2011 natural disasters

The 2011 Nabro eruption was an eruption of the Nabro stratovolcano in the Southern Red Sea Region of Eritrea, which began on 12 June 2011 after a series of earthquakes. The eruption killed seven and possibly a further 31 people and is estimated to be the highest altitude injection of sulfur dioxide (SO2) ever observed by satellite. The Mount Pinatubo eruption 20 years earlier emitted ten times more SO2. The ash cloud from the eruption reached altitudes which disrupted airline traffic in the region. Until the eruption began, the volcano had no records of historical eruptions.

The 2011–2012 Puyehue-Cordón Caulle eruption was a volcanic eruption that began in the Puyehue-Cordón Caulle volcanic complex in Chile on 4 June 2011. The eruption, which occurred from the Cordón Caulle fissure after 51 years of the volcano being inactive, is one of the largest volcanic eruptions of the 21st century thus far. At least 3,500 people were evacuated from nearby areas, while the ash cloud was blown across cities all around the Southern hemisphere, including Bariloche, Buenos Aires, Montevideo, Stanley, Porto Alegre, Cape Town, Hobart, Perth, Adelaide, Sydney, Melbourne, Wellington, Auckland and Port Moresby, forcing airlines to cancel hundreds of international and domestic flights and causing travel chaos.

Tropical Storm Rolf, also known as Tropical Storm 01M, was an unusual and damaging Mediterranean tropical storm that brought flooding to Italy, France, Spain, and Switzerland in November 2011. Rolf originated from an extratropical system near western France on 4 November. Despite the generally unfavorable conditions in the Mediterranean Sea, Rolf transitioned into a subtropical depression on 7 November, before becoming a tropical storm later that day. On 8 November, Rolf reached its peak intensity, with 1-minute sustained winds peaking at 85 km/h (53 mph) and a minimum central pressure of 991 mb (29.3 inHg). During the next day, the storm made landfall on the island of Île du Levant, in France, and soon afterward, near Hyères in southeastern France. Following its second landfall, Rolf quickly weakened and dissipated on 10 November. Rolf was the first tropical cyclone ever to be officially monitored by the NOAA in the Mediterranean Sea.

Hurricane Bawbag, also known as Cyclone Friedhelm was an intense extratropical cyclone which brought hurricane-force winds to Scotland at the beginning of December 2011. The storm also brought prolonged gales and rough seas to the rest of the British Isles, as well as parts of Scandinavia. On 8 December, winds reached up to 165 mph (266 km/h) at elevated areas, with sustained wind speeds of up to 80 mph (130 km/h) reported across populous areas. The winds uprooted trees and resulted in the closure of many roads, bridges, schools and businesses. Overall, the storm was the worst to affect Scotland in 10 years, though a stronger storm occurred less than a month afterwards, on 3 January 2012. Although the follow-up storm was more intense, the winter of 2011–12 is usually remembered for Bawbag among Scots.

The 2011 Tuvalu drought was a period of severe drought afflicting Tuvalu, a South Pacific island country of approximately 10,500 people, in the latter half of 2011. A state of emergency was declared on September 28, 2011; with rationing of available fresh-water. The La Niña event that caused the drought ended in April–May 2012. By August 2012 the El Niño-Southern Oscillation (ENSO) Conditions indicated that the tropical Pacific Ocean was on the brink of an El Niño event.

The winter of 2010–11 was a weather event that brought heavy snowfalls, record low temperatures, travel chaos and school disruption to the islands of Great Britain and Ireland. It included the United Kingdom's coldest December since Met Office records began, with a mean temperature of −1 °C (30 °F), breaking the previous record of 0.1 °C (32.2 °F) in December 1981. It was also the second coldest December in the narrower Central England Temperature (CET) record series which began in 1659, falling 0.1 °C short of the all-time record set in 1890. Although data has never officially been compiled, December 2010 is thought to be colder than December 1890 over the United Kingdom as a whole, as Scotland was up to 2 °C warmer than England. Hence, it is thought to be the coldest December across Great Britain since before 1659.

The winter of 2010–2011 in Europe began with an unusually cold November caused by a cold weather cycle that started in southern Scandinavia and subsequently moved south and west over both Belgium and the Netherlands on 25 November and into the west of Scotland and north east England on 26 November. This was due to a low pressure zone in the Baltics, with a high pressure over Greenland on 24 November, and ended on 3 May 2011 in Poland.

The 2011 eruption of Grímsvötn was an eruption in Grímsvötn, Iceland's most active volcano, which caused disruption to air travel in Northwestern Europe from 22–25 May 2011. The last eruption of Grímsvötn was in 2004, with the previous most powerful eruptions in 1783, 1873 and 1902. The Grímsvötn eruption was the largest eruption in Iceland for 50 years.