Updated 08 June 2010
As of May 25th, 25.1 percent of the Hawaiian Islands—confined to the leeward portions of Hawaii's Big Island, Maui, and Molokai—was experiencing extreme to exceptional drought conditions, as defined by the U.S. Drought Monitor. The dry conditions led to a large brush fire in the Olowalu area of West Maui on May 3rd, forcing about 100 residents to evacuate their homes. The fire scorched an estimated 1,100 acres but was 90 percent contained by May 8th, according to Maui fire officials (Source: Hawaii News Now).
While much of southern China was relieved of dry conditions after receiving heavy rainfall during late April and May, Yunnan province remained entrenched in its worst drought in more than a century. Between September 2009 and early May 2010, rainfall was 60 percent below normal. More than eight million people lacked adequate drinking water and crop losses to date were estimated at 2.5 billion U.S. dollars (Source: Nature).
The El Niño weather pattern during fall 2009–spring 2010 led to extreme dryness in Guam and all of Micronesia. While drought is common during Guam's dry season (January–June), as of the end of May the island was experiencing its worst drought since 1998. Guam recieved only 0.74 inches (19 mm) of rain in May, compared with the average of 5.4 inches (137 mm), while temperatures were above normal during much of the month (Source: Pacific News Center; WERI).
A high pressure system over much of east-central North America brought a heat wave to large areas of the central, northern, and northeastern U.S. and Ontario and Quebec, Canada on May 23rd–26th. In the U.S., hundreds of daily high maximum and high minimum temperature records were broken across Indiana, Illinois, Iowa, Wisconsin, Michigan, and Minnesota on the 24th and 25th. In Minneapolis, Minnesota, the temperature soared above 90°F (32°C) on the 24th, breaking the previous record of 88°F (31°C) set on this date back in 1875. On May 25th, the towns of Timmins and Kapuskasing in northwestern Ontario each experienced their warmest May temperature since records began in 1955 (Source: Environment Canada). The temperature reached 94.3°F (34.6°C) in Timmins, which is 28.1°F (15.6°C) above normal for this time of year. By the 26th, the heat wave shifted eastward and hundreds of additional temperature records were broken, particularly across New York, Pennsylvania, New Hampshire, and Vermont, along with many other areas farther to south and southwest.
Prior to the onset of the Southwest Monsoon rains, northern India and Pakistan baked as a heat wave scorched the region near the end of May. The Pakistan Meteorological Department reported record temperatures for several days during the last week in May. A maximum temperature of 128.7°F (53.7°C) was recorded in Mohenjo-daro on May 26th. This was the warmest temperature ever recorded in Pakistan and possibly the fourth warmest temperature ever recorded anywhere in the world (Source: The Guardian). On the 27th, the maximum temperature in the city of Multan in Punjab Province reached 122°F (50°C), breaking the old record of 120°F (49°C) previously set in 1956. Temperatures were also well above normal in India—the highest in more than 50 years (Source: Buzzle). The temperature reached 120°F (49°C) on May 26th in Jalgaon in Maharashtra state while India's capital city, Delhi, topped out at 113°F (45°C) (Source: BBC news). At least 18 people died in Pakistan and more than 260 perished in India due to the heat, according to local media reports (Source: The Guardian; PakTribune). This was the first extreme heat wave to hit the Pakistani region since 1998.
In the midst of Kenya's first rainy season of 2010, which runs from March–May, weeks of heavy rains culminated in floods and mudslides that killed at least 93 people and destroyed thousands of acres (hectares) of crops (Source: IRIN). Mudslides have become more commonplace as more forests have been cleared to make way for farming. The flooding is the worst to affect Kenya in more than a decade (Source: BBC News).
A storm system that stagnated over the Lower Mississippi Valley on May 1st–2nd killed 29 people and flooded thousands of homes and businesses. The storms spawned dozens of tornadoes and brought record amounts of rain to numerous locations in Mississippi, Tennessee, and Arkansas. Preliminary reports indicated that more than 200 daily, monthly, and all-time precipitation records were broken across the three states. According to the National Weather Service, Bowling Green, Kentucky set an all-time daily rainfall record for May of 4.75 inches (120 mm) on May 1st. However, that record was broken the following day as 4.92 inches (125 mm) of precipitation was recorded. The combined total of 9.67 inches (246 mm) was the greatest two-day rainfall total for the area since records began in 1870. In Nashville, the most rain ever recorded in a single calendar day fell on May 2nd—7.25 inches (184 mm)—making the precipitation received on the previous day (6.32 inches or 161 mm) the third-greatest rainfall total in Nashville's history. This led to a record two-day total of 13.53 inches (344 mm), more than doubling the previous record of 6.68 inches (170 mm) received from the remnants of Hurricane Fredrick on September 13th–14th, 1979. By just the second day of the month, Nashville had already recorded its wettest May on record and fifth wettest month ever. The torrential rains caused several rivers to crest at record levels. According to a local U.S. Geological Survey official, the flows on various rivers in the Nashville area exceeded those from the historic 1927 and 1975 floods. The Cumberland River in Nashville crested at 51.85 feet (15.80 m) on May 3rd, nearly 12 feet (3.7 m) above its flood stage—the highest level since an early 1960s flood control project was built (Source: AP). The Duck River in Centerville, Tennessee crested at 47.5 feet (14.4 m), smashing the old record of 37 feet (11.7 m) set in 1983. Fifty-two of Tennesse's 95 counties were declared disaster areas by the governor, as were 73 of Kentucky's 120 counties. Preliminary estimates placed damages at more than 1.5 billion U.S. dollars (Source: BBC News).
Heavy rains in northern Afghanistan and southern Tajikistan during the first week in May caused major flooding, killing at least 124 people and leaving thousands of families homeless. About ten thousand cattle were lost and thousands of acres (hectares) of agricultural land were ruined due to the floods (Source: Relief Web). While springtime flooding is common in the region, Tajikistani officials were surprised by the magnitude of the event (Source: AP).
On May 16th–17th, up to eight inches (200 mm) of rain fell over southern Poland and the Czech Republic in a 24-hour period (Source: Reuters). The rains and subsequent overflowing rivers brought the worst flooding in more than a decade to Poland, killing at least 20 people and forcing thousands to evacuate their homes. Poland's prime minister stated that damages could reach three billion U.S. dollars (Source: Reuters). While Poland received the brunt of the storm damage, the Czech Republic, Slovakia, Hungary, and Serbia also experienced flooding and were majorly affected. Wind speeds of 65 mph (110 km/hr) were reported north of Budapest, Hungary.
From May 14th–28th, monsoonal rains, in combination with heavy rain bands from Tropical Storm Laila, led to the worst flooding in Sri Lanka in five decades (Source: International Federation of Red Cross). On the heels of Laila, the Southwest Monsoon began to develop over the island on May 21st and stalled for several days due to the effects of the tropical storm. At least 20 people were killed and more than 500,000 were affected by the devastating floods, particularly in southern, western, and central parts of the country.
On May 16th, heavy rains in the eastern Democratic Republic of Congo triggered a mudslide 13 feet (4 meters) deep and 165–490 feet (50–150 meters) wide on the slopes of Karisimbi volcano that tore through the village of Kibiriga at more than 30 mph (50 km/hr). Nineteen people were killed and 27 left unaccounted for. At least five other mudslides similar in magnitude have occurred in the area since the 1950s (Source: AFP).
A slow-moving severe storm system brought record rainfall and flooding and spawned several tornadoes in Mississippi, Tennessee, Arkansas, and Kentucky in the Lower Mississippi Valley on May 1st–2nd. Forty-five tornadoes touched down during this time period, according to preliminary reports by NOAA's Storm Prediction Center. One person was killed in Arkansas by an EF-3 tornado packing winds of 145 mph (233 km/hr). Initial damage was so great officials declared a state of emergency.
On May 2nd, at least 17 people were killed and 50 injured by lightning strikes as hailstorms and heavy rains pounded Bangladesh (Source: AFP). On May 8th, strong thunderstorms and torrential rains killed at least 43 people in northern India. Trees were uprooted and hundreds of homes were lost (Source: AFP). Severe storms are common prior to the onset of the monsoon season in June.
Torrential rains accompanied by gale-force winds and a tornado swept through the southwestern Chinese municipality of Chongqing on May 5th. More than six inches (157 mm) of rain fell over a 24-hour period, according to the China News Service. At least 70 people were killed and more than 190 were injured. A local official in Liangping county—one of the hardest-hit areas—said that this was the first time a tornado was ever reported in this region (Source: AFP). Storms continued through the month in southern China. By the end of May, an additional 45 people were reportedly killed by severe storms and flooding. In total, the storms affected an estimated 10 million residents across 13 provinces and cities in southern China, according to the State Flood Control and Disaster Relief Headquarters website. This year's flood season began one month earlier than normal and was attributed to the El Niño phenomenon by China's National Meteorological Center (Source: Xinhua News Agency).
Two people were killed and at least 58 others were injured as a violent weather system spawning dozens of tornadoes and baseball-size hail tore across Oklahoma and Kansas on May 10th. Widespread damage and destruction caused Interstate 40—a major east-west transportation route—to close, backing up traffic for miles (Source: AP). For more information, please see NCDC's May 2010 Tornado Report.
The first tropical cyclone of the 2010 North Indian Ocean hurricane season formed in the Bay of Bengal on May 17th. Spanning hundreds of kilometers in diameter, Laila became a Category 1 tropical cyclone on May 19th with maximum sustained winds of 75 mph (120 km/hr). Affecting both Sri Lanka and India, the storm made landfall on the 20th near Bapatla, Andhra Pradesh in southeast India. This is the first May storm to affect the southeastern portion of the country in two decades. At least 56 people in India were killed and 75,000 displaced as heavy rains and strong winds battered the coast.
Tropical Storm Agatha—the first named storm of the 2010 Pacific hurricane season—formed off the west coast of El Salvador on May 29th. The storm made landfall near the Guatemala–Mexico border that same day. Although the storm only intensified to sustained winds of 45 mph (72 km/hr), the slow-moving system dumped up to three feet (almost one meter) of rain in parts of Guatemala, according to government officials. One of the deadliest Pacific tropical cyclones on record, at least 184 people were killed in Guatemala, El Salvador, and Honduras (with most of the deaths concentrated in Guatemala) and more than 165,000 were evacuated from their homes. All three countries declared states of emergencies. A large sinkhole more than 60 feet (18 meters) wide and 200 feet (60 meters) deep formed in the middle of Guatemala City, swallowing a street intersection and a three-story clothing factory. For Guatemala, this was the second disaster to occur within a short period of time. On May 27th, Pacaya volcano erupted for the first time in more than a decade, spewing ash and debris for miles, killing three people, and forcing hundreds to flee their residences. The Gualtemala City airport—the third largest airport in Central America— closed on May 27th for several days as it was covered with ash up to three inches (80 mm) deep (Source: AP).