Drought - April 2002


NCDC transitioned to the nClimDiv dataset on Thursday, March 13, 2014. This was coincident with the release of the February 2014 monthly monitoring report. For details on this transition, please visit our public FTP site and our U.S. Climate Divisional Database site.

National Overview

On the national scale,
  • severe drought affected about 21 percent of the contiguous United States as of the end of April 2002;
  • the coverage of the current (November 1999-present) drought peaked in August 2000 at about 36% of the contiguous U.S., which was as extensive as the major droughts of the last 40 years, but not as large as the "dust bowl" droughts of the 1930's and 1950's;
  • the total drought area decreased to about 10 percent by November 2000, but has shown a general increasing trend for much of the period since then (see graph below left);
  • on a broad scale, the last two decades were characterized by unusual wetness with short periods of extensive droughts, whereas the 1930's and 1950's were characterized by prolonged periods of extensive droughts with little wetness (see graph below right);
  • although various parts of the U.S. have experienced unusually wet conditions during the last 30 months, little change occurred in the aggregate national wetness picture during much of this period;
  • the percentage of the nation severely wet has held steady at about three to eleven percent during this period, only recently falling below one percent (see graph below left);
  • a file containing the national monthly percent area severely dry and wet from 1900 to present is available;
  • historical temperature, precipitation, and Palmer drought data from 1895 to present for climate divisions, states, and regions in the contiguous U.S. are available at the Climate Division: Temperature-Precipitation-Drought Data page in files having names that start with "drd964x" and ending with "txt" (without the quotes).
Click here for graphic showing U.S. Drought and Wet Spell Area, 1996-present
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Click here for graphic showing U.S. Drought and Wet Spell Area, 1900-present
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Although some areas of the U.S. had above normal precipitation, many areas were very dry. Integrated across the nation, April 2002 precipitation averaged slightly below normal. Twelve of the last 32 months have averaged well below the normal, while only three averaged well above normal (see graph top right). National 2001-2002 precipitation ranks:

Period Rank
Apr 39th driest
Mar-Apr 51st wettest
( 58th driest)
Feb-Apr 14th driest
Jan-Apr 12th driest
Dec-Apr 20th driest
Nov-Apr 28th driest
Oct-Apr 27th driest
Sep-Apr 30th driest
Aug-Apr 31st driest
Jul-Apr 31st driest
Jun-Apr 34th driest
May-Apr 34th driest
Click here for graphic showing U.S. Precipitation Departure and Normals, January 1998-present
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Click here for graphic showing U.S. Precipitation, April, 1895-2002
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Regional Overview

Across the western U.S., beneficial precipitation during April continued a gradual amelioration in drought conditions in the Pacific Northwest and parts of the northern Rockies while much of the southwestern U.S., extending from California to the Texas Rio Grande Valley and into the central Rockies, was extremely dry. Beneficial precipitation continued for a second month bringing short-term relief to parts of the Northeast, but conditions this month across the Southeast were parched. Dry conditions continued during April in parts of the Great Plains, associated with a pattern of longer-term dryness (3-month, 6-month) in some areas. April was generally drier than normal across southeast and southern coastal Alaska and at the primary stations in Hawaii, but wetter than average across much of the rest of Alaska. According to the National Weather Service, several records for the driest April and driest Spring were set at stations in the Alaskan panhandle. Snowpack at the end of April showed a mixed pattern across Alaska.

These overall conditions are evident in the following indicators:

Two other drought-related monitoring tools are the Vegetation Health Index and the Keetch-Byram Drought Index:

  • NOAA satellite observations of vegetation health from early May reveal stress on vegetation in parts of the Plains, in the southwestern U.S., and parts of the central Rockies.
  • The Keetch-Byram Drought Index (KBDI) is used by the Wildland Fire Assessment System to monitor the risk of wildfires. The early May KBDI showed dry conditions in the Desert Southwest, along the Rio Grande Valley, parts of the southern and northern Plains, and across Florida to the mid-Atlantic coast. The Forest Service fire danger analysis indicated a high risk of wildfires in the Southwest, across Montana to the adjoining sections of the Dakotas, and in the Upper Mississippi Valley. The fire threat conditions can change rapidly from week to week.


Western U.S. Drought

April continued the precipitation pattern of recent months, with Pacific storms bringing limited drought relief to the Pacific Northwest and northern Rockies while the southern portions of the West continued dry. On a regional basis, the Pacific Northwest had the 29th wettest April in the last 108 years, while April 2002 ranked 35th driest in the West region and 12th driest in the Southwest. Reservoir levels across the West were still generally below-average, reflecting dry conditions in the very long-term (24 months or longer) in some areas and low snowpack this season in others.

The rainy season (October-April) for the West region started out wet, but the last four months have been drier than normal regionwide (see top right graph below). January-April 2002 ranked as the ninth driest January-April on record for the region (see bottom right graph below). The last 12 months ranked as the 17th driest May-April on record for the region.

Precipitation Ranks for the
West Region, 2001-2002
Period Rank
Apr 35th driest
Mar-Apr 21st driest
Feb-Apr 13th driest
Jan-Apr 9th driest
Dec-Apr 19th driest
Nov-Apr 32nd driest
Oct-Apr 31st driest
Sep-Apr 30th driest
Aug-Apr 29th driest
Jul-Apr 30th driest
Jun-Apr 27th driest
May-Apr 17th driest
Click here for graphic showing West Region Precipitation Anomalies, January 1998 - present
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Click here for graphic showing West Region Precipitation, January-April, 1895-2002
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The Southwest region has experienced persistently dry conditions for much of the last eleven months (see top right graph below). Mountain snowpack was essentially gone from the southern portions (Arizona and New Mexico) of the region by the end of April and considerably below average elsewhere in the region. Measurements of snow water equivalent ranged from 25 to 50 percent of average, or less. January-April 2002 ranked as the second driest such year-to-date on record regionwide, and May-April ranked as the third driest such 12-month period. Several other seasons within the last year have ranked as second or third driest (see table below).

Precipitation Ranks for the
Southwest Region, 2001-2002
Period Rank
Apr 12th driest
Mar-Apr 9th driest
Feb-Apr 2nd driest
Jan-Apr 2nd driest
Dec-Apr 2nd driest
Nov-Apr 5th driest
Oct-Apr 3rd driest
Sep-Apr 2nd driest
Aug-Apr 3rd driest
Jul-Apr 3rd driest
Jun-Apr 3rd driest
May-Apr 3rd driest
Click here for graphic showing Southwest Region Precipitation Anomalies, January 1998 - present
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Click here for graphic showing Southwest Region Precipitation, September-April, 1895-2002
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The dry conditions in the western U.S., from the Southwest and across the Rocky Mountain states into the adjoining Great Plains, have had significant impacts. As of the end of April, the Navajo Nation and the governors of Montana, Wyoming, Colorado, and New Mexico have declared their states in a condition of drought disaster or drought emergency or requested this designation from the federal government, and Utah and Nevada are in states of water emergency. Low streamflows, increasing wildfires, and municipal water shortages were common (NY Times). Some highlights:

  • Parts of North Central Montana experienced record drought during 2002
  • Colorado had the driest October-April through March-April on record in 2002
  • Arizona had the driest September-April on record in 2002
  • According to the USDA, as of the beginning of May, the following ten states (all but 2 in the West) had 25% or more of their range and pasture lands in poor to very poor condition:
    NM - 83%, CO - 68%, AZ - 64%, MT - 54%, WY - 42%, TX - 39%, KS - 37%, UT - 35%, CA - 30%, OR - 27%
  • Several years of drought have dried the soil, allowing strong winds to whip up blinding dust storms across several Rocky Mountain and Great Plains states, from Montana to Colorado. A dust storm in western Kansas on April 16 was visible in satellite images.
  • According to the U.S. Forest Service, reports have been received of considerable tree mortality in the Great Basin, indicating long-term drought stress.
  • According to State Climatologist Jan Curtis, Wyoming reservoirs are low, runoff is down and dust storms are more frequent.
  • USDA reports of drought impacts in Arizona include:
    • record low April and January-April streamflow into the reservoir system
    • well below-normal precipitation
    • below-average reservoir storage, with Horseshoe Lake reporting empty
    • reports of cacti dying in some areas
  • The Salt Lake Tribune reported concern over water restrictions in Utah due to a fourth consecutive year of drought
  • According to local National Weather Service reports, some cities in New Mexico are running dangerously low on water supplies
  • Wildfires became a growing problem during April in Colorado
Click here for details discussing drought in Montana
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Click here for details discussing drought in Colorado
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Click here for details discussing precipitation deficits in Arizona
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Central U.S. Drought

April 2002 was unusually dry across parts of South Dakota, Nebraska, Kansas, Oklahoma, and Texas. This month was a continuation of dryness which extended back at least six months for some of these areas.

Click here for map showing Palmer Z Index, April 2002
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Click here for map showing 3-month Standardized Precipitation Index, February-April 2002
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Click here for map showing Statewide Precipitation Ranks, February-April 2002
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Click here for map showing 6-month Standardized Precipitation Index, November 2001-April 2002
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The West North Central region, which consists of the western states Montana and Wyoming and the Great Plains states North and South Dakota and Nebraska, has had five consecutive months of near to below-normal precipitation (see top graph below). Dryness during most of the last nine months has given the region a rank of second driest August-April (see bottom graph below).

Precipitation Ranks for the
West North Central Region, 2001-2002
Period Rank
Apr 34th driest
Mar-Apr 24th driest
Feb-Apr 17th driest
Jan-Apr 9th driest
Dec-Apr 4th driest
Nov-Apr 7th driest
Oct-Apr 9th driest
Sep-Apr 11th driest
Aug-Apr 2nd driest
Jul-Apr 26th driest
Jun-Apr 25th driest
May-Apr 20th driest
Click here for graphic showing West North Central region precipitation departures, January 1998 - April 2002
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Click here for graphic showing West North Central region precipitation, August-April, 1895-2002
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Some highlights of the drought impacts:
  • National Weather Service reports for deep south Texas:
    • The extended drought has dropped lake levels so low that the city of Zapata has been forced to take emergency measures to ensure an adequate water supply.
    • Blowing dust was becoming a problem locally in the Rio Grande Valley.
    • The dryness has been accompanied by excessive heat for this time of year. The Weather Service reported that, from January 1st thru May 7th 2002, the Brownsville office had 24 days with highs in the 90s, 17 of which have been consecutive. This breaks the old record of 20 total days in the 90s from January 1st through May 7th, 1982.
  • El Paso, Texas had no measuraable precipitation during April. The dry run extended into early May, with May 6 marking the 90th consecutive day with no precipitation, setting a new all time record for consecutive days without measurable precipitation.
  • A dust storm in western Kansas on April 16 was visible in satellite images.


Eastern U.S. Drought
A wet April brought short-term drought relief to portions of the Northeast region, but the month was excessively dry across the Southeast. April marked the second consecutive month with above-normal precipitation regionwide for the Northeast (see top right graph below). However, long-term deficits are still severe, with May-April ranking as the sixth driest such 12-month period, and the driest May-April since the 1960's (see bottom right graph below).

Precipitation Ranks for the
Northeast Region, 2001-2002
Period Rank
Apr 35th wettest
( 74th driest)
Mar-Apr 28th wettest
( 81st driest)
Feb-Apr 52nd wettest
( 57th driest)
Jan-Apr 38th driest
Dec-Apr 27th driest
Nov-Apr 11th driest
Oct-Apr 7th driest
Sep-Apr 9th driest
Aug-Apr 6th driest
Jul-Apr 5th driest
Jun-Apr 9th driest
May-Apr 6th driest
Click here for graphic showing Northeast region precipitation departures, January 1998 - April 2002
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Click here for graphic showing Northeast region precipitation, May-April, 1895-2002
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Near-normal precipitation across the Southeast region in January and March (see top right graph below) helped alleviate drought conditions in some areas, but long-term deficits remain. October-April ranked as the fourth driest such period for the region, in spite of the recent moisture, and marked the fourth consecutive dry year (see bottom right graph below).

Precipitation Ranks for the
Southeast Region, 2001-2002
Period Rank
Apr 15th driest
Mar-Apr 36th driest
Feb-Apr 16th driest
Jan-Apr 23rd driest
Dec-Apr 14th driest
Nov-Apr 12th driest
Oct-Apr 4th driest
Sep-Apr 12th driest
Aug-Apr 8th driest
Jul-Apr 9th driest
Jun-Apr 19th driest
May-Apr 20th driest
Click here for graphic showing Southeast region precipitation departures, January 1998 - April 2002
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Click here for graphic showing Southeast region precipitation, October-April, 1895-2002
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Some east coast highlights:

  • In spite of the recent rains, long-term deficits gave New Jersey a rank of driest July-April on record
  • The recent rains were not enough to offset the long-term deficits in Maryland, where October 2001-April 2002 ranked as the driest such period on record
  • In 2002, South Carolina had the driest Palmer Hydrological Drought Index since the 1950s
  • Drought declarations remained in effect for many Northeast counties
  • During April, Rhode Island became the latest Northeast state to enter a drought watch.
  • According to news reports, most states in the Northeast have banned some uses of water and imposed rationing on others
  • At the end of April, Maryland well measurements indicated groundwater was still below average in many areas.
  • The recent rains have helped recharge the reservoir storage supplies of the Delaware River Basin watershed, but aggregate reservoir levels are still well below median and remain in drought categories. The 13,539 square-mile watershed drains portions of New York State, Pennsylvania, New Jersey, and Delaware.
Click here for details on New Jersey drought
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Click here for details on Maryland drought
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Click here for details on South Carolina drought
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Click here to go to Top of Page Additional Contacts:

Damage due to the drought has been summarized by NOAA and the Office of Global Programs in the Climatological Impacts section of the Climate Information Project. Crop impact information can be found at the USDA NASS (National Agricultural Statistics Service) and Weekly Weather and Crop Bulletin pages. Drought statements by local National Weather Service Offices can be found at the NWS Hydrologic Information Center. Drought threat assessments and other information can be found at NOAA's Drought Information Center. Additional drought information can be found at the National Drought Mitigation Center, the USDA's National Agricultural Library, the interim National Drought Council, and the NOAA Paleoclimatology Program. The following states have set up web pages detailing current drought conditions and/or their plans to handle drought emergencies:
Colorado - Delaware - Delaware River Basin (DE-NJ-NY-PA) - Florida Panhandle - Georgia - Hawaii - Idaho - Kentucky - Maine - Maryland - Missouri - Montana-1 - Montana-2 - Nebraska - New Jersey-1 - New Jersey-2 - New Jersey-3 - New Mexico - North Carolina - Oklahoma-1 - Oklahoma-2 - Oklahoma-3 - Oregon-1 - Oregon-2 - Pennsylvania-1 - Pennsylvania-2 - South Carolina - Texas - Vermont - Virginia - Washington - Wyoming

For additional information on current and past wildfire seasons please see the National Interagency Fire Center web site or the U.S. Forest Service Fire and Aviation web site.

NCDC's Drought Recovery Page shows the precipitation required to end or ameliorate droughts and the probability of receiving the required precipitation.

Additional climate monitoring graphics can be found at the Climate Prediction Center's monitoring pages:

Drought conditions on the Canadian prairies can be found at the Agriculture and Agri-Food Canada Drought Watch page.

Citing This Report

NOAA National Climatic Data Center, State of the Climate: Drought for April 2002, published online May 2002, retrieved on October 25, 2014 from http://www.ncdc.noaa.gov/sotc/drought/2002/4.