Thursday, March 22, 2018

National Drought Mitigation Center

April 2015 Drought and Impact Summary

Drought and Climate

by Brian Fuchs, NDMC Climatologist


Above-normal precipitation over the southern and southeastern United States as well as the Ohio River Valley brought improvements to drought, while other areas saw drought develop and intensify. During April, drought conditions expanded from 36.84 to 37.41 percent of the contiguous United States. Severe drought worsened from 18.60 to 20.03 percent, extreme drought improved from 8.97 to 8.10 percent and exceptional drought worsened from 3.34 to 3.41 percent. There were no drought issues in Alaska and Puerto Rico. Drought improved in Hawaii, covering 23.33 percent of the islands at the end of April compared to 26.36 percent at the end of March. April ended with 73.7 million people in drought compared to 80.0 million at the end of March, mainly due to improvement in population centers of the southern Plains.


Much of the current drought over the western United States will persist in May. The same is true for drought areas in the upper Midwest and central Plains. For the southern Plains, forecasters anticipate improvements, with drought likely to be completely removed in some areas. With continued dryness on Puerto Rico, drought may develop there.


Most of the country recorded above-normal temperatures for April, with the warmest readings over the Southeast, where departures were 6-8 degrees above normal for the month. California and the central and northern Plains were 2-4 degrees warmer than normal.  An exception was areas of the Southwest and west Texas that were 2-4 degrees below normal in April.


An area from east Texas across southern Louisiana experienced the greatest precipitation in April, recording rainfall that was 6-12 inches above normal. Portions of Florida, Georgia, Alabama, Oklahoma, and Kentucky were also 3-6 inches wetter than usual during the month. Conditions over the West, Midwest and New England were generally as much as 3 inches drier than normal.

Regional Overviews

Movers & Shakers for April 2015

Percent area
March 31, 2015
Percent area
April 28, 2015
Status Percentage point change

Biggest increases in drought
41.41 46.77 exceptional 5.36
Idaho 39.05 48.07 moderate 9.02
15.46 21.83 severe 6.37
2.41 8.18 extreme 5.77
Kansas 22.45 26.18 severe 3.73
Minnesota 0.00 31.88 severe 31.88
Nebraska 22.49 28.15 moderate 5.66
Nevada 79.50 87.00 severe 7.50
North Dakota
21.14 27.42 moderate 6.28
Oregon 82.30 86.90 moderate 3.79
49.93 63.17 severe 15.24
South Dakota
42.78 77.10 moderate 34.32
15.98 severe 15.98
Washington 28.13 48.96 moderate 20.83
0.00 15.20 severe 15.20
Wyoming 7.60 14.31 moderate 6.71
Biggest improvements in drought
13.79 0.00
moderate 13.79
Colorado 39.75 35.92 moderate 3.83
Florida 9.13 5.14 moderate 3.99
Hawaii 26.36 23.33 moderate 3.03
Louisiana 18.54 0.00 moderate 18.54
Mississippi 3.76 0.00 moderate 3.76
New Mexico
62.11 55.64 moderate 6.47
Oklahoma 68.62 59.29 moderate 9.33
50.68 47.51 severe 3.17
37.38 24.34 extreme 13.04
8.41 4.13 exceptional 4.28
Texas 36.62 30.71 moderate 5.91
25.44 15.83 severe 9.61
15.10 5.57 extreme 9.53
Utah 51.83 45.74 severe 6.09
Wisconsin 55.36 48.08 moderate 7.28


Temperatures were mixed, with areas in the north part of the region 2-4 degrees below normal, and areas in the south part of the region 1-2 degrees above normal. The coastal regions and upper New England remained dry, with departures of up to 3 inches below normal for the month. Drought did not develop in the Northeast region and only some pockets of dryness remained.


A wet month in the Southeast region improved conditions, despite above-normal warmth. Temperatures were above normal over the entire region, with portions of Florida 6-8 degrees warmer than normal. Most areas were 2-6 degrees above normal. Georgia and Alabama were the wettest parts of the region, with 3-6 inches more rainfall than usual.  Most of the region was up to 3 inches above normal. Drought conditions improved, with only 1.01 percent of the area in drought at the end of April compared to 4.28 percent at the end of March.


Temperatures were well above normal in the Midwest in April, typically by 2-4 degrees, although portions of northern Michigan and the Upper Peninsula were 2-3 degrees cooler than normal. Precipitation was mixed in April, with some areas above normal and others below. The wettest regions were from southern Illinois to Ohio and most of Kentucky, where it was generally 2-4 inches wetter than normal. Portions of Iowa and Wisconsin were also up to 2 inches wetter than normal. Most other areas were dry and ended the month below normal. Drought improved slightly during the month, mainly in Wisconsin, with 21.18 percent of the region in drought at the end of April compared to 21.85 percent at the end of March. Drought intensified in Minnesota, putting 5.39 percent of the region in severe drought at month’s end.

High Plains

Temperatures in the High Plains were warmer than normal for the month, by 2-4 degrees in most of the area. As in the Midwest, the High Plains had a mix of areas above and below normal for precipitation in April. Much of Nebraska and Kansas were up to 3 inches wetter than normal, while much of eastern South Dakota was up to 3 inches drier than normal. Drought worsened in the region during April, with 43.87 percent of the area in drought compared to 35.96 percent in March. Severe drought worsened from 11.90 to 14.22 percent of the area, and extreme drought worsened from 0.30 to 0.51 percent.


Most of the South region was 2-4 degrees warmer than normal in April, with the area along the Big Bend of Texas being the exception. It was a wet month, with almost all areas above normal for precipitation. The greatest amounts recorded were over east Texas, southwest Oklahoma, southern Arkansas, and southern Louisiana. Southern Louisiana had readings of up to 12 inches above normal for April. With the widespread precipitation, drought receded. Drought covered 23.41 percent of the region at the end of April, compared to 29.63 percent at the end of March. Severe drought improved from 19.60 to 14.32 percent, extreme drought improved from 12.60 to 6.05 percent, and exceptional drought improved from 2.79 to 1.57 percent.


Most of the region was warmer than normal in April, although pockets of below-normal temperatures occurred in several states, notably Nevada, Idaho, Oregon, and New Mexico. Most of the region was dry, as the climatological wet season ended. It was driest along the northwest coast, where most areas got three inches less precipitation than normal for the month. Portions of Wyoming, Colorado and New Mexico were slightly wet. Drought spread in the region during April, with 62.12 percent of the area in drought at the end of April, compared to 59.80 at the end of March. Severe drought worsened from 36.89 to 39.33 percent of the area, extreme drought worsened from 17.04 to 17.64 percent and exceptional drought worsened from 7.23 to 7.95 percent.


April 2015 Drought Impacts: Water shortages affecting utilities, farmers, wells, wildlife and more in much of the West

Of 102 impacts in the Drought Impact Reporter for April 2015, the largest portions concerned water supply and restrictions.
California had the most impacts reported in April 2015, at 68, followed by Nevada, at 11, and Texas, at 9.

Secretarial disaster designations through May 6 covered most of the West and the southern Plains.
All of the reservoirs tracked on the graphic above, from the California Department of Water Resources, were below their historic averages.

By Denise Gutzmer, Drought Impact Specialist

Concerns over water restrictions and supplies intensified during April as it became abundantly clear that snowpack was on the very lean side for much of the West Coast and parts of the Southwest. Water worries were foremost on the minds of Californians, for whom the impact count for April reached 68 Nevada and Texas saw 11 and 9 impacts, respectively, also with water restrictions and supplies in the forefront.  Overall, 102 impacts were recorded in the Drought Impact Reporter in April 2015.

California’s persistent drought squeezing water supplies

The California State Water Resources Control Board approved a statewide emergency regulation on May 5, demanding an immediate 25 percent cut in overall potable urban water use as ordered by Gov. Jerry Brown on April 1. If these regulations receive approval from the Office of Administrative Law, they will take effect June 1.

The board deemed the emergency regulations necessary after the public’s poor conservation efforts reached 9 percent and remained far short of the governor’s call for 20 percent voluntary conservation requested in January 2014. In March 2015, urban water use dipped by less than 4 percent, compared to March 2013. Conservation levels from previous months were less than 22 percent in December, 7.3 percent in January and 2.8 percent in February.

“This is the drought of the century, with greater impact than anything our parents and grandparents experienced, and we have to act accordingly,” said Felicia Marcus, chair of the State Water Resources Control Board. “Today we set a high but achievable bar, with the goal of stretching urban California’s water supply. We have to face the reality that this drought may continue and prepare as if that’s the case. If it rains and snows next winter, we celebrate. If the drought continues, we’ll be glad we took difficult but prudent action today. It’s the responsible thing to do.”

The State Water Board previously issued mandatory targets for water conservation, but water agencies balked, saying the targets were unrealistic. On April 17, the board came back with revised targets.

“State Water Board Adopts 25 Percent Mandatory Water Conservation Regulation,” California State Water Resources Control Board, May 5, 2015
“California water conservation effort failing badly,” by John Bacon, USA Today, May 5, 2015
California Sets Water Use Targets Amid Record Low Savings,” by Associated Press, The New York Times, April 7, 2015
State water board issues revised drought regulations for Californians,” by Bettina Boxall, Matt Stevens and Monte Morin, Los Angeles Times, April 19, 2015

California curtails junior water rights, alerts senor rights holders

The State Water Resources Control Board notified junior water rights holders in the Sacramento River Watershed, the San Joaquin River Watershed and other watersheds that their diversions must end to leave sufficient water for senior water rights holders. Even senior riparian and pre-1914 rights holders were cautioned that, for the first time, they may also receive curtailment notices this summer, with the first of such notices expected to be issued in mid-May.

Californians with Century-Old Water Rights Face Restrictions,” by Fenit Nirappil, Associated Press, San Jose Mercury News (Calif.), April 3, 2015
Notices Of Water Availability (Curtailment And Emergency Regulations), California State Water Resources Board, May 1

Tiered water rates ruled illegal, previously a key feature of Gov.’s conservation order

While the governor urged water agencies to use tiered water rates as a means to promote water savings, the 4th District Court of Appeals ruled that San Juan Capistrano’s tiered water rate system was illegal, sounding a warning for water districts statewide that use tiered pricing to discourage water waste. A voter-approved law says that government fees must be comparable with service costs. Tiered rates charge customers more for using more water. Those who sued the city said that higher rates needed to be associated with service costs, such as conservation programs, rather than arbitrarily assigned.

Court: San Juan Capistrano's tiered water rates are illegal, may hinder conservation,” by Meghann M. Cuniff, The Orange County Register (Santa Ana, Calif.), April 20, 2015

California implementing standards for water-efficient faucets and urinals in 2016

The California Energy Commission was stepping up the development of water-efficiency standards for faucets and urinals. The new standards will become effective in January 2016, and devices that do not meet the standards will not be sold in 2016.

California speeds water-efficiency standards for faucets,” by Fenit Nirappil, Associated Press, Monterey Herald (Calif.), April 9

Advice in historically dangerous fire conditions: “Don’t do anything stupid”

Wildfire activity was above normal for the first four months of 2015 with Cal Fire battling 1,100 fires, a sizeable increase over the average 650 fires for that time frame. The number of acres burned was slightly below average, as firefighters remained on alert to address small fires before they become large.

Cal Fire Chief Ken Pimlott stated that conditions this year were the worst on record.

Along California’s central and southern coasts, fire agencies have upped staffing levels ahead of schedule, due to the exceedingly dry landscape after years of drought. Depleted water resources previously tapped by helicopters for firefighting were, in some cases, too low to be useful, prompting Cal Fire crews to use inflatable pools for refilling. To reduce the likelihood of fires, Californians were urged to be very careful with fire and to pull out all grass and brush allowed to go dormant.

“Don’t do anything stupid; we have to reiterate that, that is the message: Don’t do anything stupid,” said John Laird with the California Department of Natural Resources.

Cal Fire Reports Worst Fire Conditions on Record This Season,” by KGO 810am (San Francisco), May 5, 2015
Cal Fire incident information
Fire crews in California increase staffing earlier,” Associated Press, (San Francisco Chronicle), April 13, 2015
CAL FIRE Closely Monitoring Water Levels,” by Katie Orr, Capital Public Radio (Sacramento), April 13, 2015
‘Don’t Do Anything Stupid’ — Fire Officials Send Strong Message During California Drought,” by Ian Schwartz, CBS Sacramento, May 4, 2015

Crops in flux; water scarcity intensifies urban-ag conflict

The agricultural sector has suffered significantly amid drought as farmers fallow fields, adjust crop plans, find alternate irrigation water and cope the best they can to remain afloat. Lucrative fruit and nut trees have become farmers’ favorite crops and have replaced thirstier crops, such as rice, broccoli, carrots, tomatoes and cotton. Irrigation water for agriculture was not affected by the governor’s mandate for 25 percent cuts in water use or in the State Water Board’s water targets, leaving water agencies and other groups feeling that farmers were not bearing the same burden of water cuts that others were. However, the State Water Project offered just 20 percent of normal allotments, while the federal Central Valley Project said that most Central Valley farmers would get no water for the second year running. Farmers, and almond growers in particular, defended themselves, asserting that they have been implementing water-efficient technologies and practices wherever possible.

Calif. drought challenges state's businesses,” by Elizabeth Weise and Doyle Rice, USA Today, April 4, 2015
Almond board to drought-weary Californians: We're not wasting water,” by Matt Stevens, Los Angeles Times, April 14, 2015
Farm water use comes under scrutiny,” by Jesse Marx and Ian James, The Desert Sun (Palm Springs, Calif.), April 20, 2015
More fallowing expected as rice planting gets underway,” by Ching Lee, California Farm Bureau Federation, Chico Enterprise Record (Calif.), April 29, 2015
“California officials to supply just 20 percent of water,” by Scott Smith, Napa Valley Register (Calif.), March 2, 2015
“As California Drought Enters 4th Year, Conservation Efforts and Worries Increase,”
 by Adam Nagourney, The New York Times, March 17, 2015

Farmers sinking more new wells; land subsidence continues

Amid persistent drought and low water allocations, Central Valley farmers continued to over-pump groundwater to irrigate crops, further depleting groundwater stores, which were critically endangered even before the drought began. Some areas have seen drops of 50 feet or more in their water tables in a few years, with alarming and permanent land subsidence causing structural damage to canals, roads and bridges. Farmers’ desperate demand for new wells has led some to pay out-of-state drillers two to three times the cost just to sink the wells sooner than local drillers can, due to the backlog in work requests.

Beneath California Crops, Groundwater Crisis Grows,” by Justin Gillis and Matt Richtel, The New York Times, April 5, 2015
California’s Central Valley Sinking Faster Than Ever Before As Farmers Drill For Water During Drought,” by Allen Martin, CBS San Francisco, April 26, 2015

California’s salmon, smelt populations struggling

The California Department of Fish and Wildlife closed a 5.5 mile stretch of the Sacramento River to salmon fishing from April 27 through July 31. The California Fish and Game Commission proposed the closure to guard critical spawning habitat and eliminate stress and hooking deaths of winter-run salmon. Winter-run Chinook salmon spawn there and largely perished in 2014 when only 5 percent survived.

Further south, the March trawl survey for adult smelt conducted by the DWF found only four females and two males in the Sacramento-San Joaquin Delta. The April survey turned up just one fish. Counts of longfin smelt have also fallen to record lows. Early in April, the State Water Resources Control Board chose to limit Sierra runoff to the estuary, due to drought, depriving fish of the cold, fresh water that enhances survival.

Part of Sacramento River closed to salmon fishing,” by Associated Press, Napa Valley Register (Calif.), April 28, 2015
Fishing Ban Proposed On Stretch Of Sacramento River,” by Amy Quinton, Capital Public Radio (Sacramento), April 6, 2015
“California drought: Delta smelt survey finds a single fish, heightening debate over water supply,” by Lisa M. Krieger, San Jose Mercury News, April 19, 2015

Yosemite National Park roads, trail open early

Sparse snowfall in Yosemite National Park and early snow melt allowed Glacier Point Road, Tioga Road and Half Dome trail to open weeks ahead of schedule. Snow and ice normally impede travel into May.

Yosemite's Half Dome opens three weeks early because of California's drought,” by Joseph Serna, Los Angeles Times, April 30, 2015
“Another early opening for Tioga Road, Yosemite's major east-west route,”
by Mary Forgione, Los Angeles Times, May 4, 2015

Lake Tahoe to have fewer open boat ramps

Lake Tahoe, having been below its natural rim since October 2014, will have fewer boat ramps open during the summer of 2015. The ramps that are likely to remain closed the entire summer include the popular Sand Harbor ramp, just south of Incline Village; Coon Street on the north shore at Kings Beach, California, and on the south shore at El Dorado Beach and Tahoe Vista, California. The summer boating season typically begins on May 1.

Sierra drought keeping several Lake Tahoe boat ramps closed,” Associated Press, San Diego Union-Tribune, April 15

Iconic Lake Tahoe trout relocated

Twenty-six brown trout and four rainbow trout in Lake Tahoe beneath Fanny Bridge were relocated to a marina in Homewood, which is a more suitable site with higher dissolved oxygen levels than the Fanny Bridge area. California Department of Fish and Wildlife staff had been monitoring the water quality and dissolved oxygen level in the stagnant water at Fanny Bridge.

Amid low oxygen levels, Lake Tahoe trout relocation goes swimmingly,” Tahoe Daily Tribune (Nev.), April 23

Nevada establishes Drought Forum

Drought preparations in Nevada included the creation of the Nevada Drought Forum to assess the persistent drought and advise on state policies. The Senate Finance Committee was urged to restore funding for the Nevada’s cloud seeding program to enhance the state’s water supply. This winter was the state’s driest on record, and northern Nevada was in its fourth year of drought.

Sandoval creates drought panel, says Nevada much better off than California,” by Sandra Chereb, Las Vegas Review-Journal, April 9, 2015
Nevada legislators urged to restart cloud seeding amid drought,” by Sandra Chereb, Las Vegas Review-Journal, April 2, 2015

Lake Mead falls to historic low

The level of Lake Mead dipped below 1,080.19 feet above sea level at the end of April, falling to a level not seen since May 1937 when the lake was filling. The April forecast for the Colorado River predicted roughly 52 percent of average flow this summer for the 40 million people who rely on the river for water and electricity, and one expert warned that the flow could be even less.

The Southern Nevada Water Authority was hurriedly designing and constructing a deep water intake and an associated pumping station to continue drawing water even if the water level falls another 185 feet to the dead pool, at which point the Hoover Dam cannot release water. The cost of the water authority’s new intake pipe and pumping station could exceed $1.4 billion.

Savage drought will drive Lake Mead to record low on Sunday,” by Henry Brean, Las Vegas Review-Journal, April 23, 2015

Oregon water supply tight for farmers, wildlife refuges

Water supplies were expected to be short in much of southeastern Oregon where the U.S. Department of Agriculture has made drought designations, making growers eligible for low-interest loans. Farmers received notice that water deliveries will be a fraction of the normal allotment and may end early. Local wildlife refuges will get no water in 2015, except for those on lands leased to farmers to grow crops, stated a spokesman for the U.S. Fish and Wildlife Service.

“Feds declare drought emergency in 13 Oregon counties, releasing aid money,” by Kelly House, (Portland), March 20, 2015
Farmers on Oregon-California border might get less water than they expect,” by Jeff Barnard, Associated Press, The Bulletin (Bend, Ore.), April 9, 2015

Supply estimates decline for junior rights holders in Washington

Water supplies were very tight in the Yakima River Basin due to low natural river flows amid intensifying drought and abysmally low snowfall. In March, the allocation for junior water rights holders was 73 percent; in April, it was downgraded to 60 percent, and by the start of May, it was 47 percent and could drop to 38 percent in a worst-case scenario, according to a U.S. Bureau of Reclamation spokesman.

Stored water used early in Yakima Basin drought,” by Associated Press, The Spokesman-Review (Spokane, Wash.), April 22, 2015
“Yakima Basin water supply outlook worsens again,” by Kate Prengaman, Yakima Herald-Republic (Wash.), May 4, 2015

Timing of allocation decisions hurts Idaho farmers

As in much of the West, low snowpack cut into water resources, leaving reservoirs low. Fremont County commissioners declared a drought emergency, based on reservoir storage, snowpack and other water data. Growers in the Boise Project were caught off guard this year when their irrigation allotment was set early and was considerably lower than in 2014. The low allotment left farmers without enough water to grow already-planted crops and no time to adjust cropping plans.

“Fremont declares drought emergency,” by Heather Randall, Standard Journal (Rexburg, Idaho), April 9, 2015
“Facing drought conditions, Treasure Valley farmers juggle how to spread thin water allotments,” by Zach Kyle, Idaho Statesman (Boise), April 22, 2015



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