DRI Data Shows Driest Spring on Record for California
Western Regional Climate Center records date back 114 years
RENO - Responding to data provided by the California Department of Water Resources and the Desert Research Institute, California Gov. Arnold Schwarzenegger today proclaimed drought and ordered immediate action to address dry conditions.
Data from the Western Regional Climate Center (WRCC) at DRI and California Department of Water Resources (DWR) indicate that the climatological spring season, March through May, has been the driest in 114 years of record in the state of California. Preliminary data from the California Climate Tracker (CCT, http://www.wrcc.dri.edu/monitor/cal-mon/index.html)shows that the total California statewide precipitation for spring 2008 was 1.21 inches, or 22 percent of the 1895-2007 average. In addition, DWR's 8-station index experienced its driest climatological spring in their 88 year record, with just 3.4 inches of precipitation for the months of March, April and May.
"At DRI, the Western Regional Climate Center has developed products to monitor climate in California, and in this case, the California Climate Tracker," said Laura Edwards, DRI Assistant Research Climatologist. "The WRCC serves as the archive for climate data in the Western United States."
The CCT at WRCC is updated monthly with the National Weather Service's Cooperative Observer Network (COOP) data. The current preliminary data will be quality checked, and aggregated with late reporting data and Parameter-elevation Regressions on Independent Slopes Model (PRISM) data from Oregon State University, to create the final product. The record is expected to hold when all data is finalized.
DWR's northern Sierra 8-station index has 34.8 inches for the water year so far, since October 1, 2007. This is 73 percent of normal for the index for this time of year, just slightly less than the 75 percent of normal that was recorded on this date last year. The 8-station index represents precipitation conditions for Northern California. Individually, the current 2008 water year ranks as the 22nd driest year in the 88 year period of record. Combined with 2007, the two-year total ranks as ninth driest.
Preliminary COOP data for individual stations have also established new records. For example, downtown Sacramento, whose record dates back to 1849, reported just 0.17 inches for the three month period, 0.38 inches less than the previous record set in 1934. San Francisco's total precipitation for March through May of this year was 0.47 inches, which is the driest spring in 159 years of record keeping. In southern California, Bakersfield tied its spring record with 0.08 inches, which last occurred in 1992. All 0.08 inches this spring fell in the month of May.
The winter of 2007-08 has been characterized as a La Nina season by National Oceanic and Atmospheric Administration, and may have been the strongest in 20 years. A climatological analysis shows that historically, springs following La Nina winters are typically 13 percent drier than average for California. Eleven of the 19 La Nina years since 1895 reported 80 percent or less of average spring precipitation across the state.