Publication Date May 5, 2016 | Scientific American

Drought-ridden LA tries rainmakers to tap storm clouds

United States
L.A. and other municipalities have paid for flare trees, like these ones, to seed storm clouds with silver iodide in hopes of boosting rainfall. Photo: L.A. County Deprtment of Public Works
L.A. and other municipalities have paid for flare trees, like these ones, to seed storm clouds with silver iodide in hopes of boosting rainfall. Photo: L.A. County Deprtment of Public Works

Los Angeles has officially stopped trying to make it rain—for now. During three separate storms in the past two months, contract workers for the L.A. County Department of Public Works ignited 25 special flares in the hills above Pasadena, sending columns of glittering smoke into the clouds to give them a literal silver lining that could boost precipitation.

The efforts mark the first time since 2002 that the parched metropolis hasseeded clouds in an attempt to enhance rainfall; it is currently enduring a nearly five-year-long drought with this winter’s rainfall at just 40 percent of the usual amount