More than 30 million people in the Northeast and mid-Atlantic are still under heat alerts as record-breaking temperatures hit major cities like New York, Philadelphia and Washington, D.C.

The extreme heat has shattered multi-decade daily temperature records ahead of the Memorial Day weekend.

Here are some of the impacts and ripple effects of this intense heat.

Public Safety Alerts And Government Services

New York City officials declared a "Code Red" due to soaring temperatures into the 90s, forcing the city to open hundreds of public cooling centers so residents could escape the dangerous and potentially deadly heat.

Newark, New Jersey, similarly issued their own "Code Red" to coordinate emergency cooling resources, distribute water and protect vulnerable populations.

In Bethlehem Township, Pennsylvania, a devastating house fire erupted on Jodi Court during the peak of the heatwave. For the responding firefighters, this presented extremely grueling and exhausting conditions, as they had to battle both the flames and the outdoor heat. 

Power Grid Strain

Right when people need electrical services to power AC cooling systems the most is when power grids start to struggle. Heat makes it harder for power grids to perform well, while simultaneously, the demand for energy goes up.

With this heatwave, the strain has been be significant. 

As a way to curtail these potential effects, the U.S. Department of Energy declared a statutory emergency, granting the mid-Atlantic’s regional grid operator the authority to reduce power to large energy consumers, like data centers, to prevent a widespread blackout.

(MORE: Record Heat Fuels Severe Storms Across Northeast Wednesday)

The nation’s largest wholesale power market — which serves about 67 million people across 13 states and Washington — warned that power reserves are tight enough to cause concern, according to Politico.

When power systems fail, the consequences can be wide-reaching. And in some places, they are failing. More on that below.

Homes And Apartment Complexes Without AC

Residents in some northeast Philadelphia apartment buildings have reported “unbearable” living conditions due to broken air conditioning units during the peak of the heat.

And just over the northeast U.S. border in Ontario, a severe outage left nearly 13,000 customers temporarily without air conditioning and fans at the hottest time of the day. The power grids of Canada and the U.S. are deeply interconnected. In 2003, there was a massive blackout in the Northeast U.S., affecting power in eight states and part of Canada.

Power Outages At Hospitals

Some hospitals in the Northeast have been facing major challenges.

While this heat wave is coming through, Jefferson Methodist Hospital in South Philadelphia had to be completely evacuated and temporarily closed. It started with an external water source that caused flooding in the basement, knocking out the power and failing backup generators, which caused building temperatures to spike.

And Hoboken University Hospital in New Jersey faced a temporary crisis when its aging infrastructure's cooling system broke down as the heat index climbed up to 98 degrees.

Disruptions To Schools

Several schools are dismissing students early or going fully remote for the day because of the extreme heat.

In Pennsylvania, the School District of Philadelphia transitioned 57 area schools to fully virtual learning because the aging buildings lack adequate air conditioning required to safely handle the extreme indoor temperatures. 

Nearby in Lancaster County, an untimely, localized power outage compounded the climate stress in East Lampeter Township, forcing the Conestoga Valley School District to implement an emergency early dismissal across all of its campus buildings.

(MORE: Northeast Heat Wave Smashed May Record In Philadelphia, But Relief Is On The Way)

Dozens of school districts throughout North Jersey triggered emergency 1 p.m. dismissals to get children home before the hottest part of the day. 

A similar scene played out across Connecticut, where districts in New Haven and surrounding areas cut the school day short to rescue students from sweltering, unseasonable classroom environments.

Health Risks

World Health Organization officials warn that extreme heat can be extremely dangerous and even fatal.

Particularly for vulnerable populations like older adults and people with chronic health conditions, recognizing the early signs of heat exhaustion is critical.

Heat stress is a leading cause of weather-related deaths, and heatstroke specifically has a high fatality rate. Heat can also exacerbate underlying illnesses, including cardiovascular disease, diabetes and asthma.

Here are a few of our guides to make sure you know what you need to keep yourself and others safe during this heatwave.

• 5 Things You Should Know To Stay Safe During A Heat Wave
• Think A Quick Errand Is Safe? How Hot Cars Can Turn Deadly In Minutes
• Heat Can Turn Deadly Fast. Here’s What Your Body Is Trying To Tell You

A Developing Situation

This heatwave is finally dying down as relief is in view. Keep up with our meteorologist’s updates and find out when cool air will arrive here.

weather.com content writer Ada Wood enjoys exploring the stories that science and climate teach us about our natural world and how it influences the way we live in it.