Thursday, March 22, 2018

National Drought Mitigation Center

Drought and Climate for April 2016: Drought continues to plague western 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


By the end of April, most of the drought in the United States continued to be located in the West. Above-normal precipitation across the Plains alleviated many of the areas of moderate drought and abnormally dry regions in North Dakota, Kansas, Oklahoma, and the Texas panhandle, which had been present through much of April.  In addition, wetter than normal conditions in the desert southwest also resulted in category reductions of drought in parts of California, Nevada, and Utah.  Moderate drought areas in Arizona and New Mexico expanded to include the southern parts of the states.  In the eastern half of the country, below-normal precipitation deteriorated drought conditions in the Mid-Atlantic States.  By the end of April, 15.09 percent of the contiguous U.S. was experiencing moderate drought conditions or worse, compared to 14.56 percent at the end of March.  Other categorical changes were also relatively small.  Severe drought improved from 5.85 to 5.46 percent, extreme drought improved from 3.76 to 3.44 percent, and exceptional drought improved from 1.87 to 1.11 percent of the contiguous United States. Outside of the contiguous U.S., conditions in Alaska remained relatively unchanged while continued drier than normal conditions in Hawaii expanded the abnormally dry regions on Maui, Molokai, and Oahu. Drought conditions on the Big Island deteriorated with an expansion of severe drought and an introduction of extreme drought. Puerto Rico saw improvement with the removal of severe drought conditions and a reduction in moderate drought and abnormally dry conditions.  The number of people being affected by drought increased from 45.6 million at the end of March to about 49.8 million at the end of April.

Drought Outlook

In the coming months, drought conditions are expected to persist over much of California, western Nevada, southeast Oregon, and southern Arizona and New Mexico, with some removal or improvement of conditions in scattered locations across the West and Plains.  Drought is also expected to persist over Hawaii and improve over Puerto Rico.


April temperatures deviated within 2-4 degrees of normal over much of the United States.  Exceptions were present in the Pacific Northwest, where it was 4-8 degrees warmer than normal, and in the Great Lakes region and the Northeast, where it was 2-6 degrees cooler than normal.


In April, wetter than normal conditions dominated the Great Plains, desert southwest, and Gulf Coast states, with many areas receiving in excess of 200% of their normal precipitation.  In contrast, the Pacific Northwest, coastal California, south Texas, Florida, the Northeast, and parts of the Midwest received 5-75% below normal precipitation.


Regional Overviews


April in the northeastern U.S. can be summed up as cool and dry.  The first two weeks brought a blast of Arctic air, tying or setting daily record lows and helping to drive down monthly averaged temperatures.  During this time, snow storms dumped more than a half of foot of snow on parts of the region, with enough snow falling in parts of Massachusetts and Rhode Island to set record totals.  By the end of the month, most areas had average temperatures 3-4 degrees below normal.  In addition, locations in Virginia and West Virginia were warmer than normal with average temperature departures of 3-4 degrees above normal.  Despite snow in the early part of the month, monthly precipitation in most areas was below normal, with the driest areas receiving as little as 25 percent of normal, resulting in the introduction of abnormally dry conditions in these areas.  Above-normal precipitation was present in the northern parts of Maine, Vermont, New Hampshire, eastern New York, and western Pennsylvania.


Most of the Southeast continued to experience warmer than normal temperatures.  Locations in Florida, Tennessee, Mississippi, Alabama, and Virginia saw departures of up to 5 degrees above normal.  In contrast, the coastal regions of Maryland and the Carolinas experienced colder than normal conditions.  Precipitation was more variable.  Dry conditions continued in April for Florida and in a broad swath that extends from Tennessee and northern Alabama to Maryland.  Precipitation values ranged from 5 to 70 percent of normal in these areas, with many stations experiencing conditions that fell within the top 10 driest on record.  As a result, abnormally dry conditions and moderate drought developed in these areas. Severe thunderstorms during the latter part of the month brought heavy rain and flooding to parts of Mississippi and Alabama.  By the month’s end, wetter than normal areas included parts of Mississippi, Alabama, Georgia, and parts of North Carolina.

Movers & Shakers for March 2016

Percent area Mar. 29, 2016

Percent area May 3, 2016 Status Percentage point change
Biggest increases in drought
Arizona 53.97 66.75 Moderate 12.78
Georgia 0
Moderate 12.32
Hawaii 17.11
Severe 22.79
Nevada 59.3
Moderate 3.03
New Mexico
North Carolina 0
13.40 Moderate 13.40
South Carolina
Moderate 7.75
Tennessee 0
West Virginia
Biggest improvements in drought
Extreme 6.1
34.74 21.04 Exceptional 13.7
Colorado 4.39 0 Moderate
Hawaii 78.48 60.92 Moderate 17.56
Idaho 3.16
Moderate 3.16
Kansas 22.2
Montana 12.37 7.87 Moderate 4.5
3.46 0 Severe 3.46
North Dakota
Oregon 45.68 26.12 Moderate 19.56
Utah 30.09
Severe 12.79
Wyoming 13.78
 6.85 Moderate
Puerto Rico
Moderate 13.94


The first half of April began with well below normal temperatures across much of the region, resulting in multiple daily record low temperatures.  In the latter half of the month, above-normal temperatures were common across the southern half of the region, while the northern half had spells of both colder and warmer than normal temperatures. When all the numbers were in, this resulted in a gradient across the region, with areas in the northeastern part recording monthly averaged temperature departures ranging from near normal to more than 5 degrees below normal.  Remaining areas recorded above-normal monthly averaged temperatures, with departures of up to 5 degrees above normal in parts of Missouri. Precipitation was more variable.  The first half of the month saw multiple storm systems and above-average precipitation in areas surrounding the Great Lakes and in the northern half of the Ohio Valley, while much of Minnesota, Iowa, and northern Illinois saw below-normal precipitation.  The latter half of the month had periods of both above- and below-normal precipitation.  Monthly averaged values show precipitation deficits of less than 50 percent of normal in southeastern Minnesota, northeast Iowa, and southwestern Wisconsin. Monthly averaged precipitation surpluses were recorded in the northern and westernmost parts of the region, with the wettest areas receiving in excess of 200% of normal precipitation. Moderate drought developed over southern Missouri, while the remainder of the region remained virtually drought free.

High Plains

In April, the High Plains generally saw normal to above-normal temperatures.  Exceptions include areas in the Dakotas with temperatures 2-6 degrees below normal. April was also wet in the High Plains.  Slow-moving storm systems in the latter half of the month brought widespread rain to the region and set daily precipitation records in locations in Nebraska.  By the end of the month, all states had locations receiving more than 200% of their normal precipitation, eliminating drought conditions in these areas.  A few dry pockets in Colorado, South Dakota, and Wyoming received less than 50% of their normal precipitation.


Temperatures in the South ranged from slightly below normal to slightly above normal in the month of April. Most of the region was very wet as thunderstorms brought record rainfall mid-month, with some areas in Texas receiving a season’s worth of rainfall in one night. At month’s end, parts of Oklahoma, Texas, and Louisiana recorded totals in excess of 300% of their normal precipitation, and the majority of the areas in these states were drought free. In contrast, Tennessee, west and southern Texas, and areas in Louisiana and Mississippi received from 5 to 50% of their normal precipitation.


Temperatures in April varied from more than 6 degrees above normal in parts of the Pacific Northwest to slightly below normal in the desert southwest.  April brought drier than normal conditions to the Pacific Northwest and coastal Southern California, with the driest areas receiving less than 25% of their normal precipitation.  Locations in Washington and Oregon recorded monthly totals that ranked in the top 10 driest Aprils on record. The desert southwest and Rocky Mountain regions all saw above-normal precipitation, with the wettest areas in Southern California and southern Nevada recording over 400% of their normal precipitation and setting records in the top 5 wettest.





April 2016 impact summary: Rainfall over Great Plains eases wheat crop concerns; parts of California see greener landscapes

The two charts above summarize information from the Drought Impact Reporter.
The two charts above summarize information from the California Department of Water Resources Water Conditions page.

By Denise Gutzmer, NDMC Drought Impact Specialist

Lovely April showers eased developing drought in the northern and southern Great Plains, soothing concerns about dry weather and the wheat crop.  Parts of California luxuriated in rainfall, too, as the landscape greened with the addition of water.  But parts of Oregon, Utah, Missouri and the eastern U.S. slipped into a drier trend as drought increased in those states.  Sixty-nine impacts were added to the Drought Impact Reporter in April, with 33 for California and its water issues; 10 for North Carolina, thanks to its busy Community Collaborative Rain, Hail and Snow Network observers; and three or fewer for other states.

Larger water allocations announced in California

With near-average snowfall in California’s Sierra Nevada this winter, state and federal water projects increased their initial water allocation estimates.  The California Department of Water Resources announced that it will deliver 60 percent of water allotments for agricultural and municipal use as March storms brought more rain to refill reservoirs, particularly in the northern part of the state.  The Central Valley Project, operated by the U.S. Bureau of Reclamation, will provide 50 percent of full allocations for Friant Division contractors of Class 1 water supply.  The larger offerings were extremely welcome after years of meager allocations.

California loosens water cutbacks in drought,” by Associated Press, Orange County Register (Santa Ana, Calif.), April 21, 2016

State, federal water sellers increase allocations,” by Central Valley Business Times (Stockton, Calif.), April 21, 2016

West experiences early snow melt

Much of the West had snowpacks that were near normal in early April, but warm temperatures brought rapid melting, the likes of which climatologists have not seen in nearly forty years.  Unfortunately, this will leave less runoff later in the spring and summer, which could bring an early end to water deliveries.  Below 5,000 feet in the Washington Cascades, snow melted two to three weeks early, putting the snow level at 5,000 to 5,500 feet. 

Snowpack is melting fast, despite April storms,” by Paige Blankenbuehler, High Country News (Paonia, Colo.), April 24, 2016

 “Rapid Washington snowmelt fills streams,” by Dan Wheat, Capital Press (Salem, Ore.), May 5, 2016 

California water districts railing against conservation order

The healthier water reserves in Northern California where winter precipitation fell more abundantly led water providers to push for more control over conservation in their districts rather than having the state dictate conservation goals.  Environmentalists argued for continued conservation, but at a relaxed rate.  The State Water Resources Control Board, however, was adjusting restrictions to better fit the current situation of water aplenty in the north, but ongoing drought in the south, and should reveal new conservation measures in May.

California rethinks approach to conserving water in drought,” by Scott Smith, Associated Press, SFGate, April 20, 2016

North Coast water conservation slackens as drought dissipates,” by Will Houston, Eureka Times-Standard (Calif.), May 4, 2016

Los Angeles residents may face higher fines for excessive water use

In one of the Southern California cities still dealing with drought, residents of Los Angeles are facing the possibility of higher fines and water audits if they use excessive amounts of water after Mayor Eric Garcetti approved a new water conservation plan, which took effect on May 2.  The Los Angeles Department of Water and Power can fine customers from $1,000 to $40,000 per month for what it considers “unreasonable use” of water while Los Angeles is in an elevated phase of its emergency drought plan.

L.A.'s water wasters will soon face heavier fines and audits,” by Matt Stevens,  Los Angeles Times, April 27, 2016

El Niño on the way out, La Niña coming

This winter’s strong El Niño was a disappointment in that it didn’t bring the abundant, drought-ending storms as hoped.  More bad news is that the National Oceanic and Atmospheric Administration's Climate Prediction Center (CPC) forecasts a La Niña to develop in the fall.  CPC deputy director Mike Halpert said that it will likely mean dry weather for the U.S. Southwest and parts of California.  Drought relief does not appear to be in sight.

 “El Niño weakens, here comes La Niña, meteorologists say,” by Seth Borenstein, Associated Press, April 14, 2016

Busy 2016 wildfire season predicted in drier areas

The National Interagency Fire Center predicted the 2016 fire season to be busier from May throughout the summer in drier areas, such as the Southwest, Hawaii and Alaska, as dry weather increases the fire danger.  In California, winter precipitation encouraged the growth of grasses and new vegetation that is drying out and could fuel this year’s wildfires.  Some areas have thicker, taller grass than locals have seen in quite a while.  Bark beetles also have killed many drought-stressed trees, adding to the available fuel.  The deaths of many of the state’s ponderosa pines from drought and western bark beetles prompted several organizations to take steps to remove the dead trees to reduce the amount of fuel available for wildfires. California homeowners were also urged to create a defensible space of 100 feet around their homes.

Hawaii, Alaska, Southwest face increased danger of wildfires,” by Associated Press, Honolulu Star Advertiser, May 1, 2016              

National Significant Wildland Fire Potential Outlook from the National Interagency Fire Center

El Niño rains added fuel to California's upcoming fire season, experts say,” by Joseph Serna, Los Angeles Times, May 5, 2016

Cal Fire Urges State to Prepare with "Ready, Set, GO" Campaign,” by Kaitlin Lewis, KFBK News (Sacramento), May 2, 2016

California to remove dying pines, hoping to prevent fires,” by Associated Press, Napa Valley Register (Calif.), April 25, 2016

Fire season off to an early start in New Mexico, Arizona

New Mexico’s fire season has taken off early with more than 130 wildfires and more than 45,000 acres burned by April 2, a big increase over the 2015 fire season.  Moisture was more plentiful in 2015, supporting the growth of grasses that have since dried out and become fuel for 2016’s wildfires.  The fire danger was high in Arizona, too, and could become extremely high if the next few months are hot and dry.  Nearly 300 fires have already burned in 2016 and charred more than 21,000 acres, compared to about half the number of wildfires by this time in 2015.

Fire season in New Mexico off to early start,” by Ollie Reed Jr., ABQJournal (Albuquerque, N.M.), April 2, 2016

State officials discuss increased potential for wildfires,” by Ryan Van Velzer, KPHO-TV CBS 5 (Phoenix), April 13, 2016

Water conservation a priority for Californians

A Field Research Corporation survey of 800 registered California voters found that 62 percent believe the state faces an extremely serious water shortage and intend to continue conserving water.  Interestingly enough, 68 percent of Northern Californians thought the drought was extremely serious, while just 60 percent of Southern Californians felt that way, even though SoCal missed out on much of the precipitation this winter. 

Poll: Most Californians see serious water shortage despite rains,” by Laurel Hamers and Lindzi Wessel, San Jose Mercury News (Calif.), April 15, 2016

Californians demonstrated their concern for the water supply when the public, the bottled water industry and environmental activists responded passionately to the U.S. Forest Service’s proposal to grant Nestlé a new permit to continue pumping water out of the San Bernardino National Forest. The Forest Service received a petition with more than 280,000 signatures from people insisting that the Forest Service undertake a “thorough and unbiased” environmental impact review, 568 letters, emails, and other written comments at its website. Nestlé’s permit expired in 1988, but the company continued to take 36 million gallons in 2015.

Nestle water permit debate heats up, 280K sign petition,” by Ian James, The Palm Springs Desert Sun (Calif.), May 4, 2016

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