Just how bad was California's last drought?
For most of Southern California, it was either the worst or second worst since the century Columbus landed in the New World, the Ottoman empire was started and Joan of Arc was burned at the stake.
In other words, it was one of the worst since the 1400s, according to a study released Monday by the California Department of Water Resources.
Compiled by examining trees in the southern half of the state, the study put the just-ended drought in some historical perspective. It was conducted in cooperation with the University of Arizona's Laboratory of Tree-Ring Research, which looked at trees in 46 different sites from the southern Sierra Nevada to just north of the Mexico border.
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The research revealed two nine-year droughts in California history: one starting in 1452 and another beginning in 1775. The most recent drought was relatively compact, lasting just five years, but appears to have set records for dryness, said Dave Meko, an Arizona professor who led the tree-ring analysis.
"If you look at five-year droughts ... that stands out as the most severe on record," Meko said in an interview Tuesday.
The study largely dovetails with previous estimates that the latest drought, which was declared over last spring by Gov. Jerry Brown, was among the worst ever. At one point in 2015, the Sierra Nevada snowpack was the thinnest it has been in 500 years.
Meko said the study also provided further evidence that year-to-year variations in rain and snow totals are becoming more pronounced in recent times. Last winter's record rainfall in Northern California, which broke the drought, has been followed by an unusually dry winter this year.
State officials have seized on that point in their efforts to preach water conservation even in wet years.
DWR Director Karla Nemeth, in a prepared statement, said the study confirms "what we've long believed and said. The norm for California's climate is to move back and forth frequently between wet and dry conditions, and water conservation must be a way of life."
Generally speaking, the last drought was more severe in Southern California than in the north state.
DWR's report comes at a crucial moment in California's current "water year." A fresh series of storms hitting the state this week could dump as much as 100 inches of snow on the Sierra Nevada, according to the National Weather Service. Sacramento is expected to get 2 to 3 inches of rain.
That raises some hopes of a "March miracle" that could bring precipitation to normal or near-normal levels after weeks of dry weather, although most experts say they believe the state will fall short.
Heading into this week's storms, the Sierra snowpack is just 36 percent of average. DWR's eight-station index, which measures a mix of rain and snow in the Sacramento Valley, is at 63 percent of average.