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Climate scientists say California had less than one percent chance of beating drought

Recovery could have taken decades

A depleted reservoir with parched earth and stunted trees.

California Governor Jerry Brown officially declared the drought over last Friday, a dramatic conclusion to years of dry weather capped off by two winters of violent storms.

Though drought damage will take years to undo, and another drought may even be around the corner, it was a remarkable turnaround.

In fact, according to the National Oceanic and Atmospheric Administration, it was the proverbial one in a hundred shot.

“The odds of the state completely recovering from its extreme dryness within two years are estimated at less than one percent,” paleoclimatologist Eugene R. Wahl, told NOAA.

Wahl and his colleagues published a paper this week in the peer-reviewed Journal of Climate comparing the present drought recovery to droughts past.

Folsom Lake in 2015.
Public Domain

In fact, that paper (given the scintillating title “Multi-century evaluation of recovery from strong precipitation deficits in California”) pegs the odds of this kind of recovery at closer to 0.5 percent.

Wahl and his comrades went all the way back to 1571 to contextualize the weather’s recent ups and downs.

“Full recovery to long-term average moisture delivery could typically take up to several decades in the hardest-hit areas,” according to the past examples.

The state’s precipitation maneuvering becomes even more remarkable when you note that it was uneven—Southern California didn’t get nearly as much love from El Nino, and a very small part of it is still in drought.

“Multi-century analysis suggests the north-wet/south-dry pattern for such an El Niño was a low-likelihood anomaly,” writes Wahl.

Shasta Lake. Note that this image is actually from an older dry spell in 2005.
Bob J Galindo

The researcher does hedge in comments to Wired that his study “only looks at dryness”—the actual lack of rain, rather than drought, a term which takes other environmental factors into consideration.

And he cautions NOAA that the state may not yet be in full recovery, and right now we’re simply “moving in a good way.”

Still, next time rain hits—which will be in a day or two, according to the most recent Bay Area forecasts—consider how remarkable the manifestation really is. And how hard it may be to get it back if we end up in another long dry spell in the future.