The deadly inferno that has baked the Upper Midwest and Plains states for a week is blowing its torch toward the East, where temperatures are expected to hit triple digits in the nation’s capital and other cities into the weekend.
The furnace, which TV weather forecasters have dubbed a “heat dome,” is blamed for nearly two dozen deaths and affects nearly 150 million people in the 32 states and Washington, D.C., where heat warnings have been issued. It has conjured memories of the 1995 heat wave, in which 700 people died of heat-related causes in Chicago alone.
"What makes this heat wave so impressive is the pure size and longevity," AccuWeather.com forecaster Mary Yoon said.
Some cities already have experienced temperatures in the 100s, and the combined heat and humidity could push the so-called “real feel” temperatures to 115 degrees through Saturday, the National Weather Service (NWS) said.
"Do not take this threat lightly," the NWS warned on its website, noting the extreme temperatures are particularly dangerous for the elderly and the very young. "The length of this heat wave will pose a very real and dangerous health risk to these at-risk groups and those that do not have access to air conditioning."
The temperatures have strained electrical grids in several states, and electricity utility Con Edison predicted scattered outages in New York when it expects demand to hit the all-time high in coming days.
In Chicago, the heat triggered unhealthy smog levels to the extent that the Illinois Environmental Protection Agency urged people to reduce polluting activities such as idling vehicles and mowing lawns.
Longstanding records in Philadelphia and other cities are expected to fall during temperature spikes on Friday. The low pressure system that barreled east was expected to bring powerful thunderstorms with hail to northeastern states.
The heat wave’s legacy of death stretches back to last week, when the first casualties were among tens of thousands of poultry and other livestock in several Midwestern states.
It then moved to human targets, and some stories were particularly tragic.
In Hutchinson, Kan., for example, three elderly people were found dead in separate homes on Wednesday. One of the victims was a 76-year-old man who had an air conditioner.
"He had an air-conditioning unit in the window but didn't use it because he didn't want to pay the electric bill," said Hutchinson Police Sergeant Thad Pickard.
The heat wave is old news in Texas and the southern Plains states. Oklahoma experienced its 30th day of triple-digit temperatures this year on Wednesday.
The heat dome has left people scrambling for ways to cool off, with crowds flocking to swimming pools and lakes.
Thursday morning, the promise of refreshing ocean breezes filled Boston's whale-watching ships and high-speed tourist boats sold out their trips by mid-morning.
Such respite is hard to find, because of the nature of the beastly heat.
"This is an exceptionally strong ridge of high pressure that really has an exceptional scope and duration," NWS meteorologist Eli Jacks told the BBC.
"The air is sinking,” he said. “As it sinks, it compresses and gets warmer."
It also dries out, so few clouds form to block the high early-summer sun, he said.
Exacerbating the problem in cities are asphalt and concrete pavement and buildings that "re-radiate" the heat, he said. "There's no good place to be."
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