Latest On California’s Drought: Total precipitation in past 12 months up slightly above average

By Paul Homewood

http://www.ncdc.noaa.gov/cag/time-series/us/4/0/pcp/12/9/1895-2016?base_prd=true&firstbaseyear=1895&lastbaseyear=2016&filter=true&filterType=binomial

Now that NOAA data for September has been published, we can look at Californian precipitation for the last hydrologic year, which runs Oct to Sep.

Total precipitation in the last 12 months ended up slightly above average. Prior to this, there was a run of four particularly dry years.

Maybe one reason why the recent dry spell has appeared to bee so pronounced is that the state had a number of unusually wet years in the 1980s and 90s.

But looking at the longer term trends, there have been similarly dry spells, notably in the 1920s and early 30s.

http://www.ncdc.noaa.gov/cag/time-series/us/4/0/pcp/12/9/1895-2016?base_prd=true&firstbaseyear=1899&lastbaseyear=2016

Reservoir levels across most of the state are either at or close to average.

http://cdec.water.ca.gov/cdecapp/resapp/getResGraphsMain.action

New Melones is the one which is significantly down. Yet, during the 1976/7 drought, it was effectively empty.

http://cdec.water.ca.gov/cdecapp/resapp/resDetailOrig.action?resid=NML

Statewide, reservoirs are 82% of the historical average, compared to 36% in 1977, based on September numbers.

http://cdec.water.ca.gov/cgi-progs/reservoirs/STORAGEW

California could certainly do with a couple of years of good rainfall, but things now appear to be manageable.