More than 100 million Americans were under some form of heat warning or advisory Tuesday as a withering, potentially record-breaking heat wave intensified across the central and eastern USA.
The heat moved east after scorching portions of the West late last week and over the weekend. Phoenix, Las Vegas and Denver were among cities posting record temperatures.
This cauldron of misery has been exacerbated by a sprawling heat dome that has wandered around the West this summer, sending temperatures skyrocketing. A heat dome occurs when the atmosphere traps hot air like a lid or cap.
What is a heat dome?
A heat dome is the result of a strong change in ocean temperatures from west to east in the tropical Pacific Ocean during the preceding winter, according to the National Ocean Service. The warm air coming from the west part of the Pacific Ocean gets trapped in the jet stream as it approaches land.
When that hot air arrives over land, the atmosphere traps it. Winds can move the heat dome around, so it is also referred to as a heat wave.
Western states face persistent drought conditions
Nearly 92 million people in the U.S. were affected by drought in June. Although drought in the west has improved slightly after dropping to a 20-year-low last summer and fall, more than 92% of the region remains in drought, according to the U.S. Drought Monitor.
Drought conditions: 2021 vs. 2022
Conditions continue to be hot and dry across the Southwest. In addition to parts of California, Nevada and Utah, exceptional drought has expanded to New Mexico and much of Texas.