Thursday, March 22, 2018

National Drought Mitigation Center

September 2015 Drought and Impact Summary

Drought maintains grip on West, expands in South, eases in Southeast


By Brian Fuchs, NDMC Climatologist


Drought expanded in September, mainly in the southern Plains and New England. Moderate Drought (D1) expanded from 30.43 to 31.36 percent of the contiguous United States, severe drought (D2) increased from 18.72 to 20.09 percent, extreme drought (D3) increased from 10.71 to 11.45 percent and exceptional drought (D4) stayed the same, affecting 3.00 percent of the area. Last year at this time, drought conditions were similar, with 30.57 percent of the contiguous U.S. in drought. Currently, approximately 112.3 million people are in areas affected by drought, compared to approximately 100.6 million people last month.

Drought Outlook

Drought conditions will continue over the western United States with little change expected by the end of October. The drought conditions from the southern Plains into the Southeast will improve and disappear in some areas, but other areas of drought will remain. Drought in the Northeast is expected to improve, while drought in Puerto Rico will persist.


September temperatures were warmer than normal over most of the United States, especially in the central Plains and upper Midwest, where it was 6-9 degrees warmer than normal. Temperatures about 3 degrees cooler than normal were observed over the Pacific Northwest and portions of Georgia and northern Florida. According to the data from the National Centers for Environmental Information (NCEI), 2015 marked the warmest September in 121 years of record keeping for Minnesota, Wisconsin, Michigan, Maine, Rhode Island, Connecticut, Utah, Colorado and New Mexico.


Dry conditions dominated much of the South in September, where many locations were 3-4 inches drier than normal. Areas of above-normal precipitation were spotty but included much of Nebraska, Iowa, Virginia, South Carolina, south Florida, Wisconsin, southern Arizona, Idaho, and portions of southern New England.

Regional Overviews

Movers & Shakers for September 2015

Percent area
Sept. 1, 2015
Percent area
Sept. 29, 2015
Status Percentage point change

Biggest increases in drought

42.41 moderate 27.92
4.45 16.89 severe 12.44
0.00 4.64 extreme 4.64
Connecticut 21.06 88.01 moderate 66.95
Kansas 0.00 4.48 moderate 4.48
Kentucky 0.00 9.17 moderate
Louisiana 10.98 45.44 severe 34.46
0.00 15.22 extreme 15.22
Massachusetts 0.00 30.43 moderate 30.43
Mississippi 24.70 56.71 moderate 32.01
11.82 31.08 severe
0.00 6.55 extreme 6.55
New Hampshire
7.91 20.42 moderate 12.51
New Jersey
17.03 42.93 moderate 25.90
New York
1.99 5.18 moderate 3.19
Oklahoma 8.84 16.79 moderate 7.95
2.83 6.37 severe 3.54
Rhode Island
17.32 52.33 moderate 35.01
Texas 24.76 38.32 moderate 13.56
9.99 17.55 severe 7.56
1.32 6.27 extreme 4.95
Biggest improvements in drought
11.16 4.86 moderate 6.30
Alaska 17.75 3.58 moderate 17.17
Arizona 70.79 62.60 moderate 8.19
Florida 20.82 4.00 moderate 16.82
6.75 0.00 severe 6.75
Georgia 27.05 17.71 moderate 9.34
Hawaii 24.14 0.00 moderate 24.14
Idaho 91.93 85.59 moderate 6.34
Louisiana 80.73 71.14 moderate 9.59
New Mexico
13.08 7.94 moderate 5.14
North Carolina
33.70 17.66 moderate 16.04
Puerto Rico
63.82 45.14 moderate 18.67
44.96 38.44 severe 6.52
24.89 14.74 extreme 10.15
South Carolina
63.98 31.76 moderate 32.22
26.73 10.91 severe 15.82


Most of the Northeast was as much as 6-8 degrees warmer than normal in September.  Precipitation was mixed, with most areas slightly wetter than normal. The wettest areas were in western Pennsylvania, which had 3-4 inches more than normal precipitation. The warm temperatures led to expansion of drought, with 9.00 percent of the region in drought as of Sept. 29, compared to 3.26 percent at the beginning of the month.


Most of the Southeast was 2-3 degrees warmer than normal in September, although temperatures were 1-2 degrees cooler than normal in southern Georgia and northern Florida. Precipitation was greatest over southern Florida, western North Carolina, South Carolina and the Florida Panhandle, which got up to 3-4 inches more rain than usual, enough to improve drought in those areas. At the end of September, 11.73 percent of the region was in drought compared to 24.32 at the beginning of the month. Severe drought also improved from 5.22 to 1.74 percent of the region and extreme drought was removed from southern Florida.


The Midwest was dominated by above-normal temperatures in September, especially in the upper Midwest, which was 6-8 degrees warmer than normal. Precipitation was mixed, with areas of Iowa, Illinois, Wisconsin and Ohio recording 2-3 inches more rain than usual, while most of Missouri, Indiana, Kentucky, and Minnesota were drier than normal. Drought remained quiet in the region, with only 1.04 percent affected, mainly in Wisconsin and Kentucky.

High Plains

Much of the High Plains was 6-8 degrees warmer than normal in September. Wet conditions along the southern reaches of the Missouri River Basin brought flooding rains to some locations, with some areas recording 5-6 inches more rain than usual. Slightly dry conditions dominated most of Kansas and the Dakotas, with departures of 1-2 inches below normal precipitation common. Even with the heat and dryness of September, only 0.82 percent of the region was in drought at the end of the month.


Temperatures as much as 4-7 degrees warmer than usual dominated the South in September. Most of the region was dry as well, with departures of 3-4 inches below normal common and the largest departures over southern Arkansas and northern Louisiana. Drought expanded in September from 24.61 to 37.43 percent of the area. Severe drought increased from 7.93 to 18.31 percent and extreme drought increased from 0.67 to 5.72 percent of the region.


The West was warmer than normal in September by 3-4 degrees in most areas. The Pacific Northwest was the exception, with temperatures 2-3 degrees cooler than normal. Precipitation was variable, with areas such as western Montana, southern Idaho, southern California, southern Arizona, and northwest Washington receiving 1-2 inches more than normal precipitation. The precipitation brought slight improvement to drought in the West, with 57.81 percent in drought at the end of September compared to 59.67 percent at the beginning of September. 

California facing wildfire and water shortages; incipient Eastern drought eradicated by recent rains

The graphs above describe what's in the Drought Impact Reporter for September 2015. The pie chart shows that Water Supply and government response were among the most frequently chosen categories of impacts. The bar chart shows that California had the most impacts, compared with other states.
Above, the Drought Impact Reporter map for September 2015. Impacts are added continuously.
Above, California's major reservoirs are below historic averages.
The Northern Sierra Precipitation 8-Station Index and the San Joaquin Precipitation 5-Station Index are key means of tracking California's water supply. California's water year ended on Sept. 30 and delivered 37.2 percent of average in the northern Sierra and 15.4 percent of average in the San Joaquin region, well below the 1961-2010 averages.
The map and chart above are from California's new Household Water Supply Shortage Reporting System.

By Denise Gutzmer, NDMC Drought Impact Specialist

September was a tumultuous month for the West, with more than 60 large wildfires burning in California, Oregon, Washington, Idaho and western Montana, although the wildfire activity slowed as the month progressed. California continued to see the most drought impacts, with 65, as the state endured its fourth year of drought and strove to curb water use. North Carolina and Texas each had 17 impacts and New Jersey had 16 impacts.

Active Fire Mapping Program for Sept. 1, 2015

El Niño to the rescue?

The September El Niño forecast issued by the National Weather Service’s Climate Prediction Center noted that computer models unanimously pointed toward a strong El Niño with a 95 percent chance of the event lasting through the winter. If the El Niño does deliver as expected, the southern tier of the U.S., including California, will likely receive more precipitation than normal, easing drought conditions.

“New forecast says El Niño could help Northern California, ease drought,” by Dale Kasler and Phillip Reese, The Sacramento Bee (Calif.), Oct. 8,, 2015

A monster El Niño is likely, but there are 'no guarantees,'” by Rong-Gong Lin II, Los Angeles Times, Sept. 10, 2015

California wildfires sear landscape

Heavy wildfire activity in California continued in September, as it has through much of 2015, with the California Department of Forestry and Fire Protection fighting 42 percent more fires than the five-year average. Those blazes burned nearly three times as much land as the five-year average (see table).

Two of the largest wildfires in California’s history—the Valley and Rough fires—began in early September, blackened nearly 147,000 acres and took the lives of at least five people. The Valley fire became the third largest fire in the state’s history, destroying 1,280 homes, while the Rough fire became the seventh largest fire in California history and destroyed 475 homes.

Interval Fires Acres
Jan. 1-Oct. 3, 2015 5,635 305,958
Jan. 1-Oct. 3, 2014 3,885 190,246
Five-year average 3,967 107,452

Statistics include all wildfires responded by CAL FIRE in both the State Responsibility Area, as well as the Local Responsibility Area under contract with the department, plus all large wildfires in State Responsibility Area protected by CAL FIRE’s contract counties.

Valley Fire Incident Information, Cal Fire, Oct. 6, 2015

Butte Fire Incident Information, Cal Fire, Oct. 1, 2015

California wildfires harm air quality

Air quality in the San Joaquin Valley has been poor throughout the drought, due to the lack of rain to wash particles from the air and dust from unplanted fields and newly dug wells.  Smoke from recent fires has worsened air quality significantly, causing problems even for healthy people. Asthma has become a much bigger problem in the valley since the start of the drought.

Fires in West Have Residents Gasping on the Soot Left Behind,” by Ian Lovett and Jennifer Medina, The New York Times, Sept. 9, 2015

California exceeded water conservation target in August

In August, Californians conserved 27 percent, compared to the same month in 2013, exceeding the governor’s mandate for 25 percent water conservation. Meanwhile, many communities met their individual water conservation targets, ranging up to 36 percent, with the exception of some small communities that host large food processors and cannot meet their targets unless the processors slash production or jobs, which would harm the economy of the small towns. The city of Livingston won an alternative compliance order from the state, and other cities were pursuing similar options.

“Drought: Californians meet water target — again — with 27% cut,” by Kurtis Alexander, San Francisco Chronicle, Oct. 1, 2015

“Small cities find California water-conservation mandates hard to meet,” by Marc Benjamin, The Fresno Bee (Calif.), Sept. 7, 2015

New system monitors dry wells in California

The State of California has created a Household Water Supply Shortage Reporting System to document the number of dry wells and other water supplies existing in the state. As of Oct. 1, there have been 2,857 reported household water shortages and 565 resolved shortages since January 2014, for a difference of 2,292 ongoing household water shortages in California.

“Growing number of wells run dry due to Calif. Drought,” by Kelli Saam, KRCR TV (Redding, Calif.), Sept. 2, 2015

East Coast locales entered drought watch status in September

Along the East Coast from Maine to South Carolina, cities restricted water use in September because rainfall had been below normal. The Upper Savannah River Basin in Georgia entered Drought Level 1, and the Yadkin-Pee Dee Basin in North and South Carolina entered a drought watch stage. Drought watches were issued for parts of Virginia and New Jersey. In Connecticut, the Department of Public Health urged water conservation and a water provider followed suit by requesting water conservation. Heavy rainfall along the East Coast in early October replenished many water stores.

 “Thurmond Lake enters drought status despite wet August,” by Wesley Brown, The Augusta Chronicle (Ga.), Sept. 8, 2015

 “Roanoke Valley, Southside Virginia under drought watch issued Tuesday,” by Rex Springston, The Roanoke Times (Va.), Sept. 15, 2015

 “Yadkin-Pee Dee River Basin enters drought watch stage,” (Lexington, N.C.), Sept. 21, 2015

 “Drought watch issued for 12 counties, 6 million people as N.J. water worries worsen,” by Stephen Stirling, Trenton Times (N.J.), Sept. 23, 2015

 “Aquarion urges residents to conserve water due to drought,” Danbury News-Times (Conn.), Sept. 24, 2015

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