Swaths of the US are set to bake in 'dangerously hot' conditions of up to 118 degrees, the National Weather Service has warned.
An intense heatwave is due to sweep across the country starting today, sparking fears of yet more heat-related deaths and illnesses.
The NWS and the the Centers for Disease Control and Prevention has produced an alarming map showing the impact of the high temperatures across the lower 48 contiguous states over the next week.
It shows huge parts of Washington state, southern Louisiana, Mississippi, and Alabama, as well as small areas of Virginia, Massachusetts, New Hampshire, New Mexico, and Texas face an 'extreme' heat risk.
The East Coast, Gulf Coast, Northwest and Great Plains states are experiencing 'major' heat risks.
Swathes of the US are set to bake in 'dangerously hot' conditions of up to 118 degrees, the National Weather Service has warned
As the week progresses the major risk for the East Coast will dissipate, but heat is due to ramp up across California and Arizona.
Yellow areas on the map denote a minor risk, orange is moderate, red is major and purple areas face extreme heat risks.
The red and purple areas are due to move southeast throughout the week, weakening as they cross Colorado, Nebraska and Kansas before heating up again over Oklahoma, Texas, Arkansas, Louisiana and Mississippi.
'There is a high risk for dangerous heat illness for anyone, especially for the very young, the very old, those without air conditioning, and those active outdoors,' the NWS cautioned.
The NWS combines weather, climate and CDC data to determine the severity of the impact of heat.
The warnings come after scores of heat-related deaths across the country, including that of four-month-old Tanna Rae Wroblewski.
An intense heatwave is due to sweep across the country starting today, sparking fears of yet more heat-related deaths and illnesses
As the week progresses the major risk for the East Coast will dissipate, but heat is due to ramp up across California and Arizona
The baby is thought to have died of heat exhaustion, after her parents took her out boating on an Arizona lake amid a 120-degree extreme heat warning. Detectives are now probing the death.
A six-year-old Florida girl also died after she was left 'locked mom's boyfriend's sweltering hot car' while he was at work.
Nine-year-old Cortinez Logan also perished on a trail walk with his family at the South Mountain Park and Preserve near Phoenix as temperatures soared to 113F last month.
'Drink plenty of fluids, stay in an air-conditioned room, stay out of the sun, and check up on relatives and neighbors,' The NWS advised.
'Do not leave young children and pets in unattended vehicles. Car interiors will reach lethal temperatures in a matter of minutes.'
Meanwhile, firefighters battling California´s largest wildfire of the year are preparing for treacherous conditions entering the weekend.
Detectives are probing the parents of a baby girl who died after they took her boating on an Arizona lake during 120-degree heat
A helicopter drops water on the Park Fire near Butte Meadows, California, on Tuesday
The Park Fire, which has destroyed at least 480 structures and damaged 47, is one of almost 100 large fires burning across the western U.S.
Expected thunderstorms may unleash fire-starting lightning and erratic winds that could erode progress made over the past week.
Dry, hot conditions posed similar threats across the fire-stricken West.