Thursday, April 19, 2018

National Drought Mitigation Center

Drought and Climate for December 2017: Drought intensifies across the Southwest and southern United States

Access the latest monthly drought outlook from NOAA's Climate Prediction Center.
The two maps above are from the High Plains Regional Climate Center.
Find these and other products related to the U.S. Drought Monitor on the USDM website.

By Deborah Bathke, NDMC Climatologist


The area of the contiguous United States impacted by drought increased from 21.14 percent at the beginning of December to 27.70 percent by month’s end.  Areas in severe drought increased from 4.88 to 7.46 percent, as drought intensified across the Southwest and southern Plains.  Extreme drought decreased slightly from 1.03 to 0.83 percent, largely in response to heavy rains over the lower Mississippi and Tennessee valleys.  No areas of exceptional drought were present.  January began with 61.9 million people being impacted by drought compared to 44.6 million at the beginning of December. 

Compared to last year at this time, the area of the contiguous United States impacted by drought is up by nearly 23 percent, while the population being affected is down by 48 percent.  These differences reflect the shift in worst drought conditions from the highly populated areas of central and southern California, the Southeast, and New England in January 2017 to the more sparsely populated regions of the northern Plains in January 2018.

Drought Outlook

The Climate Prediction Center’s Monthly Drought Outlook projects continued drought reductions in eastern Texas and the lower Mississippi Valley based on climatology and anticipated wet conditions.  Improvements are also possible for western Montana because of recent precipitation and favorable snowpack conditions.  Elsewhere in the country, drought areas are expected to persist or expand.


Above-average temperatures dominated the Southwest during December, with parts of Southern California, Arizona, and New Mexico experiencing temperatures of 8 to 12 degrees above normal and setting monthly temperature records.  Alaska also set a statewide temperature record with locations in the state experiencing temperatures ranging from 2 to 21 degrees above normal.  Other areas experiencing above-average temperatures included parts of the Plains and Southeast, where temperatures varied from 1 to 5 degrees above normal.  Near- to below-average monthly temperatures were observed across parts of the Northwest, Midwest, and Northeast.  Across the central and northern Plains, the beginning of December was much warmer than average, with temperatures ranging from 8 to 15 degrees above normal.  The month ended with a record and near-record cold week for many locations, with temperatures ranging from 11 to 33 degrees below normal.


The contiguous United States experienced its ninth driest December on record.  Much of the West, parts of the central Plains, the Midwest, and Mid-Atlantic region experienced below-average precipitation, with deficits generally amounting to less than 50 percent of normal.  Parts of the Northern Rockies, northern Great Lakes Region, southern Plains, and Lower Mississippi Valley were wetter than average, with departures ranging from 110 to more than 300 percent of normal.

Regional Overviews


Temperatures in the Northeast were generally below average for the month, with the coolest temperatures (5 to 7 degrees below average) recorded in upstate New York, Vermont, New Hampshire, and Maine.  It was dry across most of the region, with deficits generally ranging from 1 to 3 inches during December.  During the month, moderate drought was introduced in eastern Pennsylvania and Maryland and abnormal dryness generally expanded in the region.  December ended with 5.25 percent of the region in drought.


Cooler than normal temperatures were recorded in West Virginia, North Carolina, and western Alabama while most of South Carolina, Georgia, southeast Alabama, and Florida were 1 to 4 degrees warmer than normal. Precipitation across the coastal Carolinas was 0.6 to 2.6 inches above normal while much of the rest of the region had monthly totals of 1 to 3 inches below normal.  With the warmth and dryness, drought conditions spread in the region; December ended with 33.15 percent of the region in drought compared to 14.86 percent at the end of November.

Movers & Shakers for December 2017

Percent area November 28, 2017

Percent area January 2, 2018 Status Percentage point change
Biggest increases in drought
Alabama 13.3 26.6 Moderate 13.3
Arizona 73.1 100.0 Moderate 26.9
2.1 28.7 Severe 26.6
California 8.2 12.7 Moderate 4.5
Colorado 13.2 33.5 Moderate 20.3
0 7.3 Severe 7.3
Florida 12.3 22.4 Moderate 10.1
Georgia 13.8 40.7 Moderate 26.9
Illinois 4.1 16.2 Moderate 12.1
Kansas 15.3 32.7 Moderate 17.4
0 8.8 Severe 8.8
Louisiana 18.9 33.4 Severe 14.5
Maryland 0 44.3 Moderate 44.3
Mississippi 0 10.5 Severe 10.5
Missouri 39.6 46.3 Moderate 6.7
16.6 23.7 Severe 7.1
Nevada 0.1 3.4 Moderate 3.3
New Mexico 16.2 46.0 Moderate 29.8
0 4.8 Severe 4.8
North Carolina 21.9 35.3 Moderate 13.4
North Dakota 48.1 60.6 Moderate 12.5
Oklahoma 39.9 77.2 Moderate 37.3
20.8 38.8 Severe 18.0
Pennsylvania 0 13.8 Moderate 13.8
South Dakota 49.1 52.8 Moderate 3.7
Utah 52.0 61.4 Moderate 9.4
0 19.6 Severe 19.6
Virginia 3.9 51.9 Moderate 48.0
Biggest improvements in drought
Arkansas 85.2 71.3 Moderate 13.9
61.3 32.0 Severe 29.3
14.7 2.4 Extreme 12.3
Hawaii 26.3 21.3 Moderate 5.0
7.0 0.9 Severe 6.1
Mississippi 56.8 39.6 Moderate 17.2
Montana 53.5 42.0 Moderate 11.5
30.2 26.8 Severe 3.4
South Carolina 27.3 21.8 Moderate 5.5


Temperatures in the South ranged from 1 degree below normal across parts of Tennessee and the Gulf Coast to 4 degrees above normal in West Texas. A swath of above-normal precipitation stretched from southern Texas to western Tennessee and along the Gulf Coast, where departures were generally from 0.5 to 3 inches above normal.  Near- to below-normal precipitation prevailed across the remainder of the region, with deficits ranging from 0 to 3 inches.  Moderate drought expanded slightly during the month, now covering 42.64 percent of the region compared to 41.44 at the beginning of the month.  Severe drought increased from 13.44 to 15.33 percent and extreme drought decreased from 1.59 to 0.30 percent.


The northern and eastern parts of the region were 1 to 5 degrees cooler than normal while the western and southern areas were 1 to 4 degrees warmer than normal.  Dry conditions dominated much of the Midwest, with deficits of 1 to 2 inches common for most of the region except northern Michigan, where departures were about an inch above normal.  Overall, the extent of drought in the Midwest increased from 6.98 to 9.46 percent.  Severe drought increased from 2.40 to 3.44 percent and extreme drought was introduced into southern Missouri, now accounting for 0.18 percent of the region.

High Plains

Temperatures in the High Plains ranged from 5 to 14 degrees above normal in the first half of December to 2 to 29 degrees below normal during the last week of the month.  Much of the region experienced near- to below-normal precipitation.  Deficits of 0.5 to 1.2 inches occurred across southeast Nebraska and Kansas.  Areas receiving above-normal precipitation included parts of western South Dakota, the Nebraska Panhandle, and eastern Wyoming, which recorded monthly surpluses of 0.6 to 0.9 inches. Drought conditions continued to develop in the region.  Moderate drought increased from 19.97 percent to 29.19 percent and severe drought increased from 3.44 to 6.34 percent. Exceptional drought remained unchanged at 0.90 percent of the region.


The Northwest was generally cooler than normal in December, with temperatures ranging from 1 to 3 degrees below normal. Temperatures in the southern part of the region were generally 1 to 4 degrees above normal.  Most of the region was at or below normal precipitation, with areas of northern Idaho, Montana, and central Colorado above normal for the month. The greatest departures were in western Oregon and northern California, with departures of more than 6 inches below normal. The dryness and heat in the Southwest allowed for the continued expansion of drought. December ended with 29.03 percent of the region in moderate drought compared to 21.48 percent at the end of November.  Severe drought increased from 3.94 to 8.60 percent and extreme drought remained steady at 1.52 percent.



December 2017 impact summary: Agricultural producers face challenges across southern United States

The two charts above summarize information from the Drought Impact Reporter.

By Denise Gutzmer, NDMC Drought Impact Specialist

Drought expanded considerably in the southern United States in December to cover more of the Southwest, the central United States, and parts of the East Coast, while rain fell to ease drought from parts of Texas to South Carolina.  During this time, 76 impacts were added to the Drought Impact Reporter, with most of those about conditions in Texas as many Community Collaborative Rain, Hail and Snow (CoCoRaHS) network observers shared their experiences with plant and wildlife-related impacts.  Missouri and Oklahoma also had several agricultural and wildlife-related impacts, with eight and seven impacts, respectively.


Amid a dry fall, crops suffered in the Texas Panhandle and other parts of the state.  The wheat crop and rangelands in the Texas Panhandle dried out quickly as rain continued to miss the area, leading producers to move their livestock off dryland pastures.  CoCoRaHS reports indicated ponds shrinking, crunchy grass, excessive dust, and other similar events.

Dry temperatures affecting wheat crops in the Panhandle, by Nyzah McDonald, KFDA-TV News Channel 10 (Amarillo, Texas), Dec. 7, 2017

By early January, the city of Amarillo had recorded more than 70 days since the last measurable precipitation, with concerns rising about the fire danger and blowing dust.  Numerous counties in the Panhandle, the south, and the west adopted burn bans to reduce the likelihood of wildfires after poor rainfall in the fall led to the landscape becoming very dry with a high fuel load in some areas.

Drought Conditions Return to the High Plains, by Angelina Perez, (Amarillo, Texas), Jan. 4, 2018

Bell County bans certain types of fireworks for the holidays, by Stephen Adams, KCEN-TV NBC 6 (Texas), Dec. 11, 2017

Agricultural challenges in Missouri, Oklahoma

The Missouri landscape showed signs of drought as individuals and CoCoRaHS observers described dry grass and early hay feeding for livestock.  Some were feeding hay months early at a substantial cost and selling cattle to compensate for the lack of pasture.  Some producers noted low pond levels and expressed concern about water supplies for livestock.

Oklahoma producers were experiencing some of the same issues of having no pasture and selling calves early rather than feeding them through the winter.  The auction in Woodward was exceptionally busy in December with around 4,000 head for sale as producers tried to make the best choices for their situation.  In addition to feeding hay, protein supplements were another cost that growers took on earlier than usual. 

Dry start to California's wet season

December remained dry in California, making water managers a bit nervous, although plenty of the wet season still loomed for the state.  The Los Angeles area received 0.11 inches—just a tiny fraction of the more than 2 inches of precipitation normally received from October 1 through the first week of December, while many other southern California cities saw the same near-record dry starts to the wet season as a ridge over the West Coast blocked storms.

The first manual snow survey in the Sierra Nevada mountains revealed just 3 percent of normal snowpack in some areas, as the start to the winter season remained unsettlingly dry.  Thanks to last year’s atmospheric rivers, the state’s reservoirs are still in good shape, and there is ample time remaining for big snowstorms to deepen the snowpack.

Just subtract water - how a dry spell allowed winds to lash California with flames, by Alex Dobuzinskis, Reuters, Dec. 7, 2017

Record-breaking dry conditions are making Southern California wildfires much harder to fight, by Lauren Williams, Los Angeles Daily News, Dec. 10, 2017

California’s first 2018 survey finds little snow, by The Associated Press, KRON TV NBC 4 (San Francisco), Jan. 3, 2018

California: Hardly Any Snow but Not in Drought Again, Yet, by The Associated Press, The New York Times, Jan. 3, 2018

Largest fire in California's history

The dry conditions also contributed to the Thomas Fire, the largest in the state’s history. The fire began on December 4, and, driven by Santa Ana winds, consumed nearly 282,000 acres and more than a  thousand homes in Ventura and Santa Barbara counties.  Such a large fire would be expected during the summer, but to have this blaze in December is unprecedented.  The flames were not yet fully contained even in early January.

Thomas Fire at InciWeb 

California wildfire becomes largest on record in the state, Reuters, Dec. 22, 2017


For more drought information, please visit the Drought Impact Reporter.



The National Drought Mitigation Center | University of Nebraska-Lincoln
3310 Holdrege Street | P.O. Box 830988 | Lincoln, NE 68583–0988
phone: (402) 472–6707 | fax: (402) 472–2946 | Contact Us | Web Policy

University of Nebraska-Lincoln
Copyright 2018 National Drought Mitigation Center