Phillips, and the snow continues to fall.

These bands of air are often very narrow, which explains why one city can be experiencing whiteout conditions, while the next town over has only a light dusting of snow.

Last year London had about 108 cm total.

Are we next? No, said Phillips, because Toronto isn’t usually downwind of Lake Ontario. Toronto can experience lake effect snow bursts, but only if the wind is moving in an easterly direction which isn’t common. But there is a traditional snowstorm heading north from the United States.

It’s too early to predict how much snow will get dumped on Toronto, but look for flurries beginning this Sunday.

-- Cynthia Vukets, Staff Reporter

 

Toronto should expect stormier, colder winter

The city looks snowed in from the front of the Ward's Island ferry in this file photo. Torontonians can expect typical winter conditions this year. (Richard Lautens, Toronto Star)

Torontonians will experience a return to typical winter conditions this year, thanks to the La Nina effect.

“After last year, where we got off very easily across our region, we’re back into a little more winter this year,” said Chris Scott, meteorologist and Weather Network forecast operations manager.

Scott said the GTA normally receives about 120 cm of snow over the course of a winter but last year the city saw less than half the amount. This year, Toronto is predicted to receive more than 1 m of snow.

The city should expect stretches of a couple of weeks where there will be storms every three or four days bringing in snow, Scott said.

According to the Weather Network’s outlook for the months of December, January and February, Toronto’s average low will hover around -9 C with an average high of -1 C.

“We think there’s going to be some fairly significant cold snaps with some fairly significant warm spells in between,” Scott said.

The city can expect average precipitation of about 156 mm.

However, parts of southwestern Ontario should prepare for more precipitation than usual.

“Normal” conditions are calculated by looking at data over a 30-year period, according to the Weather Network’s website. The network’s 2010-11 outlook used data collected between 1971 and 2000 to calculate normal temperatures and rates of precipitation.

Scott said last year’s mild winter was due to the El Nino current, which produced big storms in the U.S. but gave Canada almost the opposite effect.

This year, with La Nina, we can expect a stormier season with more extreme changes in temperature.

“I like to think of her as the dinner party guest with a really big personality,” he said. “There’ll be lots of ups and downs and swings.”

--Gloria Er-Chua, Staff Reporter

The city looks decidedly snowed in from the front of the Ward's Island ferry. The winter weather continues in Toronto with up to 15 cm of snow due to fall today. Ward's Island is similarly hit and looks like a winter wonderland. Richard Lautens, Toronto Star

Credit: Toronto Star

Byline: Richard Lautens

Predicting hurricanes under goes a sea change

Climatologists say they have cracked the code for predicting hurricanes up to 10 years in the future.

And in what is certain to be controversial, they’ve done it by using a climate prediction model that factors in internal as well as external factors.

That means “external” factors such as greenhouse gases, volcanoes or aerosol sprays are part of the reason for the increase in one of nature’s most destructive forces.