It's arguably the worst timing for a massive power outage in South Florida. This year is on track to be Miami's warmest on record. The month of July was the hottest the city has ever recorded. Without air conditioning, South Florida weather is oppressive at best and downright dangerous at worst.
But on Monday afternoon, 6.1 million customers were without power in the wake of Hurricane Irma, according to the Department of Energy. By Wednesday morning the number of outages was down to 3.5 million — but still more than a third of the state.
The lack of power is by far the largest lingering effect of the storm which is now long gone. The clouds have parted, and the sun is back. So is the heat. Without air conditioning, South Florida is a sauna.
It's no Category 4 hurricane, but over the past decade, heat has been the second-most deadly weather phenomenon — on par with flooding and tornadoes.
In 1995, Chicago experienced one of the most tragic weather events in U.S. history — and easily the deadliest Chicago has ever endured. More than 750 people died over the course of a week as temperatures climbed into the triple digits. Notably, overnight lows did not drop below 70 degrees.
As the Chicago Tribune reported, the victims of heat illness tend to be "mostly the poor, elderly and others on society's margins." Air conditioning could have saved these lives, but — even in 1995 — a large portion of the population didn't have access; "thousands who had them couldn't use them because of power failures, and still others couldn't afford them," the Tribune wrote.
Cook County Hospital didn't even have air conditioning, the Tribune reported.
"We had some patients with cardiovascular problems who literally developed heatstroke while they were in the hospital," Cory Franklin, the director of intensive care at the hospital, told the Tribune 20 years after the heat wave. "That is almost unprecedented … the only other time I've ever heard of that happening was during Katrina at Charity (Hospital) in New Orleans."
Although utility companies are working night and day to restore power, millions are still without electricity and air conditioning this week as high temperatures approach 90 degrees. Overnight lows will be close to 80 through the weekend.
On any other day those temperatures wouldn't make headlines. Without electricity, they're of critical concern, said Scott Sheridan, a professor of climatology who studies heat illness at Kent State University.
At particular risk, Sheridan said, are the vulnerable groups who are used to being in a climate-controlled environment — like a nursing home or another health facility — and are all of a sudden thrown into sauna-like conditions. As our bodies age, our "thermo-regulatory system" becomes less efficient.
Basically, the older we get, the less our bodies are capable of cooling.
"To be suddenly out of that [air conditioning] — even if temperatures don't sound record-breaking — it may be an environment these people are not accustomed to at all," Sheridan told The Washington Post.
And the actual manifestation and impact of the heat may not be heat stroke or heat exhaustion, said Laurence Kalkstein, a voluntary professor at the University of Miami's Department of Public Health Services.
People who die during heat events "die of heart attacks, stroke or respiratory failure — not heat stroke or exhaustion," Kalkstein told The Post.
"Older people are generally weaker, on medications, out of shape and living a lifestyle that is not conditioned to dealing with extreme situations," said Kalkstein. "That makes them much more susceptible to begin with."
On top of all that, he said, "they are less aware of their surroundings, and some don't even realize they are overheating."
Unfortunately, prevention depends on technology, Sheridan said, particularly air conditioning. But in an emergency situation like a hurricane, there's no redundancy in the system.
But "if there are power outages, it may be impossible to move to a cooler location," Sheridan said. "Because of the emergency itself, you're not able to move readily, you're physically unable or there's just no cooler location."
Sheridan recommends frequent cool baths and staying hydrated for people without air conditioning — assuming there is ample clean water available.
"Most critically, make sure people are checked up on," he noted. "In large heat events, people are far more susceptible if they're socially isolated."
Capital Weather Gang's Jason Samenow contributed to this post.