A heat wave that has buckled roads, disrupted mass transit and zapped power in scattered areas as weary New Yorkers crank up their air-conditioners delivered its biggest wallop so far Friday with a combination of heat and humidity that felt as hot as 109 degrees in some parts of the area.
An excessive heat warning was in effect for what forecasters said was the most dangerous day of the heat wave that began on Sunday and is expected to end Saturday, after seven days in a row with temperatures 90 or higher.
The warning means that fatigue, sunstroke, muscle cramps, heat exhaustion or heatstroke were possible for those who spend time outdoors. Anyone who works outside or must be in the elements was urged to take precautions, including wearing lightweight, loose-fitting clothing and drinking plenty of water.
The beach doesn't even offer a total escape -- doctors at a Jersey Shore facility say they have seen patients during this heat wave with feet burned by hot sand. A thermometer set on the beach at midday this week showed 120 degrees after less than three minutes.
"It feels like you're walking on fire, honestly," said Brandon DiMeglio, who rents out chairs to beachgoers.
The strain has already caused numerous scattered outages, including in Crown Heights Thursday.
"The air conditioner just went off," said resident Claude Abraham. "It just didn't work at all."
"It's too hot," said store owner Jamal Al-Onofi. "It's crazy in here, it feels like more than 100 degrees."
In Bergen County, at least 10,000 JCP&L customers were without power including residents of Tenafly, Saddle Brook and Wood-Ridge.
Con Edison said electricity usage reached an all-time high Friday with 13,214 megawatts at 2 p.m. in its service area, which encompasses New York City and Westchester County. That's up from 13,189 megawatts on July 22, 2011.
Residents in many tri-state areas are being asked to reduce electricity to take pressure off the state's power grid and help prevent failures. Consumers are being asked to set air conditioner thermostats no lower than 78 degrees and to turn off air-conditioning when they aren't home. They're also urged to turn off any unnecessary lights and use appliances only in early morning or late at night when overall demand is generally lower.
On Long Island, the extreme heat has even buckled roads, when the concrete expands and gets so tight for its space that it pops up. The state Department of Transportation reported two trouble spots in Suffolk County on Thursday, and crews were at both locations working to repair them. That's done by breaking up the concrete and adding a temporary patch.
The heat has also been blamed for mass transit snarls, after power lines sagged on Wednesday and disrupted rail service all along Amtrak's Northeast Corridor, which also affected New Jersey transit commuters. Long Island Rail Road has also contended with disruptions.
The high Friday is forecast at 98, and Saturday will be the final scorcher with a high of 92. Sunday brings relief with a high of 85.
--Ted Greenberg and Greg Cergol contributed to this story