Heavy precipitation is erasing years of extremely dry conditions in parts of California, with the latest federal report showing that just over 51 percent of the state remains in drought — and no areas have the worst rating, "exceptional drought."

It's the first time since January of 2014 that no part of California was in the exceptional drought category, according to the U.S. Drought Monitor report from weather and agriculture experts. In January of 2016, more than 40 percent of the state had that unwelcome distinction.

Currently, nearly 39 percent of California is also free of the more benign "abnormally dry" status — which, one year ago, covered the entire state. The change wrought by heavy rains is striking, as seen in a series of side-by-side photos of key reservoirs complied by member station KQED.

Drought conditions persist mainly in the south, affecting nearly 25 million people, according to the drought monitor. And Dan Cayan, a climate researcher at Scripps Institution of Oceanography in La Jolla, tells KQED that while some areas have already received a winter's worth of water, the risk of drought shouldn't be discounted.

"I'm a little reluctant to say the drought's over, even though conditions have markedly improved," says Cayan, citing the need to replenish groundwater aquifers.

Relief from the drought has come at a cost, as powerful and drenching storms also brought flooding, mudslides and damage — including to the iconic "Pioneer Cabin Tree," the sequoia that was carved into a tunnel in Calaveras Big Trees State Park.

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