City of Toronto issues the sixth heat alert of the season

Those who have this Simcoe Day off can look forward to a hot one: the City of Toronto has issued a heat alert today.

Temperatures will climb to 33 C today, but will feel more like 37 C. There’s also a piping UV index of 9, or very high, according to Environment Canada.

Toronto Public Health staff monitors its heat health alert system to determine whether a heat alert should be issued . The system compares forecast data to historical weather conditions which have led to increased mortality in Toronto in the past.

Factors taken into consideration include conditions like temperature, dew point, humidity, cloud cover, wind speed and direction.

This is the city’s sixth heat alert of 2011. July was the hottest July on record for the City of Toronto with an average temperature of 24.37, according to Dave Phillips, a climatologist with Environment Canada. That beat out the previous record of 24.3 in 1999.

And the warmest day the city has ever seen was this past July 21, when the mercury rose to 37.9 C. The average temperature for the day was 32 C, which beat out a previous record of 31.5 C on Aug. 1, 2006.

“If you stuck a thermometer in Toronto this past July, it would say well done,” Phillips said.

The warmest temperature ever recorded at Pearson was 98.3 on Aug. 25, 1948.

At the rate we’re going, this summer may beat out the summer of 1955 as the hottest Toronto has ever seen. August is expected to mirror the record-setting July we just had, which was not only the hottest July, but also hotter than any June of August the city has ever seen, according to Phillips.

The average temperature for July and August combined in 1955 was 23.6 C. “We are now at 24.4 C, so we could be a degree cooler in August and still break that record,” he said.

July was certainly one for the books in more ways than one. There were 16 days where the average temperature hit above 30 C, and we usually only have 6. We had 30 hours more of sunshine than average, and we only received 43 per cent of what we’d normally get in terms of precipitation—we had 32.4 mm of rain, when we normally have an average of 74.4. July dragged us through a 14 day dry spell as well.

“It was a scorcher. Toronto was well done, baked, grilled roasted.

“It was the hottest day ever, it was the hottest month ever, I mean, you run out of superlatives talking about this particular month.”

In recent memory, the hottest summer Toronto has seen was 2005. The average temperature for July that year was 24.1. That year also had a number of smog days, with 12.5 in July alone. Phillips said there were probably more than 30 smog days throughout the duration of that summer.

In 2005, there were 10 nights on which the temperature remained above 20 C, compared with the 12 we had last month, which brings us to a trend Phillips said is gaining momentum.

“What’s really different in Toronto these days is the warm nights. It’s a hot time in the old city.”

He chalks the sultry summer nights up to increased urban development.

“The city is just getting warmer and cloudier, there’s more heat being trapped in.”

In terms of heat this holiday Monday, Phillips said we shouldn’t rule out the possibility of a humidex advisory being issued. Right now the humidex sits at 37 C, and advisories are issued when it hits 40 C.

The city is urging people to drink lots of water, go to air conditioned spaces and try to stay out of the sun.

In stark contrast to the sweat bath we’re in now, the lowest average temperature for a Toronto summer on record is 17.7 C, and that was in 1965.

— Sarah Ratchford, Staff Reporter

Heat alert extended

The extreme heat alert has been extended in Toronto as temperatures are expected to hit a scorching 34 C today, feeling more like 40 C with humidity.

This is the fourth day in a row that the city has been under an extreme heat alert.

To make matters worse, the city hasn’t seen substantial rainfall since July 3. There were light showers Friday night but it was “just a sprinkle” — not even enough to measure, according to Tony Cham, a meteorologist at Environment Canada.

Since the start of July, Toronto has seen only 4.4 mm of rain when the norm for this time of the year is about 74.4 mm.

The driest July ever was set in 1957 with 11.4 mm of rain.

Cham says it is hard to predict whether Toronto will break the record this year since there are still nine days left until the end of the month.

But relief may be in sight.

There is a 30 per cent chance of showers Saturday evening and a 60 per cent chance of rain Sunday night into Monday morning.

“There’s still some hope,” Cham said.

Meanwhile, to cope with the extreme heat, the city has opened cooling centres across Toronto and some city pools may extend their operating hours.

Much of the United States and Canada are trapped under a heat “dome” caused by a huge area of high pressure that’s compressing hot, moist air beneath it and keeping the jet stream well to the north.

This high-pressure system is leading to scorching temperatures like the ones Toronto saw Thursday when the mercury hit a sweltering 37.9 C, the highest July day temperature ever recorded at Pearson airport but just shy of the 38.3 C record set on August 25, 1948.

The smog that sometimes accompanies hot weather is nowhere to be seen, though. The city’s only had one smog day this summer. In 2005 — a similar year temperature-wise — there were 20 by this time.

There have been fewer smog days partly because of improved air quality, said Kate Jordan, a spokesperson for the Ontario Ministry of Environment.

In the past eight years, the province has seen reductions in fine particulate matter and nitrogen dioxide — the two main ingredients in smog, Jordan said. But weather also plays a role. “While we’ve had really warm and sunny weather, we haven’t had stagnant air pressure and the hazy conditions,” she said.

This is because the winds blowing through Toronto are not coming from the south, which typically brings in dirtier air and higher humidity, she adds.

 

When is a temperature record not really a temperature record?

Will Thursday’s temperature soar to a record level?

Well, the answer to that could depend on which statistics you use.

According to measurements taken at Pearson airport, Toronto’s heat record was set on Aug. 25, 1948 when it was 38.3 C.

Measurements at Pearson started in 1937. In 1936, downtown temperatures on July 9 were measured as high as 40.6 C, and the temperature reached 40 C three times between July 8 and 11.

But those measurements are less reliable and shouldn’t be considered the record high, said David Phillips, senior climatologist at Environment Canada.

“Downtown, it’s hard to get the numbers right,” he said. Using downtown measurements alongside those at Pearson is “like comparing apples with oranges,” he added.

The reliability issue comes in partly because of the urban heat island effect, which is mostly caused by heat-retaining materials such as asphalt and concrete. In addition, the downtown measurement site at the University of Toronto has changed places since 1936, whereas Pearson’s hasn’t, Phillips said.

The official record, then, is that 38.3 C day in August 1948.

Even if today’s mercury doesn’t crack 38.3 C, it could still be Toronto’s hottest-ever July day. That benchmark was set on July 7, 1988, when it reached 37.6 C.

-- Michael Woods, Staff Reporter

Thursday may be Toronto's hottest day ever

(Hajop Ohannessian of Toronto practices yoga along the shore of Lake Ontario on Tuesday. With temperatures reaching the upper 30s many Torontonians are heading to the water for some hot weather relief. TARA WALTON/TORONTO STAR)

Keep your fan on high and your water bottle handy: Thursday could be Toronto’s hottest day ever.

The temperature is expected to reach a scorching 38 C. Toronto has only been that hot once, when it reached 38.3 C on August 25, 1948 according to measurements at Pearson airport.

Factor in the humidex and Thursday will feel like somewhere in the mid to high 40s.

If it doesn’t quite beat 38.3, Thursday could still be the hottest July day on record, beating out the 37.6 C high on July 7, 1988. Temperature records at Pearson have been kept since 1937.

Friday is projected to cool down to a more reasonable 32 C, but highs above 30 C are forecast through the weekend.

“We’re talking about excruciating temperatures,” said David Phillips, a senior climatologist at Environment Canada. “It’s very unusual.”

Overall, nine days this month have reached temperatures higher than 30 C. “We’ve already had a year’s worth of days above 30,” Phillips said.

The extreme heat is caused by a high-pressure system sitting over the city that’s warding off weather and keeping the jet stream well to the north, Phillips said.

The smog that sometimes accompanies hot weather is nowhere to be seen, though. The city’s only had one smog day this summer. In 2005 — a similar year temperature-wise — there were 20 by this time, Phillips said.

There have been fewer smog days partly because of improved air quality, said Kate Jordan, a spokesperson for the Ontario Ministry of Environment.

In the past eight years, the province has seen reductions in fine particulate matter and nitrogen dioxide — the two main ingredients in smog, Jordan said.

Reflecting the soaring temperatures, city officials expect to issue an extreme heat alert Wednesday which will likely last until Sunday.

Dr. David McKeown, the city’s medical officer of health, said elderly people, those with medical conditions and isolated people without air conditioning are most at risk during prolonged hot periods.

“I am asking everyone, including landlords, to check on those at risk,” he said.

If an extreme heat alert is called, Toronto Public Health will open seven cooling centres across the city. Some city pools may extend their operating hours.

EMS chief Paul Raftis said it’s important for people to drink water, avoid too much outside activity between 11 a.m. and 4 p.m., and check up on family and friends for symptoms of dehydration.

The coroner’s office reported six deaths from heat-related causes last year in Toronto. But Dr. McKeown said statistical analysis shows an average of about 120 deaths per year from heat-related causes.

No such deaths have been reported this year.

Those in need of assistance can call the Canadian Red Cross heat information line at 416-480-2615, between 9 a.m. and 9 p.m.

— Michael Woods, with files from Amanda Kwan

GTA cooking under week-long heatwave

An employee from an outdoor eatery hangs a revised menu in Minneapolis July 18, 2011.(Eric Miller/REUTERS)

After one of the wettest springs on record, Toronto is now under a dry spell with no relief in sight.

In the last 25 days, the city has seen only 6.4 mm of rain when we should normally have gotten 63 mm, said Dave Phillips, senior climatologist at Environment Canada.

“We’ve had a tenth of what we normally would get in a three-and-a-half week period,” he said.

But Phillips doesn’t expect the record for the driest July — which was set in 1957 with 11.5 mm of rain — to be broken this summer.

“You can get one gullywasher, you see, and a record won’t be set.”

Record or not, Phillips says, it’s dry in Toronto and next week’s forecast doesn’t look much wetter.

There is a 30 per cent chance of rain on Sunday or Monday but Phillips it’s unlikely the sky will bless us with moisture.

“I don’t even carry an umbrella for 30 per cent chance. It’s not a done deal. We’re in it for the longhaul,” he said.

The last substantial rainfall was in June, and ironically, it was on the first day full day of summer when Toronto saw 21 mm of rain. The day before, we got 15 mm.

“In that two days, we had 36.4 mm of rain. That was a significant dose of moisture — almost what you’d expect in half-a-month, we got in two days. Yet over the last 25 days, we can barely get a thimble full of rain,” said Phillips.

“Could you imagine what Toronto would look like if we didn’t have one of the wettest springs on record?”

The lack of rain and cloud cover is turning the city into a sauna.

The city has extended a heat alert today, which will likely be the coolest day of the week at 30C with a UV index of 9, or very high.

Thursday is set to break records with a high of 38C, feeling more like the mid- to high 40s with the humidex reading. The mercury will drop toward the weekend, but only slightly, hovering around 30C.

The city advises residents to drink plenty of water, avoid going outside during peak sun hours, wear loose clothing and limit physical activities.

Phillips’ advice to Torontonians: be kind to trees.

“Be good Samaritans. Hug and adopt a tree and water it because it will please you later on when it bursts forth with brilliant colours in the fall.”

Amanda Kwan, with files from Zoe McKnight

• TOP 6 HOT WEATHER PHOTOS:

1. Participants in Drums Across Kansas, featuring eight elite drum and bugle corps from around the country, take a water break in Valley Center, Kansas.

(Mike Hutmacher/Wichita Eagle/MCT)

2. Gymnasts play in a fountain to cool down in hot weather, on the second day of the World Gymnaestrada in Lausanne.


(Valentin Flauraud/RETUERS)

3. Youths jump into the water at Laaerbergbad swimming pool on a hot summer day in Vienna.


(Lisi Niesner/REUTERS)

4. Estella Willis, left, and Joshua Boardman beat the heat as they cool down under a garden hose in the town of Hudson, Que., near Montreal.


(Graham Hughes/CANADIAN PRESS)

5. Declan Lee-Smith, from Sydney, Australia, tries to beat the heat by surfing the rapids along the St. Lawrence River in Montreal.


(Ryan Remiorz/CANADIAN PRESS)

6. Jazia Pratt, 8, fills a bucket with water from a fire hydrant in the afternoon summer heat in Philadelphia.


(Matt Rourke/ASSOCIATED PRESS)

Southwestern U.S. headed for a ‘perpetual drought’

A family looks on as a dust storm converges on downtown Phoenix, July 5, 2011. (Mark J. Rebilas/US PRESSWIRE)

A 160-kilometre wide dust storm, corn shrivelling in Georgia fields and Texas blackouts are all harbingers of an unstoppable force geophysicists call "perpetual drought."

At least the terrible Dust Bowl years of the 1930s in North America ended, Dr. Richard Seager told the Toronto Star on Thursday. This one won’t.

The U.S. Drought Monitor computer tracking tags the parched conditions in Texas and Oklahoma as an extraordinary drought, with the rest of the stretch from Arizona to Florida not much better.

Losses in Texas alone, to cattle and wheat, could reach $3 billion U.S., state officials said. Rainfall in Oklahoma is 28 per cent of normal.

In parts of Arizona, it’s half of what it should be. The July 5 dust storm, the worst in 30 years, shut down Phoenix Sky Harbour International Airport and coated the city in a crust of dirt.

All 254 counties of Texas have been declared natural disaster areas. In some place, salt buildup on power lines not swept away by rain has caused blackouts.

“The current drought has been running for less than a year,” said Seager of the Earth Institute at Columbia University. The cyclical arrival of the La Niña weather pattern brought it and will eventually move on.

But more ominous and catastrophic is the permanent spike in temperatures that is making southwestern North American too feeble to bounce back.

“Beyond the year-to-year variability, the entire region from California to the southern plains is getting dryer. It may not be more severe than what we have now, but it will be more persistent,” Seager said.

By the middle of this century, he said, the drought state of the southern United States will be permanent.

“There will still be wet years. There will be dry years. But the net flux, which supplies the moisture to the soil, is going to reduce from 20 to 40 per cent.”

Unlike the Dirty Thirties drought, which lasted seven years, the decade-long drought in the 1950s or even the “megadroughts” of the 13^th and 16^th centuries — all of them La Niña phenomena — this one is triggered by man-made gases.

“As long as the carbon dioxide in the atmosphere stays where it is, we have a new equilibrium,” said Seager.

Even if all CO² emissions dropped to zero overnight “significant drying would still occur.”

And while farmers have compensated for dry spells since the 1930s with irrigation, it’s an expensive and gasoline-burning way to spread water around.

“As the century progresses, it will be harder and harder to keep the productivity up.”

- Lesley Ciarula Taylor, Staff Reporter

Temperatures are soaring, so why no heat alert?

Toronto has been sweltering for the past couple of weeks with no reprieve in sight, but the city has yet to issue an official heat alert.

George Matsumura, a spokesperson for Toronto Public Health, said there are a number of factors besides the heat to consider when deciding whether to issue a heat alert.

Those factors include wind speed, dew point, humidity and cloud cover, as well as the number of consecutive hot days.

Just because it’s 39C outside doesn’t mean an alert will be issued. If it’s 39C, there’s no wind, and there is a “humid, moist, tropical air mass,” though, it is likely that there will be an official alert.

“It’s not a simple thing,” he said.

Matsumura said the key factor in a heat alert is mortality. When it’s difficult to breathe outside due to heat and humidity, older people and small children, as well as others with health concerns like diabetes, can be in serious danger.

While there have been no official alerts this month, there hasn’t been much of a break from the heat so far this summer. Toronto has had 4 mm of rain this month, and July generally gets about 74 mm on average, said Peter Kimbell with Environment Canada.

“It’s been almost two and a half weeks now with very little rain, so the question becomes ‘How long can we go with very little rain?’”

He said there might be a chance of some rain Sunday or Monday, but can’t say so for sure.

This hot dry weather makes a lot of people grumble about heat waves. The city’s term for heat waves is “extreme heat alert,” of which there have been none so far this year. There were 11 last year, compared with only two in 2009.

“We don’t have a very well-defined criteria for a heat wave,” Kimbell said.

“There are varying definitions. The best I can say is it’s going to be sunny and warm the next few days with a good bout of heat and uncomfortable conditions this weekend. Before then we’ll have more pleasant weather where we can sleep at night — lows will be 15, 16, 17 degrees.”

Kimbell added that there is no real explanation for why heat waves happen, other than to say:

“Weather is inherently variable.”

 

Last year there were 11 extreme heat alerts, compared with only two in 2009.

--Sarah Ratchford, Staff Reporter

Humid start to a hot, dry week

Toronto is a week away from the “dog days” of summer but we’re already experiencing the heat.

“We really need some rain,” said Dave Phillips, senior climatologist at Environment Canada.

In the last 17 days, Toronto has had only 6 mm of rain when we normally get 41 mm at this time of the year, he said.

“We’re really down and you can see it. The grass looks more like hay right now.”

The only moisture we’re going to see this week is on Monday, which will be a hot and sticky day with the humidex in the high 30s, Phillips said.

But the good news is that we’ll see winds of 20 km/h today gusting to 40 km/h in the afternoon, which will help evaporate some of the moisture from our skin, he said.

There is also a 60 per cent chance of showers and thunderstorms this afternoon that will alleviate some of the heat, he said.

But the rest of the week will be dry and hot with temperatures in the high 20s and low 30s.

“It’s going to be a delightful week. Is anyone really complaining?”

The long-term forecast includes warmer than normal temperatures and below average levels of precipitation

Even though we need the rain, Phillips says people are afraid to jinx the sunny weather.

“There’s a little nervousness given the wet spring,” he said.

A similar heat wave is hitting the United States this week in the Midwest, the Plains and the Southeast.

Fifteen states are under heat advisories as record temperatures hit as high as 44 C.

-- Amanda Kwan, Staff Reporter

Smog alert issued for southern Ontario

Much of southern Ontario, including Toronto, has been issued a smog alert.

Environment Canada predicts Saturday’s air quality index will exceed 50, which is the threshold for a poor rating.

The partly sunny and hot conditions across the region will combine with pollutants to generate smog, the agency said.

Environment Canada recommends avoiding unnecessary vehicle trips and limiting the use of gas-powered machines such as lawn mowers.

Strenuous outdoor activities could cause coughing or shortness of breath, the agency warns.

Saturday’s daytime high is listed as 29 C, and the UV index is 10, or very high. The forecast called for a 30 per cent chance of showers and the risk of a thunderstorm late in the afternoon.

There’s a chance for more rain this evening, but the weather should clear overnight, with a low of 21 C.

Both pollution levels and the humidex are expected to improve Sunday after a weak cold front rolls in.

Environment Canada predicts Sunday in Toronto will be sunny, with a north wind blowing in late in the afternoon. The daytime high is 29 C.

Humidex advisory in effect for Tuesday and Wednesday

Environment Canada has issued a humidex advisory for the city of Toronto for Tuesday and Wednesday.

The humidex is an index that combines the temperature and humidity into one number to describe how hot the weather feels to the average person.

Environment Canada says that the humidex is particularly significant when its value is greater than 30. Tuesday’s humidex peaked at 38.

Tuesday’s high was 29 C, falling to 21 C overnight, while Wednesday is expected to be sunny with a high of 34 C.

If Wednesday’s temperature reaches its expected high, a record will be set. Phillips said the current record for June 8 is 32.2 C, set in both 1950 and 1959.

The weather on June 8 last year was 20.3 C.

Dave Phillips, senior climatologist with Environment Canada, said that Wednesday’s humidex could be as high as 42 or 43. The UV index will be 9 or very high. Phillips expects the “triple H” — heat, humidity and haze.

Environment Canada warns that a high humidex can lead to health problems such as cramps, exhaustion and heat stroke. They advise people to drink a lot of water, avoid working or exercising intensely outside if possible, and take frequent breaks if necessary.

Environment Canada also reminds people to take special care to ensure that pets have plenty of water, are well-protected from the heat, and are not left in hot cars.

Phillips said that Wednesday will probably be the hottest day of the year so far.

“Get used to it,” said Phillips. “We think there’ll be more of these kinds of days.”