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Why are heat waves around the world getting more intense?
03:28 - Source: CNN
CNN  — 

The deadly heat wave scorching much of the US will continue Sunday, when the Northeast and mid-South regions are likely to be suffocated by temperatures feeling as hot as 105 degrees.

More than 90 million people across the country are under various heat alerts for dangerously high temperatures. Sunday is expected to bring the hottest temperatures to the Northeast.

“From the southern Plains into the East, it will feel extremely oppressive, especially in the major metro areas of Washington D.C. to New York City and Boston,” the National Weather Service warned.

In New York City, at least one person died from heat exposure Saturday, a spokesperson for the city’s medical examiner’s office said. The person also had other medical issues, the spokesperson said. The forecast high in the city Saturday was 97 degrees.

Other heat-related deaths during this week’s heat wave include a 73-year-old man who was found Thursday in a room without air conditioning in Allentown, Pennsylvania, according to a medical examiner. He had several underlying medical conditions, including diabetes.

In Dallas, a 66-year-old Dallas woman who also had underlying health conditions died last week, according to county officials. And Wednesday, a 22-year-old hiker died due to possible dehydration and exposure after running out of water in a South Dakota national park, officials said.

Cities including Philadelphia, Boston and Washington, DC, are set to see heat in the upper 90s, with humidity intensifying conditions to feel as high as triple-digits.

The extreme conditions – which experts note are becoming more common around the globe due to climate change – have led local officials to issue heat emergencies to allow for resources to aid in confronting the heat millions have been enduring. Officials are also imploring people to practice extreme caution when spending time outdoors, stay hydrated and check on vulnerable communities and neighbors.

On Sunday, heat index values – what the air feels like – may exceed 100 degrees in some areas due to stifling humidity, the Weather Prediction Center noted.

“Widespread high temperature records are forecast to be tied or broken from the Mid-Atlantic up into New England (Sunday) with many places expected to hit the upper 90s and heat indices to eclipse 100 degrees,” the prediction center wrote.

Metro areas under heat emergencies Sunday as temps soar

Boston has been under a heat emergency warning since Tuesday, and with continued high heat in the forecast, Mayor Michelle Wu extended it through Monday. On Sunday afternoon, the temperature in the city hit 100 degrees, the highest it has been for the calendar day for 89 years.

The city has opened cooling centers, splash pads, indoor pools and public library locations for residents to seek relief from the heat.

The scorching heat wave caused a power outage Sunday for about 7,500 customers in the Dorchester neighborhood of Boston, power company Eversource told CNN in a statement. The company was able to restore power for about 12,500 customers earlier Sunday, they said.

In New York City, where a heat advisory is in effect until 8 p.m. Sunday, Con Edison workers were restoring “scattered outages caused by the scorching heat,” the electricity provider said. The company’s website showed about three dozen customers without power as of Sunday afternoon.

In Philadelphia, where the high is expected to be 99 degrees Sunday, officials extended a heat health emergency. Cooling centers, home visits by special teams and enhanced daytime outreach to people experiencing homelessness are available through the weekend.

“Very hot weather can make people sick, even healthy adults. During this heat wave, please be sure to check on neighbors and loved ones, especially the elderly,” Philadelphia Mayor Jim Kenney wrote on social media.

To the west, in Greensburg, Pennsylvania near Pittsburgh, more than 10,000 customers were still without power Sunday after storms a day earlier.

“With another round of storms potentially in the forecast later today, delays and additional outages are possible,” West Penn Power said. “As higher-than-normal temperatures are also impacting our service area today, customers should take any necessary steps to stay safe and escape the heat.”

In Washington, DC, where the mayor declared a heat emergency earlier this week, temperatures are expected to reach 100 degrees Sunday. The emergency will last through at least Monday morning, allowing for the availability of shelters and cooling centers to serve those who need them, Mayor Muriel Bowser said.

New York Gov. Kathy Hochul urged people in her state to take advantage of cooling centers and check on particularly vulnerable communities.

“We need everyone to be on alert this weekend, keeping an eye out for any signs of heat-related illness and looking after one another,” Hochul said in a news release.

People use an umbrella to shelter from the sun while looking at the Washington Monumnet in Washington, DC, Saturday

Excessive heat is the leading cause of weather-related deaths in US

In the US, excessive heat is the leading cause of weather-related deaths, and the conditions climate change imposes have been making extreme weather events more deadly and more common.

In fact, heat deaths have outpaced hurricane deaths by more than 15-to-1 over the past decade, according to data tracked by the National Weather Service.

Part of the problem is the high humidity making it feel like more than 100 degrees in many areas also makes it harder for the body to cool down.

“Sweating removes 22% of excess body heat by redirecting heat towards the evaporation of the sweat,” CNN meteorologist Robert Shackelford explained. “High humidity means that there is more moisture in the air. Since there is significantly more moisture in the air, it causes sweat to evaporate slower, which leads to a slowing down of your body’s natural ability to cool.

In Arizona’s Maricopa County, there have been 29 confirmed heat-related deaths since March, according to the county’s public health department. Last year, there were 16 heat-related deaths during the same period, the health department said. In the meantime, dozens of other deaths are under investigation in the county for heat-related causes.

New York City sees an average of 10 heat stress deaths every year, according to a report commissioned last year by the city’s health department. The report found a lack of home air conditioning “continues to be an important risk factor for heat stress death.”

It is not known whether the person who died of heat exposure Saturday had access to air conditioning.

CNN’s Isa Kaufman Geballe, Haley Brink, Allison Chinchar Rachel Ramirez, Liam Reilly Benjamin Schiller and Emily Chang contributed to this report.