On Thursday, a treacherous one-two punch of heat and fire, compounded by the oil and gas fire, scorched a large swath of North America, killing at least 15 people in the United States, making countless others ill, closing schools and testing the basic services that remain unprepared for the new profiles of the summer.
Yet it is only June.
In the United States, a heat dome stretched from Texas to Florida to the tip of Missouri, raising the heat index — a combination of temperature and humidity — to well over 110 degrees Fahrenheit in some places.
No immediate respite was in sight. Temperatures are expected to rise 15 to 20 degrees above normal across much of the region over the weekend.
And a new heat dome was expected to form over California in the coming days. Sacramento and the San Joaquin Valley, a region where thousands of farm workers toil outdoors for hours, are on alert for excessive heat, the weather service said.
Across Canada, hundreds of fires continued to burn, drawing 1,500 firefighters from around the world.
In Toronto, air quality was, briefly, the worst in the world, as smoke from wildfires from other parts of Canada blanketed the city and spread rapidly southward, shrouding the eastern United States in a toxic soup. In Washington, DC, the National Gallery has closed its outdoor sculpture garden.due to air quality.“
In Mexico’s northern state of Nuevo León, schools closed on Thursday, about a month ahead of schedule, after temperatures reached 113 degrees Fahrenheit in Monterrey, the state capital. “To take care of the children, who are a priority, we decided it wasn’t worth putting their health at risk,” Governor Samuel García Sepúlveda said.
Kim Cobb, climate scientist and director of the Brown Institute for Environment and Society, said the week’s events embody the “multiple stressors related to man-made climate change” that the United Nations has put warned through its science group on global warming. “If ever there was a time to stop and reevaluate our fossil fuel emissions trajectory, that time is now,” she said.
Both extreme heat and wildfires are exacerbated by greenhouse gas emissions from burning fossil fuels. Not only do these emissions make heat waves that could occur naturally more extreme, they can also intensify droughts that fuel catastrophic fires.
Temperatures around the world in June hit their highest levels in decades, reflecting two things: climate change driven by accumulated emissions of heat-trapping gases and the three-year return of the natural climate pattern known as El Niño . Meteorologists say it could usher in a multi-year spell of extreme heat.
For nearly half of the United States, predictions for the heat index, a measure of how temperature actually feels, fall into the categories of “extreme caution” or “danger.” Humid air can prevent the body from cooling efficiently because the air is so saturated that the moisture from a person’s skin cannot evaporate, a necessity for cooling.
Adding to the danger, nighttime temperatures are expected to remain high this week in the South and Midwest, making it harder for the human body to have a chance to cool down.
In downtown Jackson, Miss., where the heat index hit 113 on Thursday, workers replacing a sewage pipe took turns working in the sun for 30 minutes at noon, resting under a tree in between. “My advice to anyone is to find some shade,” said Cody Adams, a worker at Miller Pipeline, an infrastructure company. “Drink lots of fluids before you go out. It’s hot out here.
Extremely dangerous heat stress is likely to persist into Saturday in Jackson, forecasters said, warning of heatstroke risks with prolonged outdoor activities.
In Dallas, where the heat index clocked in at 103, workers were out fixing air conditioners that had overheated and blowing out warm rather than cold air. “Compressors fail left and right,” said Natalie Ortiz, owner of Alpha Heating & Cooling. As of Thursday morning, she had replaced four times as many air conditioner compressors as she did all summer in a typical year.
“It’s not normal. We just started summer,” she said.
While parts of Texas may finally return to near normal this weekend, parts of South Texas and locations near the Gulf of Mexico will continue to experience oppressive temperatures through Sunday.
Heat-related deaths are notoriously difficult to explain precisely, because heat can exacerbate pre-existing conditions such as kidney and heart disease. However, the first casualty figures were beginning to emerge.
In Webb County, Texas, one of the hardest-hit parts of the country, the immediate death toll from the heat rose to 10 by noon Thursday. In Laredo, which is part of Webb County, the heat index was 109 degrees Thursday and is expected to rise to 114 on Friday.
Mexico has signed up at least 112 heat-related deaths so far this year, with more than half of those occurring in the state of Nuevo León, according to the health ministry. This compares with just four recorded heat-related deaths same time last year nationwide.
Temperatures in the northwestern Mexico city of Hermosillo are expected to hover around 109 degrees over the weekend, after rising to 121 degrees on Sunday, among the highest temperatures recorded anywhere in the world that day.
It was the third heat wave of the year in Mexico.
Dan Bilefsky contributed reporting from Montreal; Mary Beth Gahan of Dallas; Jimmie Gates of Jackson, Miss.; Delgar Erdenesanaa, Judson Jones, Anushka Patil, Elena Shao and Raymond Zhong of New York City; and Emiliano Rodriguez Mega and Simon Romero of Mexico City.