Tropical cyclones in 2011

During 2011, tropical cyclones formed within seven different tropical cyclone basins, located within various parts of the Atlantic, Pacific and Indian Oceans. During the year, a total of 131 tropical cyclones had formed this year to date. 71 tropical cyclones had been named by either a Regional Specialized Meteorological Center (RSMC) or a Tropical Cyclone Warning Center (TCWC). Thirty-nine of these named systems eventually intensified into hurricane-equivalent tropical cyclones. The most active basin in the year was the Western Pacific, which documented 21 named storms. North Atlantic basin documented 19 named storms, continuing the consecutive third-most active season trends from the previous year, due to the 2010–12 La Niña event. Conversely, the Eastern Pacific basin featured slightly more activity than the previous season, with 11 named storms. The least active basin in the year was the North Indian Ocean basin which documented only 2 named storms, the lowest since the 1993 season. Activity across the Southern Hemisphere were almost evenly spread, with the South-West Indian Ocean basin recording 10 tropical cyclones, the Australian region recording 17 tropical cyclones, and the South Pacific basin also recording 10 tropical cyclones, respectively. Twenty-one Category 3 tropical cyclones formed in the year, including three Category 5 tropical cyclones. The accumulated cyclone energy (ACE) index for the 2011 (seven basins combined), as calculated by Colorado State University was 573.8 units.

Tropical cyclones in 2011
Year summary map
Year boundaries
First system	03
Formed	January 2, 2011
Last system	Benilde
Dissipated	January 4, 2012
Strongest system
Name	Songda
Lowest pressure	920 mbar (hPa); 27.17 inHg
Longest lasting system
Name	Philippe
Duration	14 days
Year statistics
Total systems	131
Named systems	71
Total fatalities	3,702 total
Total damage	$29.86 billion (2011 USD)
Related articles 2011 Atlantic hurricane season 2011 Pacific hurricane season 2011 Pacific typhoon season 2011 North Indian Ocean cyclone season 2010–11 South-West Indian Ocean cyclone season 2011–12 South-West Indian Ocean cyclone season 2010–11 Australian region cyclone season 2011–12 Australian region cyclone season 2010–11 South Pacific cyclone season 2011–12 South Pacific cyclone season
Other years 2009, 2010, 2011, 2012, 2013

Satellite photos of the 21 tropical cyclones worldwide that reached at least Category 3 on the Saffir–Simpson scale during 2011, from Wilma in January to Kenneth in November.
Among them, Songda (third-to-last image in the first row) was the most intense, with a minimum central pressure of 920 hPa.

The strongest tropical cyclone of the year was Typhoon Songda, with a minimum central pressure of 920 hPa (mbar). The costliest tropical cyclone of the year was Hurricane Irene, which caused $14.2 billion worth of damage. The deadliest tropical cyclone of the year was Severe Tropical Storm Washi, which killed 2,546 people.

Global atmospheric and hydrological conditions

See also: 2010–12 La Niña event

The strong La Niña from the previous year continued into 2011, whereby it peaked in January.^[1] Afterwards, it began weakening considerably, to the point where in May it was determined that a transition to neutral conditions took place.^[2] By the end of Summer, this neutral state continued to persist, although there were still remnants of the La Niña evident.^[3] Due to continued cooling of the Pacific, it was determined that the La Niña redeveloped, albeit in a weak state, which would then continue into the next year.^[4]

Summary

Systems

January

Cyclone Yasi

During January 2011, a total of 12 tropical cyclones, all of them, formed within the southern hemisphere. No tropical cyclone was observed in the northern hemisphere. Of the systems, 7 further intensified to become named. Out of the systems, Wilma was the most intense tropical cyclone, with a minimum barometric pressure of 935 mbar/hPa.

Tropical cyclones formed in January 2011

Storm name	Dates active	Max wind km/h (mph)	Pressure (hPa)	Areas affected	Damage (USD)	Deaths	Refs
03	January 2–3	55 (35)	996	Madagascar	None	None	[5]
Vania	January 5–15	100 (65)	973	Vanuatu, Fiji, New Caledonia, New Zealand	unknown	unknown	[citation needed]
04F	January 5–7	185 (115)	1002	New Caledonia	$25 million	3 direct, 1 indirect
Vince	January 10—15	75 (45)	986	None	None	None
Zelia	January 12—17	185 (115)	943	New Caledonia, Norfolk Island, New Zealand	None	None
Wilma	January 19–29	185 (115)	935	Samoan Islands, Tonga, New Zealand	$22 million	3	[6]
07F	January 20–22	65 (40)	996	New Caledonia	None	None
Anthony	January 22–31	95 (60)	989	Queensland	Minor	None	[citation needed]
Bianca	January 23–30	175 (110)	949	Northern Territory, Western Australia	Unknown	2	[7]
Yasi	January 26–February 3	205 (125)	929	Tuvalu, Fiji, Solomon Islands, Vanuatu, Papua New Guinea, Australia	$3.6 billion	1	[citation needed]
04	January 30–31	45 (30)	998	Réunion	None	None
13U	January 31	Not Specified	Not Specified	None	None	None

February

Cyclone Atu

10 systems formed and 5 named storms during February.

Tropical cyclones formed in February 2011

Storm name	Dates active	Max wind km/h (mph)	Pressure (hPa)	Areas affected	Damage (USD)	Deaths	Refs
BOB 01	February 2–3	45 (30)	1002	Sri Lanka	297 million	18	[8]
Zaka	February 5–7	95 (60)	985	None	None	None
15U	February 8–13	55 (35)	996	None	None	None
Bingiza	February 9–17	155 (100)	957	Comoros, Madagascar	Unknown	34	[citation needed]
Atu	February 13–24	165 (105)	940	Vanuatu	Unknown	None	[citation needed]
Dianne	February 14–22	140 (85)	960	Western Australia	Minimal	None	[citation needed]
Carlos	February 14–27	120 (75)	969	Northern Territory, Western Australia	$12.3 million	None	[citation needed]
06	February 15–18	45 (30)	1000	None	None	None
18U	February 23–28	55 (35)	992	None	None	None
19U	February 26–March 1	Not Specified	1000	Northern Territory	None	None

March

Cyclone Bune

March was a relatively inactive month in which 11 systems formed, and only 3 received names.

Tropical cyclones formed in March 2011

Storm name	Dates active	Max wind km/h (mph)	Pressure (hPa)	Areas affected	Damage (USD)	Deaths	Refs
20U	March 5	Not Specified	Not Specified	None	None	None
21U	March 7–8	45 (30)	1004	None	None	None
12F	March 7–9	45 (30)	1002	Vanuatu	None	None
22U	March 10–15	Not Specified	Not Specified	None	None	None
Cherono	March 10–23	75 (45)	993	Rodrigues Island	None	None
Arani	March 14–16	85 (50)	989	Brazil	None	None
Bune	March 22 – 29	130 (80)	967	Fiji	None	None
25U	March 26–April 6	55 (35)	994	None	None	None
08	March 29–31	45 (30)	1004	None	None	None
26U	March 30–April 1	Not Specified	1006	None	None	None
27U	March 30–April 1	Not Specified	1006	None	None	None

April

Subtropical Depression 09

Cyclone Errol

Tropical cyclones formed in April 2011

Storm name	Dates active	Max wind km/h (mph)	Pressure (hPa)	Areas affected	Damage (USD)	Deaths	Refs
01W	April 1–4	55 (35)	1004	None	None	None
02W (Amang)	April 3–6	55 (35)	1000	Mariana Islands	None	None
14F	April 10–11	Not Specified	1005	Vanuatu	None	None
09	April 11–16	95 (60)	985	None	None	None
28U	April 14–15	Not Specified	Not Specified	None	None	None
Errol	April 14–20	100 (65)	986	Indonesia, Western Australia, Northern Territory	None	None
15F	April 15–17	55 (35)	999	None	None	None
16F	April 28–30	Not Specified	1002	None	None	None

May

Typhoon Songda

May was a mostly inactive month in which only 4 tropical cyclones formed, in which 2 received names.

Tropical cyclones formed in May 2011

Storm name	Dates active	Max wind km/h (mph)	Pressure (hPa)	Areas affected	Damage (USD)	Deaths	Refs
Aere (Bebeng)	May 5–12	75 (45)	992	Philippines, Japan	$34.4 million	48	[citation needed]
17F	May 10–11	55 (35)	1000	None	None	None
Songda (Chedeng)	May 19–29	195 (120)	920	Micronesia, Philippines, Japan	$287 million	17	[citation needed]
TD	May 31–June 1	Not specified	1004	None	None	None

June

Hurricane Adrian

Tropical cyclones formed in June 2011

Storm name	Dates active	Max wind km/h (mph)	Pressure (hPa)	Areas affected	Damage (USD)	Deaths	Refs
Adrian	June 7–12	220 (140)	944	Southwestern Mexico	None	None
Sarika (Dodong)	June 8–11	75 (45)	996	Philippines, China	$248 million	28	[citation needed]
ARB 01	June 11–12	45 (30)	996	India	None	None
TD	June 14–15	Not specified	1004	China	None	None
Haima (Egay)	June 16–25	75 (45)	985	Philippines, China, Vietnam, Laos, Thailand	$167 million	18	[citation needed]
BOB 02	June 16–23	65 (40)	978	India	None	6	[citation needed]
Beatriz	June 19–22	150 (90)	977	Southwestern and Western Mexico	None	4	[citation needed]
Meari (Falcon)	June 20–27	110 (70)	970	Philippines, China, Japan, Korea	$1.24 million	11	[citation needed]
Arlene	June 28–July 1	100 (65)	993	Central America, Mexico, Texas, Florida	$223.4 million	22	[citation needed]

July

Hurricane Dora

Tropical cyclones formed in July 2011

Storm name	Dates active	Max wind km/h (mph)	Pressure (hPa)	Areas affected	Damage (USD)	Deaths	Refs
Calvin	July 7–10	130 (80)	984	None	None	None
Goring	July 8–10	45 (30)	1000	Taiwan, China	None	None
Ma-on (Ineng)	July 11–24	175 (110)	935	Northern Mariana Islands, Japan	$50 million	5	[citation needed]
Tokage (Hanna)	July 13–15	65 (40)	1000	None	None	None
TD	July 16–17	Not specified	1000	China	None	None
Bret	July 17–22	110 (70)	995	Bahamas, Bermuda, East Coast of the United States	None	None
Dora	July 18–24	250 (155)	929	Southwestern Mexico, Western Mexico, Baja California Peninsula, Southwestern United States	Minimal	None	[citation needed]
Cindy	July 20–22	110 (70)	994	Bermuda	None	None
LAND 01	July 22–23	35 (25)	990	India	None	None
Nock-ten (Juaning)	July 24–31	95 (60)	985	Philippines, China, Vietnam, Laos, Thailand	$126 million	128	[citation needed]
Muifa (Kabayan)	July 25–August 9	175 (110)	930	Micronesia, Caroline Islands, Philippines, Japan, China, Korea, Russia	$480 million	22	[citation needed]
Don	July 27–30	85 (50)	997	Cuba, Yucatán Peninsula, Northeastern Mexico, Texas	None	None
Lando	July 31–August 2	Not specified	1002	Philippines	None	None
Eugene	July 31–August 6	220 (140)	942	None	None	None

August

Typhoon Nanmadol

Hurricane Katia

August was the most active month of 2011, with 18 systems forming in the month.

Tropical cyclones formed in August 2011

Storm name	Dates active	Max wind km/h (mph)	Pressure (hPa)	Areas affected	Damage (USD)	Deaths	Refs
Emily	August 2–7	85 (50)	1003	Antilles, Florida, Bahamas	$5 million	5	[citation needed]
Merbok	August 2–9	95 (60)	980	None	None	None
TD	August 2–4	55 (35)	1008	Japan	None	None
13W	August 8–14	55 (35)	1004	None	None	None
TD	August 8–10	55 (35)	1008	None	None	None
Franklin	August 12–13	75 (45)	1004	Bermuda	None	None
Gert	August 13–16	100 (65)	1000	Bermuda	None	None
Fernanda	August 15–19	110 (70)	992	None	None	None
Greg	August 16–21	140 (85)	979	None	None	None
Harvey	August 19–22	100 (65)	994	Lesser Antilles, Hispaniola, Central America, Mexico	Minimal	5	[citation needed]
TD	August 20–25	55 (35)	1004	None	None	None
Irene	August 21–28	195 (120)	942	Lesser Antilles, Greater Antilles, Turks and Caicos, Bahamas, East Coast of the United States, Vermont, Atlantic Canada	$14.2 billion	58	[citation needed]
Nanmadol (Mina)	August 21–31	185 (115)	925	Philippines, Taiwan, China	$1.49 billion	38	[citation needed]
Talas	August 23–September 5	95 (60)	970	Japan	$600 million	82	[citation needed]
Ten	August 25–26	55 (35)	1006	None	None	None
Jose	August 26–29	75 (45)	1006	Bermuda	None	None
Katia	August 29–September 10	220 (140)	942	Lesser Antilles, East Coast of the United States, Canada, United Kingdom	$157 million	4	[citation needed]
Eight-E	August 31–September 1	55 (35)	1002	Southwestern Mexico, Western Mexico	None	None

September

Typhoon Nalgae

Hurricane Hilary

September was a below-average month, with only 16 tropical cyclones forming in that month.

Tropical cyclones formed in September 2011

Storm name	Dates active	Max wind km/h (mph)	Pressure (hPa)	Areas affected	Damage (USD)	Deaths	Refs
Unnamed	September 1–3	75 (45)	1002	None	None	None
Lee	September 2–5	95 (60)	986	Gulf Coast of the United States, Eastern United States	$2.8 billion	18	[citation needed]
Noru	September 2–6	75 (45)	990	None	None	None
Kulap (Nonoy)	September 6–11	65 (40)	1000	Japan, Korea	None	None
Maria	September 6–16	130 (80)	983	Lesser Antilles, Bermuda, Newfoundland, Europe	$1.3 million	None	[citation needed]
Nate	September 7–11	120 (75)	994	Mexico	Minimal	5	[citation needed]
Roke (Onyok)	September 8–22	155 (100)	940	Japan, Russia, Alaska	$1.2 billion	13	[citation needed]
TD	September 13–15	Not specified	1002	Taiwan	None	None
Sonca	September 14–20	130 (80)	970	None	None	None
Ophelia	September 20–October 3	220 (140)	940	Leeward Islands, Bermuda, Newfoundland	Minimal	None	[citation needed]
Hilary	September 21–30	230 (145)	942	Southwestern Mexico	Minimal	None	[citation needed]
BOB 03	September 22–23	45 (30)	995	India	Unknown	42	[citation needed]
Nesat (Pedring)	September 23–30	150 (90)	950	Philippines, China, Vietnam	$2.12 billion	98	[citation needed]
Haitang	September 24–27	65 (40)	996	China, Vietnam, Laos	$20 million	25	[citation needed]
Philippe	September 24–October 8	150 (90)	976	Cape Verde	None	None
Nalgae (Quiel)	September 26–October 5	175 (110)	935	Philippines, China, Vietnam	$250 million	18	[citation needed]

October

Hurricane Jova

Tropical cyclones formed in October 2011

Storm name	Dates active	Max wind km/h (mph)	Pressure (hPa)	Areas affected	Damage (USD)	Deaths	Refs
Jova	October 6–13	205 (125)	955	Southwestern Mexico, Western Mexico	≥$204 million	9	[citation needed]
Irwin	October 6–16	155 (100)	976	Western Mexico	None	None
Banyan (Ramon)	October 9–14	65 (40)	1002	Palau, Philippines	$2.1 million	10	[citation needed]
TD	October 10–13	Not specified	1006	China, Vietnam	None	None
Twelve-E	October 12	35 (55)	1004	Southwestern Mexico, Central America	Unknown	30	[citation needed]
BOB 04	October 19–20	55 (35)	1002	Bangladesh, Myanmar	1.64 million	215	[citation needed]
Rina	October 23–28	185 (115)	966	Central America, Yucatán Peninsula, Cuba, Florida	$2.3 million	None	[citation needed]
Keila	October 29–November 4	65 (40)	996	Oman, Yemen	$80 million	14	[citation needed]

November

Hurricane Kenneth

November was inactive with only 7 tropical cyclones forming, as well as Rolf, a system that formed in the Mediterranean sea.

Tropical cyclones formed in November 2011

Storm name	Dates active	Max wind km/h (mph)	Pressure (hPa)	Areas affected	Damage (USD)	Deaths	Refs
ARB 03	November 6–10	55 (35)	1000	None	None	None
Rolf	November 6–9	85 (50)	991	Italy, France, Switzerland, Spain	>$1.25 billion	12	[citation needed]
24W	November 7–10	45 (30)	1004	Vietnam	None	None
Sean	November 8–11	100 (65)	982	Bermuda	Minimal	1	[citation needed]
01F	November 13–16	Not Specified	1004	Fiji	None	None
Kenneth	November 19–25	230 (145)	940	None	None	None
ARB 04	November 26–December 1	55 (35)	998	Lakshadweep, India, Sri Lanka, Maldives	Unknown	19	[citation needed]

December

Cyclone Benilde

Tropical cyclones formed in December 2011

Storm name	Dates active	Max wind km/h (mph)	Pressure (hPa)	Areas affected	Damage (USD)	Deaths	Refs
Alenga	December 3–11	140 (85)	972	None	None	None
25W	December 4–5	45 (30)	1006	Brunei, Malaysia	None	None
02	December 6–9	55 (35)	998	Mauritius	None	None
26W	December 10–14	55 (35)	1004	Philippines	None	4	[citation needed]
Washi (Sendong)	December 13–19	95 (60)	992	Philippines, Micronesia, Palau	$97.8 million	2,546	[citation needed]
Fina	December 18–23	65 (40)	994	Papua New Guinea, New Caledonia	None	None
03	December 19–23	55 (35)	1000	Madagascar	None	None
Benilde	December 21–January 4	150 (90)	968	None	None	None
Grant	December 21–January 2	100 (65)	978	Northern Territory	Minor	None	[citation needed]
TD	December 24	Not specified	1002	None	None	None
Thane	December 25–December 31	140 (85)	969	India, Sri Lanka	$235 million	46	[citation needed]
05U	December 26–28	Not Specified	Not Specified	None	None	None
02F	December 28–January 1	Not Specified	1002	Niue, Cook Islands	None	None
TD	December 31–January 1	Not specified	1008	Malaysia	None	None

Global effects

Season name	Areas affected	Systems formed	Named storms	Damage (USD)	Deaths
2011 Atlantic hurricane season 1	Central America, Mexico, Texas, Florida, Bahamas, Bermuda, East Coast of the United States, Cuba, Yucatán Peninsula, Northeastern Mexico, Antilles, Lesser Antilles, Hispaniola, US Virgin Islands, Puerto Rico, Lucayan Archipelago, Eastern United States, North Carolina, New Jersey, Canada, Gulf Coast of the United States, Newfoundland, Europe, Leeward Islands, Quintana Roo,	20	18	$17.39 billion	118
2011 Pacific hurricane season 1	Southwestern Mexico, Western Mexico, Baja California Peninsula, Southwestern United States, Central America	13	11	$203.67 million	43
2011 Pacific typhoon season 2 3	Mariana Islands, Philippines, Japan, Micronesia, China, Vietnam, Laos, Thailand, Korea, Taiwan, Caroline Islands, Palau, Malaysia	39	21	$7.68 billion	3,111
2011 North Indian Ocean cyclone season	Sri Lanka, India, Bangladesh, Myanmar, Oman, Yemen, Lakshadweep,	10	2	$603.64 million	367
2010–11 South-West Indian Ocean cyclone season 2	Comoros, Madagascar, Réunion	7	2	None	34
2011–12 South-West Indian Ocean cyclone season 3	Madagascar	3	2	None	None
2010–11 Australian region cyclone season 2	Northern Territory, Western Australia, Solomon Islands, Indonesia	19	7	$2.7 billion	3
2011–12 Australian region cyclone season	Papua New Guinea, Northern Territory	4	2	None	None
2010–11 South Pacific cyclone season 2	Fiji, Vanuatu, New Caledonia, New Zealand, Norfolk Island, Samoan Islands, Tonga	15	7	>$33 million	14
2011–12 South Pacific cyclone season 3	Fiji, Niue, Cook Islands	2	0	None	None
South Atlantic tropical cyclone	Brazil	1	1	None	None
Mediterranean tropical-like cyclone	Italy, France, Switzerland, Spain	1	1	> $1.25 billion	12
Worldwide	(See above)	134[a]	74	$29.86 billion	3,702

1. The sum of the number of systems and fatalities in each basin will not equal the number shown as the total. This is because when systems move between basins, it creates a discrepancy in the actual number of systems and fatalities.

See also

• Tropical cyclones portal

• Tropical cyclones by year
• List of earthquakes in 2011
• Tornadoes of 2011

Notes

¹The "strength" of a tropical cyclone is measured by the minimum barometric pressure, not wind speed. Most meteorological organizations rate the intensity of a storm by this figure, so the lower the minimum pressure of the storm, the more intense or "stronger" it is considered to be.
² Only systems that formed either on or after January 1, 2011 are counted in the seasonal totals.
³ Only systems that formed either before or on December 31, 2011 are counted in the seasonal totals.
⁴ The wind speeds for this tropical cyclone/basin are based on the IMD Scale which uses 3-minute sustained winds.
⁵ The wind speeds for this tropical cyclone/basin are based on the Saffir Simpson Scale which uses 1-minute sustained winds.
⁶The wind speeds for this tropical cyclone are based on Météo-France which uses wind gusts.