For the second straight year, California has experienced unusually dry winter weather, leading desperate water agencies to try to make up for the shortfall using cloud seeding. By spraying fine particles of silver iodide into a cloud system, officials hope to cause water droplets in the clouds to form ice crystals and turn into snowflakes, increasing the annual amount of precipitation. While the practice has existed for decades, it has remained controversial due to doubts about its effectiveness and fears that it may cause extreme weather — both worries that experts say are unfounded based on the latest research.

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Image © theaucitron

In a recent report, the California Department of Water Resources estimated that cloud seeding projects generate an additional 400,000 acre-feet of water supply in the state each year. Considering that just one acre-foot is enough water to supply a typical household for a year, they consider the projects to be enormously cost-effective, especially compared to more costly measures like desalination, new dams, and conservation projects.

Over a dozen California watersheds have cloud seeding projects, many of which began operating last week. The state is going to need all the help it can get: so far, San Francisco has received only 3.95 inches of rainfall between November 7th and January 1st, the lowest level since record-keeping started 164 years ago.

Via Quest

Lead image © Karin Dalziel