Top ten global weather events of 2011

A remarkable blitz of extreme weather events during 2011 caused a total of 32 weather disasters costing at least $1 billion worldwide. Five nations experienced their most expensive weather-related natural disasters on record during 2011--Thailand, Australia, Colombia, Sri Lanka, and Cambodia. According to insurance broker AON Benfield's November Catastrophe Report, the U.S. was hit by no less than seventeen punishing multi-billion dollar extreme weather disasters in 2011; NOAA's National Climatic Data Center official total is lower--twelve--but is likely to grow in number as additional damage statistics are tallied. Brazil experienced its deadliest weather-related natural disaster--a flash flood that killed 902 people in January, and the Philippines had its second deadliest flood ever, when Tropical Storm Washi killed over 1200 people in December.





It was difficult to pick a top ten list of top weather events of 2011 from this bewildering list of candidates, and I cheated a bit by giving a tie for tenth place, so that eleven events would make the list. My list of top weather events were chosen based on their impact to society and meteorological significance. Damage estimates and death tolls for the 2011 disasters were mostly taken from AON Benfield's November Catastrophe Report, and records for damages and death tolls from disasters in previous years was taken from the Centre for Research on the Epidemiology of Disasters (CRED.) Here, then, is this year's top ten list. I've included links to some of my blogs posts made at the time of the disaster.

1) East Africa drought and famine: over 30,000 dead
The deadliest weather disaster of 2011 was a quiet one that got few headlines--the East African drought in Somalia, Kenya, and Ethiopia. On July 20, the United Nations officially declared famine in two regions of southern Somalia, the first time a famine has been declared by the UN in nearly thirty years. Almost 30,000 children under the age of five were believed to have died of malnutrition in Somalia this summer, and the total death toll of this great drought is doubtless much higher. East Africa has two rainy seasons--a main "long rains" of March - June, and the "short rains" of October - November. The "short rains" failed in the fall of 2010, and when the main "long rains" in spring 2011 also failed, it brought one of the worst droughts in recorded history. The 2010 - 2011 drought was rated along with the droughts of 1983 - 1984 and 1999 - 2000 as one of the three most significant droughts of the past 60 years. It was the driest 12-month period on record at some locations in East Africa. Damage assessments from the drought are not yet available, but it would not be a surprise if the drought of 2011 was the costliest weather-related natural disaster on record for Somalia, Ethiopia, and Kenya.

December 20 post: Deadliest weather disaster of 2011: the East African drought


Figure 1. Children fetch water at a tap installed by the International Rescue Committee (IRC) in the village of Darssalam in central Somalia. Image credit: IRC.

2) Thailand flooding: most expensive natural disaster in Thai history
Heavy monsoon and tropical cyclone rains from July through October, enhanced by La Niña conditions, led to unprecedented flooding that killed 657 people and caused Thailand's most expensive natural disaster in history. Damages are now estimated at $45 billion by re-insurance company AON Benfield. This is 18% of the country's GDP. Hurricane Katrina cost the U.S. about 0.7% of its GDP, so the Thailand floods can be thought of as a disaster 25 times worse than Katrina for that country. Thailand's previous most expensive natural disaster was the $1.3 billion price tag of the November 27, 1993 flood, according to the Centre for Research on the Epidemiology of Disasters (CRED). The floodwaters this year have hit 83% of Thailand's provinces, affected 9.8 million people, and damaged four million structures and approximately 25% of the nation's rice crop. Thailand is the world's largest exporter of rice, accounting for 30% of the global total, and the flood has helped trigger an increase in world rice prices in late 2011.

November 14 post: Thailand's flood gradually subsiding; climate change increasing Thai flood risk


Figure 2. An SH-60F Sea Hawk helicopter assigned to Helicopter Anti-Submarine Squadron (HS) 14, flies around the Bangkok area with members of the humanitarian assessment survey team and the Royal Thai Armed Forces to assess the damage caused by the 2011 floods. Image credit: Petty Officer 1st Class Jennifer Villalovos

3) Queensland, Australia flooding: most expensive natural disaster in Australian history
Heavy rains from December 2010 through January 2011, enhanced by La Niña conditions and record-warm ocean temperatures, led to unprecedented rains and flooding that killed 35 people and did $30 billion in damage. This was 3.2% of Australia's GDP, and five times more costly than the nation's previous most expensive natural disaster in history, the 1981 drought ($6 billion.) Rainfall in Queensland and all of eastern Australia in December 2010 was the greatest on record, and the year 2010 was the rainiest year on record for Queensland.

January 21 post: 2011: Year of the Flood


Figure 3. Still frame from a remarkable 6-minute YouTube video showing the sad fate of a row of parked cars when a flash flood in Toowoomba, Queensland sweeps away dozens of the cars. A note to the wise: Two minutes into the video, we see a man enter the flash flood to save his car. He is successful, but his actions were extremely risky--most flash flood deaths occur when cars with people inside get swept away.

4) Columbia floods: most expensive natural disaster in Colombia's history
Heavy rains in Colombia reached their peak in late April, triggering floods that killed 116 and did $5.85 billion in damage (2% of their GDP), making it the most damaging natural disaster in Colombia's history. Colombian President Juan Manuel Santos warned: “There are going to be a lot of needy people, there has never been a tragedy of this scale in our history.” Colombia's previous most expensive weather disaster occurred just last year, when the heaviest rains in 42 years of record keeping occurred. Floods and landslides killed 528, did $1 billion in damage, and left 2.2 million homeless in 2010. Colombia's most expensive natural disaster prior to 2011 was the $1.9 billion in damage from the January 25, 1999 earthquake, according to CRED.

5) Tropical Storm Washi: second deadliest weather disaster in Philippine history
Tropical Storm Washi hit the southern Philippine island of Mindanao as a tropical storm with 45 - 55 mph winds, crossing the island in about eighteen hours on December 16. Washi was unusually wet, as the storm was able to tap a large stream of tropical moisture extending far to the east, and drew moisture from an area where sea surface temperatures were nearly 1°C above average--one of the top five warmest values on record. Washi's rains fell on regions where the natural forest had been illegally logged or converted to pineapple plantations, and the heavy rains were able to run off quickly on the relatively barren soils and create devastating flash floods. Since the storm hit in the middle of the night, and affected an unprepared population that had no flood warning system in place, the death toll was tragically high. At least 1249 people perished, and 79 people are still listed as missing. The only deadlier storm ever to hit the Philippines was Tropical Storm Thelma on November 5, 1991, which killed 5956 people.

December 19 post: Tropical Storm Washi kills 632 in the Philippines


Figure 5. MODIS true-color satellite image of Tropical Storm Washi at 01:45 UTC December 16, 2011, as it bore down on the Philippines. At the time, Washi had top sustatined winds of 50 mph. Image credit: NASA.

6) Brazil flash flood kills 902: deadliest natural disaster in Brazil's history
Brazil suffered its deadliest natural disaster in history on January 11, when torrential rains inundated a heavily populated, steep-sloped area about 40 miles north of Rio de Janeiro. Flash floods and mudslides from the heavy rains have claimed 902 lives, including at least 357 in Nova Friburgo and 323 in Teresópolis. Rainfall amounts of approximately 300 mm (12 inches) fell in just a few hours in the hardest-hit regions. Damage estimates are $1.2 billion, making it the most damaging storm in Brazil's history, and third most damaging natural disaster, behind the $2.3 billion and $1.7 billion price tags of the 1978 and 2004 droughts. The previous deadliest flood in Brazilian history was a January 23, 1967 flood that killed 785 people.

January 14 post: At least 611 dead in Brazilian floods: Brazil's deadliest natural disaster in history


Figure 6. Flooded stream in Teresópolis. Image credit: Wikipedia.

7) April 25 - 28 Super" tornado outbreak kills 321 in the U.S.
On April 25 - 28, 2011, a massive tornado outbreak clobbered the Midwest and Southeast U.S. with 343 tornadoes. Now called the April 2011 Super tornado outbreak, it was the largest and most damaging tornado outbreak in U.S. history. The tornadoes caused 321 deaths, with 240 of those occurring in Alabama. The deadliest tornado of the outbreak, an EF-5, hit northern Alabama, killing 78 people. Several major metropolitan areas were directly impacted by strong tornadoes including Tuscaloosa, Birmingham, and Huntsville in Alabama and Chattanooga, Tennessee, causing the estimated damage costs to soar. The outbreak caused more than $7.3 billion insured losses and total losses greater than $10.2 billion.

April 29 post: Over 300 dead in historic tornado outbreak; one violent EF-5 tornado confirmed


Figure 7. The Piggly Wiggly supermarket and Family Dollar store after the EF-5 Hackleburg, Alabama tornado on April 27. Image credit: NWS Birmingham, Alabama.

8) Southern U.S./Northern Mexico drought: $10 billion in damage, and rising
Drought and excessive heat created major impacts across Texas, Oklahoma, New Mexico, Arizona, southern Kansas, western Louisiana, and northern Mexico. Texas endured its driest 1-year period on record, and rainfall in much of northern Mexico was the lowest since record keeping began in 1941. Texas had the hottest summer ever recorded by a U.S. state, and Oklahoma had the hottest month (July) any U.S. state has ever recorded. The total direct losses to crops, livestock and timber are estimated at $10 billion, but are expected to continue to rise as the drought continues into 2012. Record fires across the region caused an additional $1 billion in damage.

August 17 post: Texas heat wave smashes more records


Figure 8. Business was slow at the Lake Conroe, Texas jet ski rental in 2011, thanks to the great Texas drought of 2011. Image credit: wunderphotographer BEENE.

9) Pakistan floods: 2nd most expensive weather disaster in Pakistani history
Heavy rains during the July through September monsoon season triggered devastating flooding that killed 456 and did $2 billion in damage (1.1% of GDP) in Pakistan. It was the second most expensive weather-related disaster in Pakistan's history, behind the $9.5 billion price tag of the 2010 floods (5.5% of GDP.)

10 (tie) Hurricane Irene: most damaging tropical cyclone of 2011
The most damaging tropical cyclone on the globe during 2011 was Hurricane Irene, which plowed through the Bahama Islands as a Category 3 hurricane with 120 mph winds before striking North Carolina as a Category 1 hurricane with 85 mph winds on August 27. Most of Irene's damage occurred after it made landfall on Long Island, New York as a tropical storm with 65 mph winds, when torrential rainfall triggered extreme flooding in the Northeast U.S. More than 7 million homes and businesses lost power during the storm. Irene caused at least 45 deaths in the U.S., and ten in the Caribbean and Bahamas. Damage is estimated at $7.3 billion.

December 3 post: Hurricane Irene: New York City dodges a potential storm surge mega-disaster


Figure 9. GOES-East visible satellite image of Irene taken at 7:45 am EDT on Sunday, August 28, 2011. At the time, Irene was a tropical storm with 65 mph winds, making landfall on Long Island, New York. Image credit: NOAA Environmental Visualization laboratory.

10 (tie) May 22 - 27 Joplin, Missouri tornado outbreak
A violent EF-5 tornado carved a ½ – ¾ mile-wide path of devastation through Joplin, Missouri on May 22, killing 158, and causing $3 billion in damage. Huge sections of the town virtually obliterated, and damage from the tornado was so severe that pavement was ripped from the ground. It was the largest death toll from a U.S. tornado since 1947, seventh deadliest tornado in U.S. history, and the most expensive tornado in world history. The six-day outbreak spawned 180 tornadoes in the central and southern states, killed 177, and did $9.1 billion in damage.

May 23 post: Deadliest U.S. tornado since 1953 rips through Joplin, Missouri, killing 89


Video 1. Video of the Joplin, Missouri tornado of May 22, 2011, entering the southwest side of town. Filmed by TornadoVideos.net Basehunters team Colt Forney, Isaac Pato, Kevin Rolfs, and Scott Peake. The most remarkable audio I've ever heard of people surviving a direct hit by a violent tornado was posted to Youtube by someone who took shelter in the walk-in storage refrigerator at a gas station during the Joplin tornado. There isn't much video.

Honorable mentions:
1) Sri Lanka: Heaviest rains in nearly a century of record keeping triggered a 1-in-100 year flood in January that killed 43 and did $500 million in damage--the costliest weather-related disaster in Sri Lanka's history. Renewed rains February 1 - 10 caused flooding that killed 18 and cost an additional $450 million--the second most costly natural disaster in Sri Lanka's history.

2) Heavy rains in September and October in Cambodia triggered flooding that killed 250 and did $521 million in damage--by far the most expensive natural disaster in Cambodian history. The previous most expensive disaster was the $160 million cost of floods in July 2000.

3) El Salvador: Heavy rains from Tropical Depression 12-E in October triggered flooding that killed 140 in Central America and caused $900 million in damage to El Salvador (4.2% of GDP). This is the 2nd most expensive weather-related disaster in El Salvador's history, behind the $939 million price tag of their Nov. 7, 2009 flood.

4) China: June floods in China killed 239, doing $6.65 billion in damage, the 10th most damaging weather-related disaster in Chinese history.

5) China: September floods killed 101 and did $4.25 billion in damage.

6) U.S.: Greatest flood on the Lower Mississippi River on record caused $4 billion in damage.

7) China: A drought in Northern China during January through April cost $2.7 billion.

8) Denmark: Severe flooding on July 2 - 3 caused $1 billion in damage, the 3rd most expensive weather-related disaster in Danish history.

Other posts looking back at the remarkable weather events of 2011
2011: Year of the Tornado
Deadliest weather disaster of 2011:; the East African drought
Tropical Storm Lee's flood in Binghamton: was global warming the final straw?
Wettest year on record in Philadelphia; 2011 sets record for wet/dry extremes in U.S.
Hurricane Irene: New York City dodges a potential storm surge mega-disaster

Donations sought for the East Africa famine
Weather Underground has partnered with the International Rescue Committee (IRC) to help the Horn of Africa region during the ongoing famine. With the help of the Weather Underground community, we hope to raise $10,000 that will go toward helping the refugees survive the crisis. Weather Underground will match the community's donation dollar-for-dollar up to $10,000 for a total donation of $20,000. Please visit the East Africa famine donation page to help out. Ninety cents of every dollar donated goes directly to the people in need.

This will be my last post until Tuesday, as its time to gather with family and friends and celebrate the arrival of the new year. Happy New Year, everyone!

Jeff Masters