As heat wave ends in the West, scientists try to make sense of its intensity

The spring heat wave that baked the West for over a week has finally moved along, after setting more than 1,500 temperature records across 11 states.

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 / APJennifer 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.”

The 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.