Climate scientist says we’re not measuring the right things to predict drought

Even after recent rains and snow, the western United States is facing another year of extreme drought. Last week, Governor Kate Brown declared drought emergencies in four more Oregon counties, bringing the total to 11.

Water managers in Oregon and across the West will have to decide where scarce resources should go. But these water managers rely on outdated data, says Andrew Schwartz, who manages the Central Sierra Snow Laboratory for the University of California, Berkeley.

The dry bed of Lake Detroit is pictured in this file photo from October 25, 2015.

Courtney Sherwood

On the one hand, he says, climatologists need to spend more time observing the ground.

“When we have these prolonged droughts, our soil dries out a lot,” says Schwartz. “This means that any new rain or snow that arrives can be immediately absorbed by this ground and reduces the amount that enters our waterways and then our reservoirs.”

Schwartz says these dry soils also make wildfires more likely. This, in turn, reduces the canopy of trees that would have provided shade over the snow, which melts the snow faster and dries out the ground further.

An aerial view of the forest surrounding Jawbone Flats, where the Beachie Creek Fire has burned nearly 200,000 acres.

An aerial view of the forest surrounding Jawbone Flats, where the Beachie Creek Fire has burned nearly 200,000 acres.

Daniel Hurst/OPB

“All of these processes have existed in the past, but their year-to-year variability or year-to-year droughts have not been so extreme,” Schwartz says. Now, “we see gravity increasing with anthropogenic climate change.”

The consequence of this modeling can mean that water managers make the wrong decisions about where scarce resources go.

“If these models overestimate, for example, our water going into the reservoirs, we can release water that we don’t have the opportunity to waste,” says Schwartz. “So that could mean less water for ordinary people, less water in your taps – potentially even entire cities going dry.”

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