Persistent dry conditions in the West led to an expansion of drought in the week that ended Jan. 7, with most of the recent change in Oregon and Washington, said U.S. Drought Monitor authors.
The map now shows 33.22 percent of the contiguous 48 states in drought, up from 30.95 percent a week earlier, and up from 30.28 percent on Dec. 10, which was the least area in drought for any week of 2013, and the smallest drought coverage since Dec. 27, 2011, said Brad Rippey, meteorologist in the U.S. Department of Agriculture’s Office of the Chief Economist.
“Most of the recent increase in U.S. drought coverage has been due to a lack of cold-season precipitation in the West,” Rippey said. “In particular, drought coverage has sharply increased in Oregon, from 38 to 88 percent between Dec. 10 and Jan. 7. Similarly, Washington had no drought depicted on Dec. 10, but more than half (55 percent) of the state was experiencing drought on Jan. 7.”
“Western drought concerns are most acute in those areas—including California—moving deeper into a third consecutive year of drought,” Rippey said. “According to the state Department of Water Resources, California’s 154 intrastate reservoirs were collectively brimming with water (125 percent of average storage) on Nov. 30, 2011. In subsequent years, as drought moved past the one- and two-year marks, storage fell to 97 and 74 percent of average, respectively, on Nov. 30, 2012 and 2013. Without a sudden reversal in California’s dry weather pattern from January to March 2014, there will be little snow in the Sierra Nevada to melt and feed the reservoir system.”
four-week U.S. Drought Monitor change map
The U.S. Drought Monitor, which is not the official source of drought declarations in California, has shown significant portions of the state in various degrees of drought since January 2012.
This week’s U.S. Drought Monitor author, Mark Svoboda, said in narrative accompanying the map that in the West, “There seems to be no relief in sight as the calendar flips over to 2014. … [C]oncern for water supply, fire and other impacts grows each week the rains and snows don’t come. In fact, many locations in California reported the calendar year 2013 as being the driest on record, smashing previous prior record dry years, including 1976. One such example is Shasta Dam, where only 16.89 inches was reported in 2013, more than 11 inches below the previous record low of 27.99 inches in 1976. Shasta’s calendar year average is 62.72 inches. Upper elevation Sierra station snowpack and snow water equivalent values in California have been abysmal for the Water Year (since October 1) as well.”
Rippey said recent weeks have seen little change in hay or cattle in drought nationwide. “Hay in drought has hovered in the 21- to 22-percent range for 10 consecutive weeks,” he said. “Similarly, cattle in drought has remained in the 34- to 36-percent range for 10 weeks in a row. Winter wheat in drought has edged upward in recent weeks, from 31 to 34 percent between Dec. 10 and Jan. 7. Most of the drought concern for winter wheat exists across the central and southern High Plains, with some of the driest conditions—both at short- and long-term times scales—being noted in the panhandles of Texas and Oklahoma, as well as parts of adjoining states.”
U.S. Drought Monitor authors synthesize many drought indicators into a single map that identifies areas of the country that are abnormally dry (D0), in moderate drought (D1), in severe drought (D2), extreme drought (D3) and exceptional drought (D4). The map is released each week based on data through the previous Tuesday morning.
The U.S. Drought Monitor map is jointly produced by the National Drought Mitigation Center at the University of Nebraska-Lincoln, the National Oceanic and Atmospheric Administration, the USDA, and about 350 drought observers across the country. Svoboda, a climatologist, leads the Monitoring Program Area at the National Drought Mitigation Center.
Statistics for the percent area in each category of drought are automatically added to the U.S. Drought Monitor website each week for the entire country and Puerto Rico, for the 48 contiguous states, for each climate region, and for individual states. U.S. Drought Monitor data online goes back to January 2000.
http://drought.unl.edu/MonitoringTools/USDroughtMonitor/DroughtMonitorTips.aspx
U.S. Drought Monitor map, statistics and narrative summary: http://droughtmonitor.unl.edu
U.S. Ag in Drought, current: http://www.usda.gov/oce/weather/Drought/AgInDrought.pdf
archived: http://drought.unl.edu/Planning/Impacts/USAginDroughtArchive.aspx
U.S. Drought Monitor Change Maps: http://droughtmonitor.unl.edu/DataArchive/ChangeMaps.aspx
Drought Impact Reporter: http://droughtreporter.unl.edu
National Drought Mitigation Center’s Monthly Drought and Impact Summary
http://drought.unl.edu/NewsOutreach/MonthlySummary.aspx
National Climatic Data Center’s State of the Climate Drought Summary:
http://www.ncdc.noaa.gov/sotc/drought/
U.S. Monthly Drought Outlook:
http://www.cpc.ncep.noaa.gov/products/expert_assessment/mdo_summary.html
U.S. Seasonal Drought Outlook:
http://www.cpc.ncep.noaa.gov/products/expert_assessment/sdo_summary.html
-- Kelly Helm Smith, National Drought Mitigation Center