Temperatures in Phoenix, Arizona are expected to reach 120 degrees Fahrenheit (48.8 degrees Celsius) from Sunday, June 19, through Wednesday, June 22.
Since temperature monitoring began in the area in 1990, this would only be the fourth time the Southwest U.S. will experience this high heat.
According to the U.S. National Weather Service warning, the heat wave is "rare, dangerous and deadly." On Sunday, Phoenix temperature is predicted to reach 118 degrees Fahrenheit (47.7 degrees Celsius) and peak at 119 degrees Fahrenheit (48.3 degrees Celsius) on Monday, June 20.
"This is extreme even for our standards," said Phoenix-based weather service meteorologist Matthew Hirsch.
Temperatures in the Death Valley are expected to go up to 48.8 degrees Celsius, enabling the desert valley to live up to its name as the hottest area in the United States. The Coachella Valley in California, as well as areas in Los Angeles and San Diego counties, are also expected to experience the similar heat waves.
The Pacific Ocean's cool waters typically protect Los Angeles from the heat, but come next week, the temperatures could hit 100 degrees Fahrenheit (37.7 degrees Celsius).
Aircraft components are highly susceptible to high temperatures. This means that the incoming heat waves in Tucson, Phoenix and other areas in Arizona and Nevada can lead to flight cancellations. The highest temperatures are expected to occur on Sunday, Monday and Tuesday next week in Las Vegas and Phoenix.
To date, the highest temperature ever recorded in Phoenix was 122 degrees Fahrenheit (50 degrees Celsius), which occurred on June 26, 1990.
"We should anticipate more and more of this extreme heat, and we're getting to feel it firsthand. It is what global warming looks and feels like," said climate scientist Jonathan Overpeck from the University of Arizona.
High Heat Is Coming
Health experts said that a few degrees difference in outside temperature can lead the body temperature to rise as well. This spike can affect not just the brain but also the body's organs.
Infants, senior adults and persons suffering from health issues are highly vulnerable to the heat waves due to their inability to cool down fast enough.
Health experts advise people to keep a look out for heat stroke and heat exhaustion symptoms.
Heat stroke symptoms include rapid pulse, high body temperature, flushed dry skin and absence of sweat, breathing difficulties, agitation, disorientation, seizure and even coma. If heat stroke is left untreated, it can lead to disabilities and in some cases, death.