(CNN) -- People in the northeastern United States were heading to waterparks and pools to try to cool off as a record-breaking heat wave continued to roast much of the region Wednesday, with temperatures hitting above the 100-degree mark in many cities, the National Weather Service said.
The weather service has issued an "excessive heat warning" until 8 p.m. Wednesday for parts of eastern Pennsylvania and parts of Delaware and New Jersey. The warning covers cities that include Philadelphia, Pennsylvania; Wilmington, Delaware and Trenton, New Jersey.
Officials advise people to stay indoors as prolonged heat and humidity creates a "dangerous situation".
The heat already has claimed the life of an elderly woman in Philadelphia, where temperatures hit 102 degrees Tuesday.
And young, fit people have succumbed to the extreme temperatures, too. Four midshipmen at the U.S. Naval Academy in Annapolis, Maryland, were being treated for signs of heat exhaustion Wednesday morning, according to academy spokeswoman Judy Campbell.
The temperature topped the 100-degree mark in Boston, Massachusetts; Washington DC, and New York, where it hit 103 Tuesday.
Amidst the oppressive heat, as many as 9,000 customers of Connecticut Light and Power in Stamford lost electrical service Tuesday. A heat-related transformer failure at a substation in Stamford caused the outage, said a spokeswoman for the power company.
By Wednesday morning, about 1,170 customers in Connecticut, 9,246 customers in New York state, 1,696 in Massachusetts and 8,300 customers in New Jersey were still without power. Power providers in Pennsylvania and other New England states were reporting very sparse and scattered outages, generally under 100 in each state.
Michael Clendenin of Con Edison told CNN's American Morning Wednesday that his company has been able to keep the power on for all but 6,000 or so of its 3.2 million customers in New York City.
"It is the kind of thing we expect in heat waves like this and we are working very hard to try to minimize the impact." Clendenin said.
He warned that the situation is far from over.
"So far, I would say we dodged major bullets. I think there's still a big shoot-out going on". Clendenin said.
Power isn't the only thing in sporadic supply in the heat-afflicted region. According to the general manager of the White Oak Ice company in Bensalem, Pennsylvania, "The whole tri-state area is just about out of ice -- New Jersey, Philadelphia and Delaware. Absolutely unbelievable. It's terrible up here. We haven't experienced this in 12 years, 13 years," said John Sylvester.
"All the big major companies are out of ice. Guys are scrambling. They're calling for ice and it's coming from Wisconsin, Ohio, the Carolinas and they're running out. Demand is way higher than what everyone can produce and I don't see any end in sight," Sylvester added.
"Other ice companies are calling us begging for ice. There's only a certain amount of guys who manufacture and a company like ours, we're keeping up with it but we're coming to an end. We've used all our ice in storage. We start storing in February or March. We make a couple hundred tons a day".
In New York, the city set up as many as 400 cooling stations in its five boroughs, according to the Office of Emergency Management.
Emergency Management Commissioner Joe Bruno urged people to use the center, and advised neighbors to check on neighbors to make sure they are well.
Some of those neighbors might not have air conditioning to begin with.
New Yorker Alfred Roblero not only lacks air conditioning in his apartment, he has to walk up six flights of stairs to get there.
"It's terrible. Most of the time my heart is like beating like... like I need air because of the heat," Roblero told CNN's Jason Carroll.
"This is a significant health emergency as well as a heat emergency," Bruno said.
In Middletown, Connecticut, police issued summonses for second-degree reckless endangerment to two high school football coaches who held practice in the heat, leading one student to collapse.
The assistant football coaches at Middletown High School staged a "strength and conditioning session that consisted of weight training and running" from 6 p.m. to 8 p.m. Tuesday, the Middletown police said.
A student passed out during a phase of the running that involved "sprinting up a hill several times," police said.
In Nashua, New Hampshire, Ben Dionne spent part of Tuesday outside cleaning out a pool. He told CNN affiliate WMUR he was following experts' advice to stay hydrated. "It's hot. I'm just trying to stay cool and get as much water as I can".
In Philadelphia, a 92-year-old woman was found dead in her home. The woman, who was discovered by a neighbor, had opened a few windows but did not have air conditioning, said a medical examiner's spokesman.
The National Weather Service is urging people to protect themselves.
"Be sure to check on your elderly relatives and neighbors. Coaches, trainers, camp counselors should remain alert for signs of heat exhaustion and heat stroke," the weather service warned.
The heat can also adversely affect animals, and that's having an impact on a popular New York City tourist attraction. The city's health department bans carriage operators from working their horses "whenever the air temperature is 90 degrees Fahrenheit or above," said department spokeswoman Suzanne Craig. She said anyone offering horse-drawn carriage rides at those dangerous temperatures is subject to fines from both the health department and the American Society for the Prevention of Cruelty to Animals, or ASPCA.
ASPCA officers in Central Park told Craig that operators complied with the mandate Tuesday, sidelining their businesses in the heat, except for early in the morning and late at night when temperatures dipped below 90 degrees, she said.
Some people are fleeing the city for cooler places nearby. Mountain Creek Waterpark in Vernon, New Jersey, is drawing a lot of New Yorkers, park spokeswoman Alice Heinrich said Wednesday. "It has been one of those weeks where everyone gets the idea, they see a heat wave and don't have pools, so they come out to the waterpark".
Heinrich said the waterpark is reminding visitors via its loudspeakers to drink fluids -- and making it easier for them to do so. Waterpark workers are going around handing out water to people waiting in long lines for rides, she said.
