Daily Archives: June 24, 2015


California has been in drought for some time now, visible in California data for the Palmer Drought Severity Index, or PDSI. It’s a measure of, well, drought severity. On the PDSI scale negative numbers mean drought (i.e. unusually dry conditions) while positive numbers mean unusually wet conditions, so it’s the most extreme negative PDSI values that mark the most extreme drought. Anyway, here are 12-month moving averages of the data through April


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