Most major cities are now experiencing two more extreme heat streaks each year compared to 1970, according to an analysis by Climate Central, which found that human-caused climate change is driving the trend.
The nonpartisan research group defines an “extreme heat streak” as at least three days in a row where a city’s daily high temperature is hotter than 90% of all highs during the last few decades.
That’s happening even more frequently than the national average in several parts of the Mountain West. Denver and Colorado Springs have experienced four more extreme heat streaks than they did 50 years ago. Phoenix and Tucson, Ariz., Cheyenne, Wyo., Helena, Mont., and Las Cruces, N.M., have three more streaks.
Research shows that when extreme heat lingers, the risk of heat-related illnesses rise, particularly for children, pregnant people, and weather-exposed workers.
Demand for cooling also surges, putting pressure on power grids, said Sean McKenna, a scientist at the Desert Research Institute in Reno, Nev.
“Homes built in Reno, even in the ’70s, really didn't have air conditioning because we didn't need it. We had cool evenings. We could cool the house off,” McKenna said. “But if you look at a metro area now, like Las Vegas or Phoenix, you’ve got to run the air conditioner all night long just to stay cool.”
He said as energy-intensive cooling increases, so do the risks of power outages and blackouts, which can knock out air conditioners when needed most.
This story was produced by the Mountain West News Bureau, a collaboration between Wyoming Public Media, Nevada Public Radio, Boise State Public Radio in Idaho, KUNR in Nevada, KUNC in Colorado and KANW in New Mexico, with support from affiliate stations across the region. Funding for the Mountain West News Bureau is provided in part by the Corporation for Public Broadcasting.
