At least 25 deaths linked to US Independence Day heatwave as dangerous conditions persist

A prolonged and intense heat wave that gripped much of the United States over the Independence Day holiday weekend has been linked to at least 25 deaths, with officials warning that the full toll may rise as investigations continue.

The deadly conditions unfolded as a powerful "heat dome" settled over large parts of the central and eastern United States, pushing temperatures above 38°C (100°F) in more than 20 states and exposing millions of Americans to dangerous levels of heat.

According to US weather authorities, more than 140 million people remained under heat alerts on Sunday, as forecasters warned that heat-related illnesses and fatalities could continue even as temperatures begin to ease in some regions.

New Jersey reports the highest number of suspected heat-related deaths

The state of New Jersey has recorded the largest number of suspected heat-related fatalities.

State officials said at least 25 people are believed to have died as a result of the extreme temperatures, although final causes of death remain under investigation by medical examiners.

New Jersey Health Commissioner Dr Raynard Washington said many of the victims were discovered in homes without air conditioning, while others were found outdoors, on streets and inside parked vehicles.

Authorities reported that the deaths began occurring as early as Thursday, with most concentrated in central and northern parts of the state.

The victims ranged in age from their 30s to their 80s.

Officials said preliminary findings strongly suggest heat was a contributing factor in many of the deaths, though formal determinations are still pending.

"This is not a typical summer heatwave," the New Jersey Department of Health said in a statement.

"This type of heat can quickly become life-threatening to humans and to animals of all ages."

New Jersey Governor Mikie Sherrill described the event as one of the most severe periods of heat experienced by the state in more than a decade.

"Extreme heat is the number one weather-related killer in America, and this is the hottest stretch we've seen in over 14 years," she said.

Additional fatalities reported in Illinois and Mississippi

Elsewhere in the United States, officials reported several additional deaths linked to the extreme weather.

In Illinois, authorities confirmed at least one heat-related death in Cook County. According to local officials, the victim died from cardiovascular disease with heat stress identified as a contributing factor.

Another weather-related fatality occurred in Kendall County, Illinois, when strong winds toppled a tree onto a camper trailer at a recreational vehicle park, killing a 47-year-old woman inside.

In Mississippi, officials reported the death of 74-year-old Mitchell Ray Cooley, whose body was discovered behind a petrol station after he had been reported missing.

Investigators concluded that heat exposure was the cause of death.

According to the Hinds County Coroner's Office, Cooley suffered from a medical condition that impaired his judgement and may have contributed to his vulnerability during the extreme weather.

The state also recorded another tragic death linked to the heat.

Eighty-three-year-old Martha Irene Van Egmond died after falling in her garden in Bolton, Mississippi, during the height of the heatwave.

Her husband, Rick Van Egmond, also fell while attempting to help her. The couple remained stranded outdoors for hours in the oppressive heat before assistance arrived.

Local investigators later determined that a combination of heat exposure and advanced age contributed to Martha Van Egmond's death.

Record temperatures disrupt holiday celebrations

The extreme heat coincided with celebrations marking the United States' 250th year of independence, resulting in widespread disruptions to outdoor events across the country.

Several major cities along the East Coast recorded their hottest Independence Day temperatures on record.

Preliminary meteorological data showed Atlantic City, New Jersey, reached 41.1°C (106°F), making it one of the hottest locations in the eastern United States during the holiday weekend.

Washington, D.C., and Raleigh, North Carolina, both reached 39.4°C (103°F).

Baltimore, Wilmington and Salisbury climbed to 38.9°C (102°F), while Charlotte, Norfolk and Fayetteville exceeded 37.8°C (100°F), setting new daily temperature records.

Richmond, Virginia, matched a longstanding record by reaching 37.8°C, while Roanoke and Greensboro also tied previous highs.

The scorching conditions affected public gatherings and outdoor festivities, particularly in the US capital.

Ahead of a Fourth of July speech by President Donald Trump, authorities evacuated the National Mall due to severe thunderstorms and lightning approaching the area.

Visitors were directed into nearby government buildings before celebrations resumed later in the evening.

Severe storms follow the heat

The intense heat was followed by powerful thunderstorms that swept across parts of the Midwest, Plains and eastern United States.

Meteorologists recorded more than 500 incidents of wind damage across multiple states during the holiday weekend.

Strong winds reportedly reached speeds of up to 129 kilometres per hour (80 mph) in parts of New Jersey, knocking down trees and power lines.

Nearly 300,000 electricity customers in the state lost power during the storms.

Forecasters warned that additional severe weather, including flash flooding, damaging winds, hail and frequent lightning, remained possible across parts of the Mid-Atlantic region.

Cities including Washington, Baltimore and Philadelphia were identified as being at elevated risk of severe thunderstorms on Sunday.

Heat alerts remain in effect for millions

Although cooler air has begun moving into parts of the northeastern United States, much of the South continues to experience dangerous heat and humidity.

Heat advisories remained in force from Florida northwards to Pennsylvania, with "feels-like" temperatures forecast to exceed 38°C in many areas.

Cities including Jacksonville, Macon and Pine Bluff remained under active heat warnings.

The US National Weather Service said temperatures across the Northeast were expected to moderate significantly, with New York City forecast to fall into the upper 20s Celsius and Boston expected to experience temperatures closer to seasonal norms.

However, officials cautioned that heat-related risks remain elevated even after peak temperatures begin to decline.

Climate concerns intensify

The latest heatwave has renewed concerns about the growing frequency and intensity of extreme weather events in the United States.

Scientists have repeatedly warned that climate change is increasing the likelihood of longer-lasting and more severe heatwaves, particularly in densely populated urban areas where concrete and asphalt trap heat.

Public health experts note that extreme heat consistently causes more deaths in the United States than hurricanes, floods or tornadoes, yet often receives less public attention.

With much of the summer still ahead, emergency authorities across the country are urging residents to remain hydrated, seek air-conditioned shelter and regularly check on elderly relatives, neighbours and other vulnerable individuals.