Christopher C. Burt is the author of 'Extreme Weather; A Guide and Record Book'. He studied meteorology at the Univ. of Wisconsin-Madison.
By: Christopher C. Burt , 7:36 PM GMT on May 02, 2014
California Drought Update-May 2014
The water season (July 1-June 30) has, for all practical purposes, come to an end for California. Although May and June may see some additional precipitation (especially in the far north) it is unlikely that anything will happen to improve the prospect of a catastrophic drought this year for the state. Here is a monthly update.
The final snow survey in the Sierra Nevada was taken on May 1st and the statewide snowpack was just 18% of average for the date. This compares to 32% as of April 1st. The situation in the northern section of the survey area was just 7% of normal. This is the 2nd lowest snowpack figure for May 1st (May 1, 1977 being the lowest on record).
Snow-water content of the Sierra snow pack for each region compared to average (blue shaded area), maximum on record (purple line), lowest on record (red line) and this year (deep blue line). California Department of Water Resources.
Although April rainfall was close to normal for most of the state, the snow that fell in the Sierra melted quickly following each storm due to the warm April sunshine. The California Department of water resources has set this year’s water allocation at 5% of requested amounts (requested by agricultural and other public water agencies). This is the smallest such allocation in the 54-year history of the State Water Project operated by the Department of Water Resources.
Above is a chart of SWP (State Water Project) allocations since 1999. Not shown is the 5% allocation set for 2014, the lowest on record (for the past 54 years). Graph from California Department of Water Resources.
The state’s reservoirs are at critically low levels for this time of the year.
State reservoir capacities as of May 1st. Overall, the total capacity of all the water in all the reservoirs is currently about 50% of normal for this time of year. California Department of Water Resources.
So far as actual drought conditions and precipitation amounts as of May 1st, the latest drought monitor report (below) shows that there has been further deterioration in conditions since the report that was issued on April 1st.
California Drought Monitor reports for April 1st (top map) and May 1st (bottom map). For the first time since these reports were issued 15 years ago, the entire state of California is now experiencing drought conditions. NOAA et al.
Rainfall in April was actually close to normal for most of the state as one can see in the tables below. The worsening of the drought conditions, however, is that the strong April sunshine is increasing evaporation rates.
Total seasonal precipitation to date (July 1, 2013-May 1, 2014 top table compared to July 1-April 1 bottom table) for select California cities. The cites are arranged in geographical order from north to south.
The bottom line is that the rainy season is over and the next six months are going to be a severe test of the state’s ability to manage its meager water resources. We will probably see (and already are) clashes between agricultural concerns and urban consumers. The specter of an horrific fire season also looms over all this. It has been 37 years since a drought of this severity has affected the state and since the drought of 1975-1977 the population of California has almost doubled (from about 20 million to 38 million). The consumption of water resources by the agricultural industry has also dramatically increased. The only mitigating affect of these changes is that per capita water consumption has decreased thanks to a number of conservation innovations and regulations.
Christopher C. Burt
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