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May-June 2011

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Global Weather Highlights 2010: Flooding, Heatwaves, and Fires

Caption: Residents stare in awe at the Werribee River flood in Australia.

Caption: Residents stare in awe at the Werribee River flood in Australia.

Catastrophic monsoon flooding created a humanitarian disaster in Pakistan this summer, while an epic heat wave and drought in Russia triggered widespread fires, suffocating smog, and major crop losses. Bad weather in Asia and Canada reduced crop production and contributed to soaring commodity and food prices.

Cold, Snow, and Storm in Europe

The same negative North Atlantic Oscillation (NAO) pattern responsible for the severe wintery weather in the United States brought severe cold and snow to northern Europe, resulting in traffic delays and power outages. The United Kingdom experienced its coldest January since 1987 and widespread snow during the first half of the month. The minimum temperature of −22.3°C (−8°F) on January 8 at Altnaharra in the Scottish Highlands was the lowest temperature in the UK since 1995. Following heavy snow on January 5–6, snow depths ranged as high as 57 cm (22.5 in) in northeast England. The snow caused the closure of 12,000 schools.

Caption: Manchester, England, was buried under snow in early January 2010.

Caption: Manchester, England, was buried under snow in early January 2010.

Snow and cold extended into Scandinavia and Russia, and also gripped northeast Asia. Temperatures in Beijing dropped to −18°C (−2°F) during the first week of January.

One of Europe's most severe winter storms of the past 10 years made landfall on February 28 along France's Atlantic coast. Hurricane-force winds from Xinthia, as it was named, downed trees and power lines, while heavy rains and high waves caused deadly flooding. The storm was blamed for 63 deaths across Europe, with the bulk of the fatalities in France, where at least 51 died. Over 1 million households in France lost power, and heavy rains, storm surge, and mountainous waves flooded coastal villages. The low pressure center reached a minimum pressure of 967 mb (28.55 inches) on February 27 as it approached the French coast. Winds gusted to 166 km/h (103 mph) or more in parts of France, Portugal, and Spain. In Paris, the top of the Eiffel Tower experienced gusts to 155 km/h (96 mph). According to Swiss Re, insured losses from Xinthia totaled $2.8 billion, making this storm only somewhat less damaging than Klaus in January 2009.

The El Niño that emerged in the summer of 2009 persisted through the 2009–2010 winter. El Niño usually results in mild winter weather for the Canadian Pacific coast, and this was recognized as a potential problem for the 2010 Winter Olympics at Vancouver, which opened on February 12. Ironically, the Vancouver Organizing Committee promised that this Olympics would be the “greenest on record.” “Oh, were they right!” quipped Environment Canada (EC) in its summary of annual weather events. Vancouver experienced its mildest winter ever and was nearly snow-free, causing problems even before the opening of the games. Either mild and rainy weather or mild and sunny weather prevailed across the lower-elevation events, and even at the high-elevation Whistler site, heavy, wet snow and thick fog posed challenges for competitors. Nevertheless, thanks in part to the diligent efforts of hundreds of workers moving thousands of cubic meters of snow, the events took place, the spectators spectated, and visitors could admire the blossoming cherry trees in British Columbia.

This was not only a mild winter for the Canadian West Coast, but an extraordinarily warm year for the nation. Canada's mildest winter was followed by its warmest spring, its third warmest summer, and its second warmest fall. As a result, 2010 was Canada's warmest year in 63 years.

In the Canadian Prairies, a dry spring initially stoked farmers' concerns that drought would be a problem this year. Rains starting up in mid-April were welcomed, but then the rains kept on coming and would not let up for months. This was the wettest spring on record in the Prairies, and the rains persisted through summer. Several million hectares of wheat went unseeded, the largest abandoned acreage since 1971. Spring made it too wet to seed, and summer made it too wet to grow. In Saskatchewan, Saskatoon measured a record 645 mm (25.39 inches) of rain during April-September, demolishing the previous record by 54 percent. The wheat harvest declined by 15 percent relative to 2009, and the farm economy suffered immensely, with economic losses measured in the billions of dollars.

Atlantic Mayhem

Tropical cyclone activity was well above average in the Atlantic Basin, thanks in part to the El Niño transitioning to a La Niña by July and the resultant reduced wind shear. Warm tropical waters in the Atlantic also buoyed development. The tally of 19 named storms this season was well above the long-term mean of about 11 storms, and the Caribbean region was a magnet for many of the storms.

On July 8, Alex combined with tropical depression 2 in Texas to send the Rio Grande over its banks, closing bridges between the United States and Mexico, as the river widened to several times its normal size.

Flooding also affected large parts of eastern and southern Mexico this year. In July alone, over 400 mm (16 inches) of rain drenched Mexico's east coast. In September, Tropical Storm Karl was blamed for at least eight deaths, as well as the evacuation of 30,000 people. From late August into early September, floodwaters forced some 200,000 people in the state of Veracruz out of their homes.

Also in September, Hurricane Igor's heavy rains set off flooding that covered the streets of Hamilton, Bermuda, with several inches of water, while powerful winds littered the streets with branches and debris. Igor then went on to pound the east coast of Newfoundland on September 20. Winds gusted up to 172 km/h (107 mph) there, and rainfalls exceeding 150 mm (6 inches) broke century-old records. Swollen rivers washed away roads and bridges, isolating over 150 communities. Total damages exceeded $185 million from the storm, which was considered Newfoundland's worst ever. The city of Halifax in Nova Scotia previously had been hit by Hurricane Earl, which battered the city with gusts of 120 km/h (75 mph) and rainfalls exceeding 50 mm (2 inches). The winds stirred up the ocean to a nearly unbelievable state, generating 25-meter (82 feet!) peak waves west of the Scotian Slope. The storm left more than 220,000 customers without power across the Maritimes.

As if Canada had not seen enough tropical fury this year, in early November an upper-level trough and surface front picked up the moisture from Hurricane Tomas and dumped 200 mm (8 inches) and more of rain over western Nova Scotia and southern New Brunswick, causing the worst flooding in a century in some locations.

Earlier, on November 5, Tomas brought landslides and flooding to Haiti, which was still reeling from the earthquake that had struck in January.

Pacific Storms

The average annual number of tropical cyclones in the Western North Pacific (WNP) is 27, dwarfing the mean number of storms in the Atlantic (11). This year a rare event took place, with more cyclones in the Atlantic (19) than in the WNP (preliminarily, 15). This set a record for the fewest number of storms since the satellite era began in the 1970s, and probably for a much longer period.

Caption: This Modis image shows the massive Typhoon Chanthu over China on July 22, 2010.

Caption: This Modis image shows the massive Typhoon Chanthu over China on July 22, 2010.

Tropical cyclone activity was abnormally quiet in the North Pacific across both western and eastern basins, as the Eastern North Pacific tallied only eight cyclones, including three hurricanes, the fewest since at least 1970. In fact, Dr. Ryan Maue at the Florida State University, who compiles data on global cyclones, counted 66 tropical cyclones globally in 2010, the fewest since such records began in 1970.

Nevertheless, several typhoons caused considerable havoc in the WNP this year. The first typhoon of their season, Category 1 Typhoon Conson, struck the northern Philippines on July 13–14. The storm tracked directly over Manila, the capital. Conson was blamed for at least 76 deaths and the loss of electricity by millions of residents. Damaged power lines left over one-half of the northern province of Luzon without electricity. The harsh impact of the storm as it swept across the populated areas of Luzon reportedly surprised forecasters, and the Philippine weather bureau took a lot of heat for the allegedly inaccurate forecasts, including criticism from the highest levels of government (the President).

Category 1 Typhoon Chanthu smashed into Guangdong, in southern China, on July 22, bringing drenching rains to a region already suffering from downpours and flooding that had killed hundreds of people over the preceding weeks. Monsoonal rains to the north over interior China during late July and early August caused additional flooding.

The strongest typhoon of the season, Megi, intensified to Category 5 before making landfall on the east coast of Luzon in the Philippines on October 18. Not only was Megi the strongest cyclone in the Pacific this year, it was the strongest anywhere in the world. Its minimum sea level pressure of 885 mb (26.14 inches) made this one of the strongest storms to ever make landfall. Megi damaged more than 100,000 homes in the northern Philippines and took 28 lives, but it could have been much worse, given Megi's ferocity. The path of the cyclone, which was well to the north of Manila, reduced the damage potential.

Megi veered right in the South China Sea after exiting Luzon, and later made landfall in southern China. Although west of Taiwan, Megi triggered torrential rains and massive rock and mudslides on the island during October 20–22. One slide buried a temple, killing nine, while a rockslide tossed a bus carrying 19 Chinese tourists off a mountainside. The final Taiwan death count, which was not determined until November due to the difficulty of finding the victims' remains, reached 36. Rainfall totals reportedly ranged as high as 114 cm (45 inches) over 48 hours southeast of Taipei.

Caption: The August 2010 Russian wildfires created this massive pyrocumulonimbus cloud.

Caption: The August 2010 Russian wildfires created this massive pyrocumulonimbus cloud.

Unprecedented Heat

Historic heat and drought gripped much of western Russia this year. Dryness was already a problem before the heat struck, and dry soils likely intensified the heat through land-air feedback mechanisms. One of the worst droughts of the past 30 years slashed crop production in Russia and Kazakhstan during the spring and summer, and the accompanying heat wave only made it worse. A vast stretch of cropland extending from western Russia into central Kazakhstan experienced unusual heat and dryness from April into July. Rainfall measuring less than 30 percent of normal extended from the southern Volga District of Russia into northern Kazakhstan. The drought affected winter grains during their susceptible reproductive to filling stages in the spring, as well as spring grains and other crops later on during the summer.

Caption: Volunteers near Roshal (Shatursky district of Moscow region) in Russia cleared debris and extinguished small blazes in the aftermath of last summer's fires.

Caption: Volunteers near Roshal (Shatursky district of Moscow region) in Russia cleared debris and extinguished small blazes in the aftermath of last summer's fires.

The background for the catastrophic weather over Russia and Pakistan in July and August had much to do with the shape and persistence of the jet stream over Asia and the blocking high over northern Russia. The jet stream contorted into a highly amplified pattern that changed little from July into August. A rain-inducing trough over Eastern Europe, a high pressure ridge over western Russia, and a downstream trough extending into Pakistan contributed to flooding in central Europe, heat and drought in western Russia, and the monsoonal flooding over Pakistan.

June temperatures were already unusual, averaging at least 3°C (5°F) above normal from western Russian eastward into Kazakhstan. As the blocking high strengthened, nearly all of western Russia from the Urals to Scandinavia sweltered as July temperatures averaged 5 to 7°C (8–11°F) above normal, obliterating previous monthly records. Moscow's July 2010 temperature exceeded the long-term mean by 7.8°C (14°F) and broke the previous record, set in July 1938, by a remarkable 2.5°C (4.5°F). This was the hottest month in at least 130 years in Moscow.

The core of the heat persisted from July 22 to August 11, when Moscow thermometers rose to at least 32°C (90°F) on every day but two. The worst of the heart wave took place from July 22–29, when maximum daily readings rose to at least 35°C (95°F). For the first time in Moscow, the thermometer hit 37.5°C (100°F) on July 26. This record was equaled just two days later and, on July 29, the heat wave peaked as the maximum temperature rose even higher to 38.2°C (101°F). Given that the normal high temperature is just 22°C (72°F), this means temperatures reached 16°C (29°F) above normal. For comparison purposes, the equivalent departure in Washington, D.C. would result in a Mojave Desert-like 48°C (119°F)!

Extreme heat began earlier in southern parts of Russia, and the city of Yashkul, on the Kazakhstan border, set the all-time record for the country on July 11 (44.0°C, 111.2°F). A number of countries in the Middle East also established all-time records in June or July, including Iraq on June 14 (52.0°C, 125.6°F, in Basra).

The heat and dryness sparked thousands of fires in Russia, including peat bog fires near Moscow. More than 50 people died directly from the fires, which destroyed more than 2,000 homes. A pall of smoke and smog hung over Moscow during the first week of August, doubling the city's death rate. Swiss Re blamed the heat in Russia for 15,000 deaths, which would easily make this the deadliest weather disaster of the year, and the deadliest heat wave since the European heat wave of 2003.

Unprecedented Flooding

Caption: A washed-out bridge, damaged from flooding in late July 2010, is shown in Pakistan.

Caption: A washed-out bridge, damaged from flooding in late July 2010, is shown in Pakistan.

The same time that Moscow residents were coping with their hottest weather, an historic monsoon deluge began in northern Pakistan, leading to catastrophic flooding of the Indus River and its tributaries.

The combination of the upper level trough, low surface pressure over Pakistan, and a strong inflow of moisture from the Bay of Bengal made conditions ripe for catastrophic rainfall in the north during the last days of July. A number of locations in Punjab and Khyber Pakhtunkhwa measured over 300 mm (12 inches) of rain on July 28–30. Peshawar, for example, saw 333 mm (13.11 inches) on July 29–30, and other locations reported up to 401 mm (15.79 inches). The ground was already wet from heavy rains that fell during July 19–22, so the rivers rose rapidly and quickly shot out of their banks. Flooding affected the north initially, but heavy August rains produced another surge of floodwaters that inundated the south as well. At one point, about one-fifth of Pakistan was under water. The scope of the flooding, considered the worst on record, was almost beyond comprehension, as over 1,700 people died, nearly 3,000 were injured, more than 1.3 million were rescued, and 6 million were displaced. Floodwaters damaged or destroyed more than 1.89 million homes. Both infrastructure and agriculture suffered extensive damage. Wheat crop damage has been estimated to be over $500 million, and damage to structures exceeded $4 billion.

Many other parts of the world experienced flooding this year, with China especially hard hit. June rainfall exceeded twice normal over parts of southern China, and many locations picked up over 400 mm (16 inches) of rain. Several hundred people died as a consequence of flooding. In July, heavy rains and flooding affected central China farther north. In August, a broad area from the North China Plain into Korea experienced rainfall twice the norm.

The western portion of the swath of excess moisture included the mountainous Gansu Province. Torrential rainfall triggered a massive mudslide on August 8 that tore through the city of Zhouqu in Gansu, obliterating everything in its path. A surge of mud, water, and rocks up to five stories high claimed 1,471 lives, with another 294 missing and assumed dead.

Australian Floods

Caption: Flash flooding in the intersection of Spencer and Flinders Streets during the 2010 Melbourne thunderstorms.

Caption: Flash flooding in the intersection of Spencer and Flinders Streets during the 2010 Melbourne thunderstorms.

Australia also experienced historic flooding this year. Major flooding occurred in late February and early March in Queensland, and a severe hailstorm on March 6 in Melbourne caused some $1 billion in damages.

But these events were overshadowed by the extensive flooding that overran much of Queensland in December, lasting into January 2011. Both Queensland and New South Wales experienced their wettest spring (September-November) on record, so the stage was set for historical flooding when over 400 mm (16 inches) of rain fell in December. This was the wettest December both for Queensland and also for eastern Australia as a whole.

Fueled by the circulation associated with Tropical Cyclone Tasha, which made landfall in Queensland on Christmas Day, the bout of heavy rains that struck eastern Australia during December 23–28 made an already bad situation even worse, as rainfall exceeded 400 mm (16 inches) during the six-day period in some locations. Floodwaters in Queensland inundated thousands of properties, while numerous rivers throughout the region reached record levels. Military aircraft dropped supplies to towns cut off by floodwaters, which covered an area larger than France and Germany combined. Damage to property, infrastructure, and agriculture was estimated to run to several billion dollars. The extent, severity, and impact of the flooding, which affected parts of New South Wales as well as Queensland, made this the most significant flooding disaster in Australia since at least the 1970s.

In South America, heavy rains in 2010 ended drought in the north, but the southern Amazon Basin experienced far below-normal rainfall every month from June through September, leading to one of the two worst Amazon droughts in recent decades. In September, the Amazon River's depth at Manaus, Brazil, the main city on the Amazon, fell to its lowest level since 1963. The low water levels crippled transportation and fishing, as well as causing millions of fish to die and leading to shortages of fresh water. The drought appeared to be even more severe than the drought of 2005, which many considered a once-in-a-century event at that time.

Snowmageddon in Europe

The moderate to strong La Niña that intensified during the last half of 2010 had a hand in Australia's extreme wetness, as well as persistent wetness across Indonesia to the north. But the return of a negative Arctic Oscillation/North Atlantic Oscillation (AO/NAO) circulation pattern in November played a role in a replay of January's extreme wintry weather in Europe.

Heavy snows and frigid cold brought chaos to Europe from late November through December. Snow caused Gatwick Airport outside of London to shut down operations on December 2–3, and at least 6,500 schools closed across the UK. Parts of eastern Britain measured snow depths up to 70 cm (28 inches). Another snowstorm on December 18 shut down busy Heathrow Airport for a time, and major delays disrupted other European airports, leaving thousands stranded across Europe just days before Christmas. This was the UK's coldest December on record, with temperatures averaging 5°C (8°F) below normal. Insurance claims from the freezing weather in December totaled $2.2 billion.

Warm Year Anyhow

Despite the cold start and end to the year in the U.S. and Europe, as well as the ongoing La Niña during the last half of the year, with its accompanying cold Pacific waters, the various global temperature time series were all in agreement: 2010 was in a statistical tie with 1998 and 2005 as the warmest year in the entire instrumental record. Coolness over parts of northern Europe and Australia was more than offset by the exceptionally warm year over much of Africa, southern and western Asia, Greenland, and Arctic Canada, not to mention the record summer heat in Russia and the U.S. The satellite record was consistent with the thermometer record, showing 2010 in a statistical tie with 1998 as the warmest year. Looking at the decade that just ended, global temperatures were the highest for any 10-year period since such records began more than a century ago.

Top 10 International Weather Events for 2010

  1. Russia Heat Wave. The most extreme heat in at least 130 years gripped Russia in July and August. Heat and dryness sparked thousands of wildfires and decimated crops, while the heat, smoke, and smog were blamed for as many as 15,000 deaths.

  2. Pakistan Flood. Epic and unprecedented flooding inundated one-fifth of Pakistan during July-August, killing over 1700 people and displacing 6 million.

  3. Australia Flood. Record December rains in Queensland triggered Australia's worst flooding in over 30 years. Floodwaters inundated thousands of properties, cutting off towns and villages, requiring aircraft drops of food and supplies.

  4. China Landslide. Torrential rains in northwest China triggered a massive landslide that left over 1700 people dead in the city of Zhouqu. Several bouts of flooding elsewhere this summer caused numerous fatalities and major property damage in China.

  5. Super Typhoon Megi. Megi, one of the most severe tropical cyclones to ever make landfall, struck the northern Philippines as a Category 5 typhoon on October 18. The storm damaged more than 100,000 homes in the Philippines, and later went on to cause deadly rockslides in Taiwan.

  6. Mexico Flooding. In eastern and southern Mexico, flooding from Hurricane Karl and other tropical cyclones, as well as heavy seasonal rains, forced more than 200,000 residents from their homes during July-September.

  7. European Cold and Snow. Severe cold and snow brought chaos to Europe in December, stranding thousands of passengers in airports just before Christmas.

  8. Winter Storm in Europe. A severe winter storm sporting hurricane-force winds struck the French coast on February 28, killing 63 people and causing at least $2.8 billion of damage in France, Spain, and Portugal.

  9. Amazon Drought. The Amazon Basin endured one of its worst droughts in the past 47 years due to persistent lack of rain from June to September. The Amazon River reached its lowest levels since 1963.

  10. Record Few Tropical Cyclones. Despite several landfalling typhoons, the Western North Pacific and the Eastern North Pacific saw the fewest numbers of named storms on record, contributing to the lowest count of global cyclones in at least 40 years.

Weatherwise Contributing Editor DOUGLAS LECOMTE is a retired meteorologist formally with NOAA's Climate Prediction Center in Camp Springs, Maryland.

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