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NOAA satellite image of Hurricane Katrina taken on Aug. 28, 2005, at 11:45 a.m. EDT, as the powerful storm churned in the Gulf of Mexico as a Category Five storm with sustained winds near 175 mph, a day before the storm made landfall on the U.S. Gulf Coast.Sept. 15, 2005 The June-August summer season was the tenth warmest on record for the contiguous U.S., while precipitation was above average. Global temperatures were second highest on record for the boreal summer, which runs from June 1 through August 31. Twelve named tropical systems formed in the Atlantic by the end of August, including Hurricane Katrina, which was among the strongest hurricanes ever to strike the U.S., according to scientists at the NOAA National Climatic Data Center in Asheville, N.C. (Click NOAA satellite image for larger view of Hurricane Katrina taken on Aug. 28, 2005, at 11:45 a.m. EDT, as the powerful storm churned in the Gulf of Mexico as a Category Five storm with sustained winds near 175 mph, a day before the storm made landfall on the U.S. Gulf Coast. Click here for high resolution version. Please credit “NOAA.”)


  • Although Katrina will be recorded as the most destructive storm in terms of economic losses, it will likely not exceed the human losses in storms such as the Galveston Hurricane of 1900, which killed as many as 6,000-12,000 people, and led to almost complete destruction of coastal Galveston.
  • Hurricane Andrew, in 1992, cost approximately $21 billion in insured losses (in today's dollars), whereas estimates from the insurance industry as of Sept. 15, 2005, have reached approximately $60 billion in insured losses from Katrina. The storm could cost the Gulf Coast states as much as an additional $120 billion.

U.S. Temperature:
NOAA scientists report that the average temperature for the contiguous U.S. for the June-August summer season (based on preliminary data) was 1.2 degrees F (0.7 degrees C) above the 1895-2004 mean. This was the tenth warmest summer on record, with each state experiencing either near average or above average temperatures. Much above-average temperatures stretched from Missouri and Iowa to the Northeast and mid-Atlantic. New Jersey had its warmest summer on record, while New York, Vermont and Massachusetts had their second warmest. Statewide temperatures also were much above average in Florida, Louisiana and Nevada.

The anomalous warmth was not confined to the contiguous U.S. New all-time summer records were established in Honolulu and at the airport on Molokai, Hawaii, where the average seasonal temperatures were 83.1 degrees F (28.4 degrees C) and 78.9 degrees F (26.1 degrees C), respectively. The average summer temperature in Alaska was 2.0 degrees F (1.1 degrees C) above average, the third warmest such season on record for the state.

U.S. Precipitation:
Precipitation was above average for the nation overall but with significant regional variability. Wetter-than-average conditions occurred in much of the Southeast and the central Plains states from Oklahoma to North Dakota and Minnesota. Near-average to drier-than-average conditions occurred throughout the West, except California, which had its twelfth wettest summer on record. Unusually dry conditions occurred in parts of the interior Pacific Northwest that continue to be affected by a multi-year drought. Moderate-to-extreme drought also stretched across much of the area from the southern Mississippi Valley to the upper Great Lakes with drought disasters declared in Arkansas, Missouri, Illinois and Wisconsin during the summer. At the end of August, moderate-to-extreme drought (as defined by a widely-used measure of drought—the Palmer Drought Index) affected 16 percent of the U.S.

Dry conditions also contributed to an active western wildfire season. Through the end of August, more than 3.6 million acres had burned in the contiguous U.S. and more than 3.8 million acres in Alaska. The total of 7.4 million acres for the U.S. as a whole is approaching the record of 8.4 million acres, which burned in 2000.

Atlantic Hurricane Season:
The 2005 Atlantic hurricane season began as the most active on record, with four named storms (Arlene, Bret, Cindy and Dennis) by July 5. Twelve named storms formed by the end of August—the eleventh, Hurricane Katrina, became the most destructive hurricane to ever strike the U.S. It first struck southern Florida on August 25 as a Category One storm. It quickly re-intensified once it moved west into the warm Gulf waters, which were 2-3 degrees Fahrenheit (1-2 degrees C) above normal. Katrina continued to strengthen as it turned toward the northwest and eventually north during the next few days.

Katrina's sustained winds reached 175 mph (150 knots) and its minimum central pressure dropped as low as 902 millibars (a measure of a hurricane's strength—the fourth lowest on record for an Atlantic hurricane. The storm's intensity diminished slightly as it approached the central Gulf Coast, but Katrina remained a strong Category Four storm until landfall along the Louisiana and Mississippi coasts on August 29. Although its intensity at landfall was less than that of Hurricane Camille, which devastated coastal Mississippi in August 1969, the size of Katrina, with hurricane force winds extending 120 miles from its center, was much larger and the destruction more widespread than Camille.

The associated storm surge reached as far east as Mobile, Ala., inundating parts of the city. Large parts of Biloxi and Gulfport, Miss., were covered with water as a result of a 20 to 30-plus foot storm surge that reached far inland. The combination of strong winds, heavy rainfall and storm surge led to breaks in the earthen levee system that separates New Orleans from surrounding lakes and canals, leaving large parts of New Orleans under 20 feet of water.

The average global temperature anomaly for combined land and ocean surfaces for the June-August season (based on preliminary data) was 1.1 degrees F (0.6 degrees C) above the 1880-2004 long-term mean. This was the second warmest June-August since 1880 (the beginning of reliable instrumental records). The warmest June-August was in 1998 with an anomaly of 1.2 degrees F (0.7 degrees C) above the mean. Warmer-than-average conditions covered most land areas of the world.

NOAA, an agency of the U.S. Department of Commerce, is dedicated to enhancing economic security and national safety through the prediction and research of weather and climate-related events and providing environmental stewardship of the nation's coastal and marine resources.

Relevant Web Sites
Climate of 2005 - August in Historical Perspective, including Boreal Summer

Climate of 2005 - Summary of Hurricane Katrina

Media Contact:
John Leslie, NOAA Satellites and Information Service, (301) 457-5005