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The unbelievable Hurricane Season of 2005

By: Dr. Jeff Masters, 2:41 PM GMT on December 01, 2005

It is finally December, and hurricane season is officially over. But this is the Hurricane Season of 2005. The normal rules do not apply. True to its character all year, the Hurricane Season of 2005 continues to defy the normal rules. Tropical Storm Epsilon is still out there in the mid-Atlantic, and is expected to be with us another two days before increasing winds shear and cold waters weaken it and convert it to a regular extra-tropical low. The Azores Islands need to be concerned about this storm, but Epsilon is not a threat to any other land areas. Perhaps the last casualty has been inflicted, the last damage done by the Hurricane Season of 2005.

How can one summarize this unbelievable hurricane season? I strongly believe that this was a once-in-a-lifetime hurricane season. To have 26 named storms, 13 hurricanes, and three of the six strongest hurricanes of all time in one year so greatly exceeds our meteorological understanding of what is possible, that I believe that was a once in 500 years kind of season. Let us consider some of the major records that were broken in 2005:

Seasonal records set in 2005

- Most tropical storms: 27. Old record: 21 in 1933.

- Most hurricanes: 14. Old record: 12 in 1969.

- Most Category 5 hurricanes: 3 (Katrina, Rita, Wilma. Emily may be classified as a Category 5 upon re-analysis.) Old record: 2 in 1960 and 1961.

- Most hurricane names to be retired: 6 (Dennis, Emily, Katrina, Rita, Stan, Wilma, and possibly others). Previous record: 4 in 1955, 1995, and 2004.

- Most major hurricanes: 7 (Dennis, Emily, Katrina, Maria, Rita, Wilma, Beta). Ties record of 7 set in 1950.

- Most major hurricanes to hit the U.S.: 4 (Dennis, Katrina, Rita, Wilma). Previous record: 3 in 1893, 1909, 1933, and 1954.

- Most damage ever recorded in a hurricane season: $150 billion. Previous record: approximately $50 billion dollars (normalized to 2005 dollars) set in 1992 and 2004.

-Highest Accumulated Cyclone Energy (ACE) index: 245. Previous record: 243 (1950). Average for a season is 93.

-Latest end to a hurricane season: January 6 Previous record: January 5, for the 1954-55 hurricane season.

Notable near records for the season

- Second highest number of tropical storms to hit U.S.: 7 (The record was 8 in 1916 and 2004). Note that Hurricane Ophelia is not considered a U.S. strike, although it did bring hurricane conditions to the North Carolina coast.

- Second highest number of hurricanes to kill 1000+ people: 2 (Katrina and Stan). All time record: 3 (1780).

- Second highest number of named storm days: 126.5. All time record: 136 (1933).

Single storm records:

- Strongest Atlantic hurricane ever: Wilma, 882 mb central pressure. Old record: Hurricane Gilbert (1988), 888 mb.

- Fastest intensification ever by an Atlantic hurricane: Wilma. Wilma's pressure dropped from 982 millibars to 882 millibars in 24 hours on Oct 19, a rate of 4.2 millibars an hour. Previous record: Gilbert (1988) dropped 3 mb/hour over 24 hours. Wilma's pressure fell 9.7 mb/hour over six hours early on Oct. 19, beating Hurricane Beulah's drop of 6.3 mb/hour in six hours in 1967.

- Most damaging hurricane ever: Katrina, $100 billion plus. Old record: Hurricane Andrew (1992), $50 billion in 2005 dollars.

- Greatest storm surge from an Atlantic hurricane: Katrina, 28-30 feet. Old record: Hurricane Camille (1969), 24.6 feet.

- Dennis became the most intense hurricane on record before August when a central pressure of 930 mb was recorded.

- Emily eclipsed the record previously set by Dennis for lowest pressure recorded for a hurricane before August when its central pressure reached 929 mb.

- Vince was the furthest north and east that a storm has ever developed in the Atlantic basin.

- Vince was the first tropical cyclone in recorded history to strike the Iberian Peninsula.

- Delta was the first tropical cyclone in recorded history to strike the Canary Islands.


Monthly records

June

- Two named storms formed (Arlene and Bret). Only 1957, 1959, 1968, and 1986 had two or more named storms form during the month of June.

July

- Five named storms formed (Cindy, Dennis, Emily, Franklin, and Gert). This is the most on record for July.

- Two major hurricanes formed (Dennis and Emily). This is the most on record.

- 25.25 named storm days occurred. This is the most on record.

- 10.75 hurricane days occurred. This is the most on record.

- 5.75 intense hurricane days occurred. This is the most on record.

August

- Five named storms formed (Harvey, Irene, Jose, Katrina and Lee). Only 1990, 1995 and 2004 had more than five named storms form during the month of August.

September

- Five hurricanes formed (Maria, Nate, Ophelia, Philippe and Rita). This ties 1955, 1969, 1981, 1998 and 2000 for the most hurricanes to form during the month of September.

October

- Six named storms formed (Stan, Tammy, Vince, Wilma, Alpha and Beta). This ties 1950 for the most named storm formations during the month of October.

- Four hurricanes formed (Stan, Vince, Wilma and Beta). Only 1950 had more hurricanes develop during the month of October.

- Two major hurricanes formed (Wilma and Beta). This ties 1950, 1961, 1964 and 1995 for the most intense hurricanes to form during the month of October.

- Five intense hurricane days occurred. Only 1954 and 1961 recorded more intense hurricane days.

November

- Three tropical storms formed in November (Gamma, Delta, and Epsilon). This breaks the record of two storms set in six years, most recently in 2001.

December

- Epsilon was a hurricane for 5.25 days, making it the longest lived December hurricane on record. The previous record was just over four days, set by an unnamed 1887 hurricane.

January

- Tropical Storm Zeta was the longest-lived January storm on record (six days). January 2006 had the greatest number of named storm days ever recorded in January (six).

Earliest Storm Formation records
- Earliest formation of a season's 4th Storm
- Earliest formation of a season's 5th Storm
- Earliest formation of a season's 6th Storm
- Earliest formation of a season's 7th Storm
- Earliest formation of a season's 8th Storm
- Earliest formation of a season's 9th Storm
- Earliest formation of a season's 10th Storm
- Earliest formation of a season's 11th Storm
- Earliest formation of a season's 13th Storm
- Earliest formation of a season's 14th Storm
- Earliest formation of a season's 15th Storm
- Earliest formation of a season's 16th Storm
- Earliest formation of a season's 17th Storm
- Earliest formation of a season's 19th Storm
- Earliest formation of a season's 20th Storm
- Earliest formation of a season's 21st Storm
- Earliest formation of a season's 22nd Storm
- Earliest formation of a season's 23rd Storm
- Earliest formation of a season's 24th Storm
- Earliest formation of a season's 25th Storm
- Earliest formation of a season's 26th Storm

I credit Dr. Bill Gray's Hurricane Season of 2005 Verification posted on his web site for compiling many of these records, along with wunderblogger Cory Pesaturo. You will find many more records listed on their web pages.

Jeff Masters

The views of the author are his/her own and do not necessarily represent the position of The Weather Company or its parent, IBM.