Drought During 2011 Has Caused Many Problems

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How severe has the California Drought been?

California statewide precipitation during the last three winters (November-April 2011/2012 through 2013/2014) ranked the second lowest since official measurements began in 1895. Merely the consecutive 3-year period of 1974/1975 through 1976/1977 was drier. As one critical indication of the cumulative and growing bear upon of this drought, the September 2014 assessment of statewide water storage was merely about 50% of average for this time of year, co-ordinate to the California Section of Water Resources. Water supply depletion has not resulted from the lack of precipitation alone, but also from very high temperatures with the 2013/2014 winter being the country’due south warmest on tape.

Equally the new 2014/2015 wet season commences, the current state of drought as assessed by the US Drought Monitor indicates almost all of California to be experiencing farthermost to infrequent drought severity. The state of affairs deteriorated greatly during the past year – the third consecutive twelvemonth of low atmospheric precipitation and the driest of the iii. Infrequent drought atmospheric condition cover over half of the state as of December 4, 2014, whereas i yr earlier no regions in the state were considered to exist nether exceptional drought conditions.

FIGURE 1: Three year average wintertime all-California precipitation for 1895/1896 to 2013/2014 from NOAA Climate Division Information.

Effigy two: Source: United States Drought Monitor: http://droughtmonitor.unl.edu

Us Drought Monitor: California
November 2011 – Present

Figure 3: Shown to a higher place are a video (meridian) and static fourth dimension series plot (bottom) depicting the development of the California drought. Start in November 2011, the progression of conditions from dry (xanthous/D0) to Farthermost (cerise/D3) and so Exceptional (dark red/D4) drought conditions can be seen across the country.

What factors caused the California Drought?

Weather condition conditions were key to explaining the issue – a high pressure ridge off the W Coast diverted the rails of storms during all three winters, typical of historical droughts.
Due west Coast high pressure level was rendered more likely during 2011-fourteen by effects of sea surface temperature patterns over the world oceans.
The drought’s first year (2011/2012) was likely the most predictable, when La Nina furnishings largely explained high pressure off the Due west Coast, though simulations point that high pressure connected to be favored due to ocean furnishings in 2012-fourteen.

Effigy four: The 200mb meridian (contours), sea surface temperature (color, ocean), and the U.S. precipitation (colour, land) anomalies for November 2011-Apr 2012 observed (summit) and boilerplate of 150 climate simulations (bottom). Red (bluish) denotes warm (cold), and brown (green) denotes dry (wet).

Is the California Drought a symptom of long term climate change?

The electric current drought is not function of a long-term change in California precipitation, which exhibits no appreciable trend since 1895. Key oceanic features that acquired precipitation inhibiting atmospheric ridging off the W Declension during 2011-14 were symptomatic of natural internal atmosphere-sea variability.

Model simulations indicate that man-induced climate change increases California atmospheric precipitation in mid-winter, with a depression-pressure level circulation bibelot over the N Pacific, contrary to conditions of the last 3 winters. The same model simulations indicate a decrease in spring precipitation over California. However, precipitation deficits observed during the by three years are an order of magnitude greater than the model simulated changes related to man-induced forcing. Nevertheless, record setting high temperature that accompanied this contempo drought was likely made more than farthermost due to human being-induced global warming.

Assessment Study Details

Causes and Predictability of the 2011 to 2014 California Drought

Dec 2014

Composed by the Narrative Team of the NOAA Drought Task Force

Atomic number 82 Author: R. Seager

Co-Authors: M. Hoerling, Southward. Schubert, H. Wang, B. Lyon, A. Kumar, J. Nakamura, Due north. Henderson

The NOAA Drought Task Force is organized by the Modeling, Assay, Predictions and Projections (MAPP) Program of OAR/Climate Plan Office.

Media Coverage

On Monday, Dec 8, 2014, NOAA held a scientific discipline briefing for the media to announce the findings of this study. Media in attendance during the teleconference included TIME, NY Times, NBC, United states Today, Washington Post, Huffington Mail, AP, Slate and Bakersfield Examiner, amongst many other news sources. Richard Seager, report pb author & professor, Columbia Academy’s Lamont Doherty Earth Observatory and Marty Hoerling, study co-author & researcher, NOAA’s Earth System Inquiry Laboratory, were bachelor to field questions from the media.