Millions of Americans are facing scorching temperatures as a record-breaking heat wave expands eastward, threatening major cities with particularly intense heat.

The relentless heat wave that has scorched the western US for the past week is now expanding into the central and eastern regions, bringing with it a slew of health risks and infrastructure challenges, according to USA Today.

As temperatures soar, meteorologists and health officials are sounding the alarm on the potentially deadly conditions facing millions of Americans.

A broad heatwave from the Plains to the East Coast will continue over the next couple of days, becoming particularly intense for many of the urban centers in the Southeast, Ohio Valley, and along the East Coast, USA Today reported, citing the National Weather Service.

At least 30 million people are expected to face temperatures of 100 degrees Fahrenheit (approximately 37.8 degrees Celsius) or higher, with millions more experiencing 90-degree Fahrenheit heat, according to AccuWeather.

The severity of the situation is underscored by the forecast of heat indices reaching 105 to 110 degrees Fahrenheit (approximately 40.6 to 43.3 degrees Celsius) in many areas. These extreme conditions are exacerbated by high humidity levels, creating a dangerous environment, especially for vulnerable populations.

These conditions will be dangerous and potentially deadly for those without adequate access to effective cooling and hydration, warned the weather service.

The risk is particularly high in urban areas across the Southeast, Ohio Valley, and East Coast, where the heat is expected to be most intense.

The heat wave has already been linked to at least 30 fatalities in the West, and concerns are growing as it expands eastward. Overnight temperatures, expected to remain in the mid to upper 70s, offer little respite from the daytime heat. (Anadolu Agency, excluding headline)