Climate change makes drought recovery tougher in U.S. West

SACRAMENTO, Calif. (AP) — Californians rejoiced this week when big drops of water started falling from the sky for the first time in any measurable way since the spring, an annual soaking that heralds the start of the rainy season following some of the hottest and driest months on record.

But as the rain was beginning to fall on Tuesday night, Gov. Gavin Newsom did a curious thing: He issued a statewide drought emergency and gave regulators permission to enact mandatory statewide water restrictions if they choose.

Newsom's order might seem jarring, especially as forecasters predict up to 7 inches (18 centimeters) of rain could fall on parts of the Northern California mountains and Central Valley this week. But experts say it makes sense if you think of drought as something caused not by the weather, but by climate change.

For decades, California has relied on rain and snow in the winter to fill the state's major rivers and streams in the spring, which then feed a massive system of lakes that store water for drinking, farming and energy production. But that annual runoff from the mountains is getting smaller, mostly because it's getting hotter and drier, not just because it's raining less.

In the spring, California's snowpack in the Sierra Nevada mountains was 60% of its historical average. But the amount of water that made it to the reservoirs was similar to 2015, when the snowpack was just 5% of its historical average. Nearly all of the water state officials had expected to get this year either evaporated into the hotter air or was absorbed into the drier soil.

“You don’t get into the type of drought that we're seeing in the American West right now just from ... missing a few storms,” said Justin Mankin, a geography professor at Dartmouth College and co-lead of the Drought Task Force at the National Oceanic and...