A sprawling heat dome is currently subjecting over 50 million Americans in seven southern US states to dangerously high temperatures, with some areas forecast to exceed 110 degrees Fahrenheit.
The National Weather Service (NWS) has issued extreme heat warnings and heat advisories for residents in Arizona, Arkansas, California, Louisiana, New Mexico, Oklahoma, and Texas. The oppressive weather system is expected to persist for days, posing a significant risk of heat exhaustion and heat stroke.
Texas is anticipated to bear the brunt of the heat, with major cities like Dallas, Fort Worth, Houston, San Antonio, and Austin facing extreme heat conditions. The NWS has categorized the conditions in Texas on Monday as 'major' or 'extreme' on its five-stage heat risk guidance chart, with 'extreme' indicating a lack of overnight relief and severe risks for those without air conditioning or adequate hydration.
Phoenix and Tucson in Arizona, along with San Diego and Los Angeles in California, are also under warnings. In Arizona, the life-threatening conditions are expected to last until Saturday night, with afternoon temperatures in the Phoenix area predicted to reach between 106 and 118 degrees Fahrenheit. Forecast highs in Phoenix for Tuesday and Wednesday are expected to challenge or break single-day records set in 2011.
California's heat warnings are set to remain in effect until Wednesday, with temperatures in Southern California expected to surpass 100 degrees throughout the week.
The NWS advises residents to drink plenty of fluids, stay in air-conditioned spaces, avoid direct sun exposure, and check on vulnerable relatives and neighbors. They also issued a stern warning against leaving children and pets in unattended vehicles, as interior temperatures can become lethal within minutes.
This phenomenon is attributed to heat domes, weather patterns where high pressure traps hot air and humidity, preventing atmospheric dispersal. Multiple heat domes have formed across the US this year, beginning earlier than usual in mid-March.
For those who must be outdoors, officials recommend lightweight and loose-fitting clothing and limiting strenuous activities to cooler morning or evening hours. The elderly, pregnant women, infants, young children, and individuals with chronic health conditions are identified as being at the highest risk for heat-related illnesses.
Symptoms of heat exhaustion include heavy sweating, fatigue, cool clammy skin, a fast weak pulse, muscle cramps, dizziness, nausea, and headaches. Heat stroke, a more severe and potentially fatal condition that can develop rapidly, may present with a throbbing headache, confusion, slurred speech, nausea, dizziness, and a fever above 103 degrees Fahrenheit. Affected individuals might also experience red, dry or damp skin, a rapid pulse, and loss of consciousness as their organs begin to fail.
The extreme heat is expected to worsen an existing severe drought in the Southwest, potentially leading to water shortages. Northern Texas, western Oklahoma, and parts of New Mexico are currently experiencing drought conditions classified as 'exceptional drought' (D4) by the US Drought Monitor. Large areas of Colorado, Idaho, and Oregon are also under this severe drought classification, increasing the risk of wildfires across the western US.