Backgrounder: Hurricanes in 2005

By all accounts the 2005 Atlantic hurricane season was an historic event. From the time that Tropical Storm Arlene first formed in June to the demise of Tropical Storm Zeta, which survived into 2006, the record-breaking 2005 season was defined by an unprecedented 31 tropical depressions, 28 named storms, and 15 hurricanes. In total, at least a dozen meaningful records of activity, intensity, or impact, were broken:

• Latest end of hurricane season: Jan 6 (previous – Jan 5 in 1954/5)
• Most named storms: 28 (previous - 21 in 1933)
• Most hurricanes: 15 (previous - 12 in 1969)
• Most Category 5 hurricanes: 4 (previous - 2 in 1960 & 1961)
• Most intense hurricanes to strike theU.S.: 4 (previous - 3 in 1893, 1909, 1933, 1954, 2004)
• Most named storms before July: 5
• Most major hurricanes forming in July: 2
• Most named storms forming in November: 3
• Most intense hurricane: Wilma – 882 mb (previous – 888 mb in Gilbert in 1988)
• Greatest surge from hurricane: 28-30 ft from Katrina in Gulfport, Miss. (previous 24.6 ft - Camille 1969)
• Most number of names retired from one season (Dennis – Katrina – Rita – Stan – Wilma)
• Total damage: $100 USD billion
• The farthest east and north that a tropical cyclones has ever formed (Vince) . . . and the first to strike the Iberian Peninsula

Many blamed the very warm water temperatures and the weak upper atmospheric winds in the tropical Atlanticon the proliferation.  Seasonal hurricane forecasting is a challenging science which considers a number of atmospheric and oceanic indicators such as: current and future tropical ocean temperatures and trade winds; past winter ocean temperatures northwest of Europe; previous fall sea level pressures in the Gulf of Mexico; and past winter upper atmospheric winds over east Brazil and the South Indian Ocean.

In 1995 the Atlantic erupted with hurricane activity, and meteorologists recognized that a long-term trend of warmer ocean temperatures had already become established. If not for the effects of a lengthy El Nino period from1992–1994 (a known hurricane inhibitor) keeping hurricanes at bay, tropical cyclone production would have stepped up even sooner.

For more information, please contact:
Peter Bowyer
Manager,
Canadian Hurricane Centre,Environment Canada
(902) 426-9181