Much of the country is experiencing a potentially dangerous heat wave as the nation prepares for a very special Fourth of July, marking the 250th anniversary of the United States. 

Over 160 million people, according to the New York Times, from Missouri to Maine and south to Mississippi, live in locations that felt dangerous levels of heat on Thursday, citing the National Weather Service. There were “heat risk” forecasts in major cities, including New York, Washington, Philadelphia, Pittsburgh and Atlanta, with some facing the most extreme risk category through Saturday.

CNN is reporting that “A dangerous heat wave is tightening its grip on the East Coast and straining the electric grid as people seek to cool off in their air conditioned homes and businesses. The worst conditions are now underway, with many records already broken, as millions prepare to celebrate the Fourth of July outdoors.”

The Times reported that the temperature in Central Park reached 100 degrees by 2 p.m., tying its daily record set in 1966. “LaGuardia​ Airport in Queens hit 104, surpassing its daily high of 101 from 1966. It was the same story at John F. Kennedy International Airport, where the high was 102, breaking the same-day record of 101, also from 1966.”