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Precipitation was below average for the conterminous United States in 2001. The estimated January-December anomaly was 0.7 inches (18 mm) below the long term mean. This value could change based on conditions in December. This year marked the third consecutive year of below normal precipitation, following nine years of precipitation surpluses. |
| It is estimated that Maine will have the driest year on record for 2001, depending upon conditions in December. For the period January through November 2001, most east coast states and a few western states had precipitation deficits placing them in the bottom third portion of the historical distribution. This year could be among the ten driest years ever for many of these states. In contrast, some states from the upper Midwest southward along the Mississippi River Valley generally received above normal precipitation, most notably Michigan. |  larger image |
Drought and Wildfires
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On a national scale, long-term drought (as measured by the Palmer Drought Index) gradually expanded from about 15% of the country in the severe to extreme categories in January to a peak of 20% in October 2001. A series of Pacific storms brought rain and snow to much of the western drought areas beginning late autumn, resulting in a decrease in the drought area to about 16% of the contiguous U.S. by the end of November. |
The percent of the country in the severe to extreme wet spell categories (as measured by the Palmer Drought Index) peaked early in the year at about 11% in February but gradually decreased to about 4% of the country by the end of the year.
| The 2001 national drought had its origins in late 1999. At its peak in August 2000 this drought, when compared to other droughts of the 20th Century, 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 duration of the current national drought (about 25 months) falls in between the duration of the 1970's and late 1980's droughts. | 
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At its widest expanse in 2001, drought affected about 20% of the contiguous U.S. The areas most severely affected included parts of the southern Great Plains, much of the western U.S. and, by November, much of the eastern seaboard. |
| Extremely dry conditions during November through March (see graph below right) resulted in the second driest rainy season in the last 107 years for the Pacific Northwest. Only 1976-77 was drier. Many rivers reached record low streamflow levels and reservoirs were depleted to meet water demand. Three states (Washington, Oregon, and Idaho) declared drought emergencies. A series of Pacific storms near the end of autumn brought a beneficial snowpack to the mountains and a wet start to the 2001-2002 rainy season (see graph below left). |
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The combination of hot, dry, windy conditions and high-altitude dry thunderstorms sparked thousands of new wildfires in August. During the first 20 days of of the month, about 1.23 million acres were blackened in the Great Basin, Pacific Northwest, and northern California, increasing the national year-to-date total to 2.83 million acres (103% of the 10-year average). |
| The eastern seaboard, from Georgia to Maine, experienced very dry conditions during 2001. The drought resulted in record low streamflows, low or dry wells, low reservoirs, and severe stress on crops. Several states declared statewide burning bans, drought alerts were announced for numerous counties, and several communities implemented water use restrictions. The very dry conditions during October led to hundreds of small wildfires in many eastern states from Kentucky and Virginia to South Carolina, and also in Massachusetts. |
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| In the Northeast region, eight of the months from January to November were drier to much drier than normal, but the drought can be traced back to late summer 2000 (see graph below left). Wet conditions interrupted the drought during March and June. Nevertheless, 2001 had the third driest April and April-November in the last 107 years (see graph below right), fourth driest October-November, and seventh driest January-November. Record or near-record low streamflows and groundwater in Maine raised the concerns of power companies, water utilities, and homeowners with shallow wells. In 2001, Maine had a record driest May-November and January-November. By early November, Upper Delaware Basin reservoir storage declined to drought warning levels, triggering reductions in Delaware River flow targets and water diversions to New York City and New Jersey. According to the USGS in Baltimore, Maryland, low rainfall and warm temperatures in November contributed to record low streamflow and ground-water levels. Streamflow into the Chesapeake Bay was the lowest for November since records began in 1937, and just below the previous record set in 1964. |
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Parts of the Southeast have suffered from drought for much of the last 4 years (see graph below left). In 2001, seven of the months from January to November were drier or much drier than normal. Heavy rains brought drought relief to the region in March, and much of the Gulf coast got a summer reprieve beginning in June with copious rainfall from Tropical Storm Allison. But dry conditions returned with a vengeance in October, giving the region the sixth driest October-November on record. January-November 2001 ranked as the 25th driest (see graph below right). Drought was blamed as the cause for one of the worst shrimping seasons on record in Georgia, and water restrictions were implemented in some Georgia cities by September. South Carolina Forestry officials reported that January 2001 had more wildfire activity than any January in the last 15 years. In February, the Governor of Mississippi issued a ban on all outdoor open burning because of concerns over a recent rash of wildfires. Dry conditions and abundant fuel in the form of fallen leaves set the stage by mid-November for the worst wildfire season in a decade in the Appalachian mountain region. |
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The year started dry for Florida, continuing a drought that had begun nearly four years earlier. Hydrological impacts included reduced streamflow, lake, and groundwater levels. Over 3100 wildfires burned more than 335,300 acres (135,700 hectares) during the first five months of the year, including a fire that closed a 17-mile section of Interstate 4, a heavily traveled route between Orlando and Tampa. Lake Okeechobee dropped to record low levels by early March. In response to the worst drought conditions since the 1930's, emergency mandatory water-use restrictions were in effect in many Florida communities. Relief came in March with heavy rains, but it wasn't until several tropical systems dropped copious rainfall during the summer that much of the state was pulled out of drought. |
Severe Storms
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There were 8 very strong to violent tornadoes (wind speeds in excess of 158 mph, category F3-F5) during the 2001 tornado season (March-August). This is well below the long-term (1950-2000) mean of 38 and is the lowest such tornado count in the last 51 years. The previous record was nine violent tornadoes in 1987. Little trend in very strong to violent tornadoes has been observed since 1950. |
| There were 15 named tropical storms in 2001, nine of which became hurricanes with four reaching major hurricane strength. On average, between nine and ten named storms form with six growing to hurricane strength and two developing into major hurricanes. A tendency for greater hurricane activity has occurred over the past six years after more than two decades of generally below-average activity. | 
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| Five or more major hurricanes occurred three times in the 90's; 1995, 1996 and 1999. (A major hurricane is defined as category 3 or higher according to the Saffir-Simpson scale. A category 3 hurricane has winds 111-130 mph). Prior to 1995, five or more major Atlantic hurricanes had not occurred in one season since 1964. A new record number of hurricanes for November was set in 2001 as Michelle, Noel and Olga all were active in the Atlantic Basin during the month. The contiguous U.S. has not been hit directly by a hurricane now for the past two years, although tropical storms have caused significant damage, as evidenced by Tropcial Storm Allison. This storm, the costliest tropical storm on record ($5 billion in damage), caused severe flooding in Texas and Louisiana before moving across the Southeast and up the East Coast. |
For further information, contact:
Jay Lawrimore
NOAA/National Climatic Data Center
151 Patton Avenue
Asheville, NC 28801-5001
fax: 828-271-4328
email: Jay.Lawrimore@noaa.gov
-or-
Richard Heim
NOAA/National Climatic Data Center
151 Patton Avenue
Asheville, NC 28801-5001
fax: 828-271-4328
email: Richard.Heim@noaa.gov
-or-
Dimitri Chappas
NOAA/National Climatic Data Center
151 Patton Avenue
Asheville, NC 28801-5001
fax: 828-271-4328
email: Dimitri.Chappas@noaa.gov
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