The area of California in exceptional drought, the worst category, increased across most of San Luis Obispo County on the U.S. Drought Monitor map released today, and the nation as a whole saw all categories of drought edge upward.
Drought in the 48 contiguous states has increased more than 4 percentage points in the last four weeks to 37.38 percent, said Brad Rippey, a meteorologist in the U.S. Department of Agriculture’s Office of the Chief Economist. Drought coverage had fallen to 30.28 percent on December 10, 2013; that figure represented the smallest drought coverage since Dec. 27, 2011.
“The extent of the two most serious drought categories—extreme to exceptional (D3 to D4) drought—nearly doubled in the last four weeks from 4.13 to 7.37 percent,” Rippey said. “That change was driven by deteriorating conditions in California. During the four-week period ending Feb. 4, California’s coverage of extreme to exceptional drought surged from 27.59 to 67.13 percent. California also experienced its first-ever coverage of exceptional drought (D4) in the nearly 15-year history of the U.S. Drought Monitor, beginning on Jan. 28. By Feb. 4, nearly one-tenth (9.81 percent) of California was considered to be in D4.”
“The Western winter wet season has largely been a bust, and not just in California,” Rippey said. “Drought covers more than half of eight of the eleven Western States—all but Colorado, Montana, and Wyoming. California has been drier this winter than each of the previous two. According to the California Department of Water Resources, the average water content of the high-elevation Sierra Nevada snowpack stands at three inches, just 15 percent of the early-February normal.”
USDM change map for the four weeks ending Feb. 4, 2014
The good news is that the forecast offers prospects for significant precipitation, now that the ridge of high pressure that had been blocking normal winter precipitation has broken down. “Five-day precipitation totals could reach four to eight inches in drought-stricken northern California,” Rippey said. “Somewhat lighter but still highly beneficial precipitation—as much as two to four inches—may occur in the southern Cascades and northern Intermountain West.”
It will take more than one good rain to end the long-term drought. California began seeing some rain this week.
Anthony Artusa, this week’s U.S. Drought Monitor author, said in narrative accompanying the map, “The precipitation received this week only keeps the snowpack/water supply from falling further behind. Reservoirs continue to go down. An eight-station index for the northern Sierras (which represents an average of eight precipitation gauges that span the area from Lake Tahoe to up above Lake Shasta), indicates precipitation amounts of 4.5 inches since the beginning of the Water Year (Oct 1, 2013). Last year at this time, 34.3 inches of precipitation fell, while the average to date is 26.4 inches.”
“Two of the larger reservoirs in the County, near the border with Monterey County, are at 5-percent capacity (Lake Nacimiento and Lake San Antonio),” Artusa said. “The City of Cambria is implementing water restrictions for residents, while many cattle owners are selling off their herds due to lack of feed and water.”
To the north, Artusa said, “The higher elevations of western Washington and western Oregon received 2-5 inches of precipitation (liquid equivalent, locally heavier) during the past week, though as is the case with California, significantly more precipitation will be needed to overcome longer-term deficits.”
Examining the effects of drought on agriculture, Rippey said, “On the Plains, winter wheat condition declined during January due to dry, windy weather and sharp temperature fluctuations. During several January cold outbreaks, some of the Plains’ wheat was exposed to sub-zero temperatures without the benefit of snow cover. According to USDA, the portion of the wheat rated good to excellent fell during January from 70 to 60 percent in South Dakota; 65 to 46 percent in Nebraska; 60 to 46 percent in Montana; 63 to 36 percent in Oklahoma; and 58 to 35 percent in Kansas. Texas wheat, already stressed by drought, was rated 19 percent good to excellent and 41 percent very poor to poor by the end of January.”
“Although the decline in wheat condition was not entirely driven by drought, the portion of the U.S. winter wheat crop in drought rose to 49 percent by Feb. 4 -- up from 34 percent on Jan. 7 and 30 percent as recently as Dec. 3, 2013,” Rippey said. “There have been less significant, but still noteworthy, rises recently in domestic cattle inventory in drought (40 percent on Feb. 4) and U.S. hay in drought (26 percent).”
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. This week’s U.S. Drought Monitor author, Anthony Artusa, is with NOAA’s Climate Prediction 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