From Phoenix to Boise, high temperature records fell like dominoes over the weekend as an impressive heat wave engulfed the western U.S., helping to fuel several wildfires.
While heat waves are a regular part of summer weather, the steady warming of the planet means those heat waves are getting ever hotter, making record heat more and more likely.
The heat came courtesy of a ridge of high pressure that moved in over the West, with the peak temperatures, including several records, occurring on Friday and Saturday:
- Las Vegas hit 116°F on Friday, besting the record set in 1989 of 114°F. The city had a record-long streak of 23 days with highs above 105°F.
- On Saturday, Reno, Nev., bested its old record of 99°F with a temperature of 104°F.
- Los Angeles broke a record that had stood for 131 years, with the temperature downtown hitting 98°F (the old record was 95°F).
Extreme heat is one of the hallmarks of global warming; as the average temperature of the planet rises, record heat becomes much more likely than record cold. And cities in the Southwest — where most of the region’s population lives — are some of the fastest-warming in the country.
While no formal attribution study has been conducted to see how much more likely a heat wave like this has become with warming, a recent study found that heat records were made both more likely and more severe for about 80 percent of the area of the globe that had good enough observational data.