2005 ATLANTIC HURRICANE SEASON STATISTICS

During the 2005 Atlantic hurricane season, a total of thirty-one tropical and subtropical cyclones formed, breaking many records. This article is an in-depth look at the 'statistics of the 2005 Atlantic hurricane season'.

'Related articles'	'2005 Atlantic hurricane season'
	List of storms in the 2005 Atlantic hurricane season
	Timeline of the 2005 Atlantic hurricane season

Contents

Number of storms

Total activity

Statistics

Strongest storms

Rapid formation

Individual storms

Accumulated Cyclone Energy (ACE)

Other records

Notes

References

Number of storms

The 2005 Atlantic hurricane season, with 28 nameable storms (wind speed ≥ 39 mph), is the most active season on record, surpassing the 1933 season's 21 nameable storms. With 15 hurricanes, the 2005 season also has had the most hurricanes formed, surpassing the 1969 season's 12. While the 1950 season still holds the record for the most major hurricanes, eight (2005 had seven), the 2005 season has also tied the 1999 season's record of five Category 4 and 5 hurricanes and holds the record for the most Category 5 hurricanes in a single season, four (see below).

With the formation of Tropical Storm Vince, Tropical Storm Wilma, and Tropical Storm Alpha, 2005 became the first season to use the 'V', 'W' and Greek Letter names, respectively, since naming of Atlantic storms began in the 1950 season. It also has the distinction of being only the second season to use the 'R', 'S', and 'T' names. Only the 1995 season had previously used these letters.
2005 holds the record for the most storms to ever form during the month of July. Five storms (Cindy, Dennis, Emily, Franklin, and Gert) formed during that period. The previous record for most storms to form in the month of July was four; this record was held by the 1966 and 1995 seasons.
The number of storms before the end of July (seven) is also a record, breaking the record of five set in the 1887, 1933, 1936, 1959, 1966, and 1995 seasons.
2005 and 1933 share the record for the most storms (17) forming before the end of September. 2005 now also holds the record for most storms (24) forming before the end of October and for the number of storms (7) forming ''during'' October (Stan, Unnamed Subtropical Storm, Tammy, Vince, Wilma, Alpha and Beta). 1950 was the last year with six storms formed during October. 2005 also broke the record for most storms forming in November, with 3 storms (Gamma, Delta and Epsilon).

Total activity

Tropical activity during the 2005 season was unusually continuous from start to finish, unlike most hurricane seasons, which have significant quiet periods. Out of the 26 weeks in the hurricane season, just two had no tropical cyclones active at some point (the weeks of June 19 and November 6). For a 126 day stretch (June 28-October 31), only 16 didn't have a storm active and never more than three consecutive. There was record or near-record activity in every month of the season except for June.
The 2005 season was the first time since reliable measurements began that the Atlantic basin recorded more tropical storms than the Western Pacific Ocean, which is typically by far the most active basin worldwide.

Statistics

This table gives the number of storms by month of formation and storm category on the Saffir-Simpson Hurricane Scale. The meanings of the one-letter (or number) categories can be ascertained by placing the cursor on that heading.
Entries which are bolded surpassed or tied records established by previous seasons.

Month	# Storms of class								# Storms at least of class
	D	S	1	2	3	4	5		D	S	1	2	3	4	5
Jan-May	0	0	0	0	0	0	0		0	0	0	0	0	0	0
June	0	2	0	0	0	0	0		2	2	0	0	0	0	0
July	0	2	1	0	0	'1'	'1'		5	'5'	'3'	2	'2'	'2'	'1'
August	1	3	0	1	0	0	'1'		6	5	2	2	1	1	'1'
September	1	0	3	0	1	0	1		6	5	5	2	2	1	1
October	1	3	2	0	1	0	'1'		8	'7'	4	2	2	1	'1'
November	0	2	1	0	0	0	0		3	'3'	1	0	0	0	0
December	0	1	0	0	0	0	0		1	1	0	0	0	0	0
Season	3	'13'	7	1	2	1	'4'		'31'	'28'	'15'	8	7	'5'	'4'

Strongest storms

Hurricane Katrina became the fourth most intense Atlantic hurricane on record (currently sixth) when the storm's central pressure dropped to 902 mbar on August 28.
Hurricane Rita became the third most intense Atlantic hurricane (currently fourth) and the most intense hurricane on record in the Gulf of Mexico after reaching a pressure reading of 895 mbar on September 21.
Hurricane Wilma became the most intense Atlantic hurricane in recorded history (but note numerous have been more intense) at just before 5:00 am EDT on October 18, when the central pressure was measured at 884 mbar. At 8:00 am EDT, Wilma continued to intensify, reaching 882 mbar. Wilma also holds the record of being the only Category 4 storm in the Atlantic Basin to record a minimum central pressure below 900 mbar with a central pressure of 894 mbar and winds of 155 mph on October 20. Katrina, Rita and Wilma are the three most intense storms ever in a single Atlantic hurricane season.
2005 was the first time two storms recorded pressures below 900 millibars in a single season (Rita, 895; and Wilma, 882).
Hurricane Wilma also underwent the most rapid deepening for a 24-hour period ever measured. At noon on October 18, Wilma had a central pressure of 980 mbar (28.93 inches). At noon on October 19, Wilma had a central pressure of 882 mbar (26.04 inches), a pressure fall of 98 mbar (2.89 inches), breaking the previous record of 92 mbar (2.71 inches) set by Super Typhoon Forrest in the Western Pacific in 1983. Some sources, however, say that Forrest's pressure was lower than originally measured (876 mbar instead of 883 mbar). This fact would imply that Forrest retains the record with a pressure fall of 100 mbar in 24 hours, and thus this uncertainty is noted here.
In addition, Hurricane Dennis and Hurricane Emily, both in July, reached 930 mbar and 929 mbar respectively, becoming the two strongest storms on record in July.
Katrina was also the third most intense hurricane on record to make landfall in the United States in terms of pressure (920 mbar), behind the Labor Day Hurricane of 1935 and Hurricane Camille in 1969.
When Emily reached Category 5 intensity on July 16, it became the earliest Category 5 hurricane ever, shattering the record set by Hurricane Allen in the 1980 season. When Katrina reached Category 5 intensity on August 28, it became only the third time in recorded history (and the first time since the 1961 season) that there had been two Category 5 hurricanes in a single season. When Rita reached Category 5 intensity on September 21, 25 days after Katrina, the 2005 season became the first that had three Category 5 storms. When Wilma became a Category 5 storm on October 19, the 2005 season doubled the record set by the 1960 and 1961 seasons, becoming the first that had four Category 5 storms.

Rapid formation

Almost every storm in 2005 has set a record for early formation. The table shows the dates on which each storm formed, and the old record for earliest-forming storm of that number.

'Early formation of storms in 2005'
From the NHC "best track" data^[1]

Storm #	Formation Day	Name	Previous Record	Difference
1	June 9	Arlene	January 19, 1978	+141 days
2	June 28	Bret	May 17, 1887	+42 days
3	July 5	Cindy	June 11, 1887	+24 days
4	July 5	Dennis	Cindy - July 7, 1959	'-2 days'
5	July 11	Emily	Danny - July 16, 1997	'-5 days'
6	July 21	Franklin	August 4, 1936	'-14 days'
7	July 24	Gert	August 7, 1936	'-14 days'
8	August 3	Harvey	August 15, 1936	'-12 days'
9	August 7	Irene	August 20, 1936	'-13 days'
10	August 22	Jose	Jerry - August 23, 1995	'-1 day'
11	August 24	Katrina	August 28 1933/1936/ Karen - 1995	'-4 days'
12	August 31	Lee	Luis - August 29, 1995	+2 days
13	September 2	Maria	September 8, 1936	'-6 days'
14	September 5	Nate	September 10, 1936	'-5 days'
15	September 7	Ophelia	September 16, 1933	'-9 days'
16	September 17	Philippe	September 27, 1933	'-10 days'
17	September 18	Rita	September 28, 1933	'-10 days'
18	October 2	Stan	October 1, 1933	+1 day
19	October 4	Unnamed	October 25, 1933	'-21 days'
20	October 5	Tammy	October 26, 1933	'-21 days'
21	October 8	Vince	November 15, 1933	'-38 days'
22	October 17	Wilma	none	'N/A'
23	October 22	Alpha	none	'N/A'
24	October 27	Beta	none	'N/A'
25	November 18	Gamma	none	'N/A'
26	November 23	Delta	none	'N/A'
27	November 29	Epsilon	none	'N/A'
28	December 29	Zeta	none	'N/A'

Individual storms

The table below describes the characteristics of the individual storms. Included are data on the storms overall and on the landfalls of each. The colors are associated with the Saffir-Simpson scale of hurricane intensities, and are summarized in the table on the right side of this paragraph. (To see a brief description of how an intensity is defined, just place your cursor on the appropriate element of the right-hand table.)
It should be noted that even a non-landfalling storm can cause deaths and damage. Tropical cyclones are not point events. Storm related wind, rain and rough surf can be present hundreds of miles away from the center (although the greatest likelihood of storm-related damage and deaths occurs for landfalling storms and at landfall). Also land effects from storms after becoming extratropical or while a wave or low are not included in the landfall section, although they are included in the estimates for damage and deaths.

'Summary of the 2005 Atlantic hurricane season'

'Storm name'	'Active'	'Max wind'		'Min Press. (mbar/hPa)'	'Landfall(s)'				'Damages (millions 2005 USD)'	'Deaths'
					'Location'	'Date'	'Wind'
		'mph'	'km/h'				'mph'	'km/h'		'Direct'	'Indirect'
'Arlene'	8 June – 13 June	70	110	989	Cabo Corrientes, Cuba	10 June	50	85	11.8	1	0
					Pensacola, FL, US	11 June	60	90
'Bret'	28 June – 30 June	40	65	1002	Tuxpan, Mexico	29 June	40	60	9	2	0
'Cindy'	3 July – 7 July	75	120	991	south of Cozumel, Mexico	4 July	35	55	320	1	2
					Grand Isle, LA, US	5 July	75	120
					Ansley, MS, US	6 July	50	85
'Dennis'	4 July – 13 July	150	240	930	Grenada	4 July	35	55	4,000 – 6,000	42	47
					Cabo Cruz, Cuba	7 July	140	220
					near Cienfuegos, Cuba	8 July	140	220
					Navarre Beach, FL, US	10 July	120	195
'Emily'	10 July – 21 July	160	260	929	Grenada	14 July	85	140	550	6	9
					Tulum, Mexico	18 July	135	210
					San Fernando, Mexico	20 July	125	200
'Franklin'	21 July – 29 July	70	110	997	''None''				0	0	0
'Gert'	23 July – 25 July	45	75	1005	Cabo Rojo, Mexico	24 July	45	75	6	1	0
'Harvey'	2 August – 8 August	65	100	994	''None''				0	0	0
'Irene'	4 August – 18 August	105	165	970	''None''				0	0	0
'Ten'	13 August – 14 August	35	55	1008	''None''				0	0	0
'Jose'	22 August – 23 August	60	90	998	north of Veracruz, Mexico	22 August	60	90	45	6	2
'Katrina'	23 August – 31 August	175	275	902	north of Aventura, FL, US	25 August	80	130	≥81,200	≥1,8361
					Buras-Triumph, LA, US	29 August	125	200
					LA–MS border, US	29 August	120	195
'Lee'	28 August – 1 September	40	65	1006	''None''				0	0	0
'Maria'	1 September – 10 September	115	185	962	''None''				3.1	3	0
'Nate'	5 September – 10 September	90	145	979	''None''				0	1	0
'Ophelia'	6 September – 23 September	85	140	976	Grand Bahama, Bahamas	6 September	30	45	70	1	2
'Philippe'	17 September – 24 September	80	130	985	''None''				0	0	0
'Rita'	18 September – 26 September	180	285	895	LA–TX border, US	24 September	115	185	10,000	7	113
'Nineteen'	30 September – 2 October	35	55	1009	''None''				0	0	0
'Stan'	1 October – 5 October	80	130	977	south of Tulum, Mexico	2 October	40	65	1,000 – 2,000	80	1,540 – 2,000
					near Veracruz, Mexico	4 October	80	130
'Unnamed'	4 October – 5 October	50	85	997	''None''				0	0	0
'Tammy'	5 October – 6 October	50	85	1001	Mayport, FL, US	5 October	50	85	30	0	10
'Twenty-two'	8 October – 10 October	35	55	1009	''None''				0	0	0
'Vince'	8 October – 11 October	75	120	988	Huelva, Spain	11 October	30	45	0	0	0
'Wilma'	15 October – 25 October	185	295	882	Cozumel, Mexico	21 October	150	240	28,900	23	40
					Playa del Carmen, Mexico	22 October	140	220
					Cape Romano, FL, US	24 October	120	195
'Alpha'	22 October – 24 October	50	85	998	Barahona, Dominican Republic	23 October	50	85	5	26	17
'Beta'	26 October – 31 October	115	185	962	Atlántico Sur Province, Nicaragua	30 October	110	175	''Unknown''	0	0
'Gamma'	13 November – 21 November	50	85	1002	''None''				≥18	37	4
'Delta'	23 November – 28 November	70	110	980	''None''				≥364	7	0
'Epsilon'	29 November – 8 December	85	140	979	''None''				0	0	0
'Zeta'	29 December – 6 January 2006	65	100	994	''None''				0	0	0

¹Because of the devastating nature of Hurricane Katrina, assessment of the death toll is ongoing. Therefore, a distinction is not being drawn between direct and indirect deaths. It is estimated that approximately two-thirds of deaths caused by Katrina were indirect, resulting from poor conditions in New Orleans after the disaster.

Accumulated Cyclone Energy (ACE)

ACE (104 kt2) – Storm:
1	38.9	Wilma	15	5.41	Delta
2	32.9	Emily	16	5.39	Harvey
3	25.1	Rita	17	2.56	Arlene
4	20.0	Katrina	18	2.36	Stan
5	18.8	Dennis	19	1.66	Vince
6	15.7	Ophelia	20	1.52	Cindy
7	14.3	Maria	21	1.33	Gamma
8	13.4	Epsilon	22	0.810	Tammy
9	13.1	Irene	23	0.650	Alpha
10	7.17	Nate	24	0.528	Gert
11	6.72	Franklin	25	0.448	Jose
12	6.47	Beta	26	0.368	Bret
13	6.27	Zeta	27	0.245	Lee
14	5.95	Philippe	28	0.000	Unnamed
Total=248.059 (248)

The table to the right shows the tropical storms of the 2005 season ranked from highest to lowest Accumulated Cyclone Energy (ACE), given to three significant figures. The total for the season was 248 x 10⁴ kt² which is the highest seasonal ACE value recorded. It is slightly higher than that for 1950 season which had an ACE of 243 x 10⁴ kt². (It should be noted that the final storm of the season, Zeta, lasted into 2006. In calculating the seasonal ACE, the whole ACE of Zeta, including the contribution made in 2006, was used.)
ACE measures a combination of both the strength and duration of a tropical cyclone, so longer-lasting storms may accumulate more ACE than stronger storms with shorter durations. This discrepancy is most obvious in the comparatively high ACE value of Hurricane Emily to Hurricanes Katrina and Rita: Emily was not as strong as either storm, but formed out in the Atlantic and made a long track across the Caribbean Sea before making landfall. Katrina and Rita, however, both developed in the Bahamas, close to the U.S. mainland, and lasted for much shorter periods of time. In addition, Ophelia and Epsilon are high for their intensity because they maintained themselves for a long period of time and were slow to build and dissipate, as neither was ever more intense than a category 1 storm.
The average ACE per storm in 2005 was actually close to the seasonal average. In comparison with previous seasons with high seasonal ACE values, relatively few strong, long-lasting storms, such as Cape Verde-type hurricanes, formed. Thus, although the number of named storms in 2005 was about 40% greater than that in any season since 1950, the seasonal ACE was only marginally greater than the previous record, set in 1950 itself, when the average ACE per storm was approximately double that of 2005.
Source: Best Track data from the Tropical Cyclone Reports. ^[2]

Other records

Hurricane Vince was the farthest northeast that a tropical storm has ever formed in the Atlantic basin since records have been kept. It was also the first tropical cyclone on record to make landfall in mainland Europe without becoming extratropical.
Five storm names were retired - Dennis, Katrina, Rita, Stan, and Wilma. This breaks the record of four, previously held by the 1955, 1995, and 2004 Atlantic hurricane seasons.
The name Emily was not retired at the end of the season, making Hurricane Emily only the fourth ever category 5 hurricane since 1953 not to have its name retired. The others were Hurricane Edith (1971), Hurricane Ethel (1960), and Hurricane Cleo (1958), although the name Cleo was retired in 1964 due to another storm.

Notes

1. NHC/TPC Archive of Past Hurricane Seasons, Best Track data at bottom of page
2. List of Tropical Cyclone Reports for the 2005 AHS

References

★ NHC/TPC monthly Atlantic storm summaries for 2005

★ NHC/TPC storm advisory archives

★ NHC/TPC Tropical Cyclone Reports for 2005

★ Unisys 2005 Atlantic hurricane season data

★ Dr. Gray's forecast verification for 2005 (including storm descriptions through Beta)

★ Cory Pesaturo’s 2005 Atlantic Hurricane Season Records