The scorching spring heat dome that baked the West for well over a week has finally moved along, after setting more than 1,500 temperature records across 11 states, according to the research group Climate Central.In its wake, climate scientists, irrigation managers and local officials are taking stock of a looming water crisis and trying to make sense of just how exceptional the heat wave turned out to be. Even before the high temperatures arrived, Western states were reporting some of their weakest snowpack numbers in modern history. Now, in many places, little snow remains.Researchers have long recognized that climate change intensifies heat waves. But some scientists are wondering whether novel or little-understood climate dynamics could help explain the length, intensity and breadth of this month’s event.A Los Angeles Dodgers fan covers up to protect himself from the sun during a spring training game on March 21 in Phoenix. (Ross D. Franklin / AP)(Ross D. Franklin)Jennifer Brady, a senior data analyst at Climate Central, said the heat wave’s widespread footprint and duration made it an outlier “even with what we’re experiencing now with climate change and what a lot of people refer to as our new normal, or our new baseline.”AdvertisementAdvertisementThe organization developed a metric it calls the “Climate Shift Index,” which rates the influence of climate change on average daily temperatures from 1 to 5.About 29% of the country recorded maximum temperatures that Climate Central classified as a “5” — meaning they were at least five times as likely because of climate change. Based on data dating back to 1970, it was the highest-ever share of the U.S. landscape that experienced such temperature anomalies, the group found.“This is unprecedented and can be very dangerous,” Brady said.People flock to Baker Beach near the Golden Gate Bridge during a heat wave in San Francisco on March 16. (Tayfun Coskun / Anadolu via Getty Images)(Tayfun Coskun)The World Weather Attribution group — a consortium of scientists that presents statistical analyses quantifying how much climate change influenced a particular event — has said the earliest portion of the March heat wave was so statistically unlikely that it would be considered “virtually impossible” without climate change. Temperatures were 20 to 30 degrees Fahrenheit above average in some locations during that time.AdvertisementAdvertisementIn a report published on March 20, the group found that heat waves in the West h …
