Millions of Americans brace for dangerous heatwave as ‘heat dome’ sends temperatures soaring

Approximately 70 million Americans are set to face excessive temperatures in the coming days as the third 'heat dome' to hit the US in just a matter of weeks hits the country.

A heat dome is 'created when an area of high pressure stays over the same area for days or even weeks, trapping very warm air underneath', according to the Royal Meteorological Society. Typically, it's described as 'a lid on a pot'.

Dangerously hot temperatures are now set to hit much of the US' southern and central states, with experts suggesting highs of between 95-105F are expected.

It's believed that the latest heat dome could break records in the Denver area over the weekend, as the National Weather Service warn temperatures could reach a toasty 108F.

Bob Oravec, meteorologist with the National Weather Service, said: "It looks like it is going to be pretty much stationary in that position as we go through the week."

Temperatures could reach as high as 108F (Kevin Carter/Getty Images)

The extreme heat is set to stretch from the Gulf of Mexico coast to the Great Plains and the midwest, and is set to cause disruption over the next week.

The worst pockets of heat are expected in Texas and parts of the Gulf Coast on Wednesday (July 29), according to weather experts.

Oravec said temperatures may drop in the US toward next weekend, though that will very much be a temporary relief, according to the meteorologist.

Children, the elderly, as well as those with medical conditions are most at risk from the heat dome, with experts warning those groups to stay out of the sun, especially during the hotter parts of the day.

How to stay safe in a heatwave

So, health experts say that's those most at risk should stay out of the heat if they can, but if they are required to be outside, they should avoid the hours of 11am and 3pm when the sun is at its hottest.

If the vulnerable are outdoors then, the NHS advises to stick to the shade.

More toasty temperatures are expected in the US over the coming days (Mario Tama/Getty Images)

People should also 'wear sunscreen, a hat and light clothes, and avoid exercise or activity that makes you hotter'.

The NHS states: ""Cool yourself down. Have cold food and regular cold drinks. Drink extra fluids but avoid alcohol, caffeine and hot drinks, and have a cool shower or put cool water on your skin or clothes.

"Keep your living space cool. Close windows, curtains and blinds during the day and open them at night when the temperature outside has gone down. Electric fans can help if the temperature is below 35 degrees."

The public is being urged to check on people in their community most at risk during this latest heat dome.