The hot nights are getting more dangerous as Philly’s rowhouses become ‘brick ovens’

Philadelphia almost certainly will set more temperature records over the next two days — but maybe not during the steam-bath afternoons.

Nature’s natural cooling system, nightfall, will have a hard time getting it done with the atmosphere so swollen with water vapor, and forecasters warn that low temperatures the next two nights may stay above 80 degrees, even if the Saturday night storm threat materializes.

That would result in record-high minimum temperatures for the dates in Philadelphia. That record bar is considerably lower than for the high-temperature records — 104 degrees for Friday, and 103 for Saturday — set during the sizzling 1966 Independence week.

Thursday’s high, 103, tied the record set in 1901, when the nation was a mere 125 years old.

Those potential century-plus readings are attention-getting, but health officials have long held that for heat-related mortality, consistently warm nights are more dangerous than the days, particularly for older people who live alone in brick rowhouses in the city. As a former Philadelphia health official has observed, without nighttime cooling, they can become “brick ovens.”

“The intensity and length of the extreme heat will exacerbate impacts to both people and infrastructure,” the weather service warned.

The sequence of hot nights “are particularly harmful because the body doesn’t have a chance to recover,” said Kraftin Schreyer, associate professor of emergency medicine at Temple University’s Lewis Katz School of Medicine. Extreme heat can exacerbate circulatory and lung conditions, and certain mental disorders, she added.

But she and other health experts say the detrimental effects may be modified by the heat the region already has experienced this year.

Friday’s high is expected to challenge the reigning champ, the 104 set during a blistering heat wave in 1966, when the nation was a mere 190 years old.

On Saturday, when Philly celebrates the nation’s 250th birthday, the high may fall just short of 100, said Matt Benz, senior meteorologist with AccuWeather, as the high pressure “heat dome” covering much of the nation loses some of its protective power over Philly.

That also could be a window for “ring of fire” thunderstorms that could be nasty. The federal Storm Prediction Center sees a 15% chance that any storms on Saturday could become “severe,” with wind gusts up to 60 mph.

By Sunday, highs will be backing off to the 90s, however the sequence of warm nights probably will persist, at least in areas of Philadelphia most affected by the urban heat island effect.

The world has been getting warmer, but cities long ago got the jump on climate change, and their impacts on temperature were observed in the 19th century and documented in a famous experiment in the 1950s by legendary climatologist Helmut Landsberg.

Landsberg, who observed temperatures had fallen in some European cities after World War II bombings destroyed buildings, set up instrument arrays in an area of Maryland that was undergoing rapid development. As surfaces were paved and structures erected, he recorded significant localized temperature increases.

In Philly, dense neighborhoods can be several degrees warmer than other areas even within the city. Urban areas reduce cooling at night because they are efficient at storing the sun’s energy and slower to release heat after sunset.

The heat-death tolls in Paris in 2003, Chicago in 1995, and Philadelphia in 1993 underscored the urban heat hazards.

The city reported 113 heat-related deaths in the summer 1993, and no other summer has come close. In fact, a total of 42 were recorded in the 10-year period that ended last summer.

“We’ve been really lucky,” said Samuel Eldrich, medical director of the Temple Health-Chestnut Hill Hospital Emergency Department

The decline has a lot do with Philadelphia and that summer of 1993, Eldrich added.

That year, Philadelphia was under fire because it was the only major Eastern city reporting significant numbers of heat deaths. The medical examiner’s office was using forensic evidence, such as closed windows, in determining heat deaths.

The reasoning: With so many people dying, doctors wouldn’t be able to get to the bodies in time to verify core body temperatures of 105 degrees, the standard for hyperthermia. The Centers for Disease Control later decreed Philadelphia’s method was correct, and it was adopted elsewhere.

The dramatically high death toll was the impetus for the city’s emergency response plan, lauded by CDC and the National Oceanic and Atmospheric Administration that lauded as a national prototype.

It includes opening cooling centers and nudging residents to look in on older neighbors, and having the Philadelphia Corporation for the Aging operate a “heat line,” 215-765-9040. It will be operating daily from 8:30 a.m. to 8:30 p.m., and the agency “can also assist callers reporting concerns about vulnerable neighbors, family members, or community members,” said spokesperson Bill Conallen.

Citing Census figures, the Corporation for Aging says about 95,000 people 65 and older live alone in the city.

Subject to change, the heat wave is due to end Monday, with highs in the lower 80s (remember when that seemed hot?).

In the meantime the experts are offering coping tips, the three most-important being hydrate, hydrate, hydrate.

How much water should you drink? More than you think, said Schreyer. Men should drink about a gallon a day, women three quarts, but four to eight cups additional wouldn’t hurt. Sip, don’t guzzle, she said.

At a time when everyone wants to be outside, it’s critical to take breaks in air-conditioned stores, malls, or wherever, even for a few minutes, Eldrich said. “It gives your body a chance to recover,” he said.

Sunny G. Hallowell, associate professor of nursing at Villanova University, recommends cool showers and tepid baths. Also, especially with storms threatened, be prepared for power outages. She suggested storing damp towels in the refrigerator or freezer as a quick cool-down resource should the A/C go off.

She also recommends keeping a cool attitude. “This is temporary,” she said, and if the temperature hits a record, that’s “something to brag about.”

And if you’ve had it with the heat, think back to your misery during the Arctic freezes, and think that with the heat, “You got your wish.”