December 12, 2013

The cold temperatures currently griping most of the United States have nothing on the coldest temperature ever registered on Earth—a skin-freezing, bone-numbing, lung-paralyzing -135.8 °F (-93.2 °C) recorded on August 10, 2010, in Antarctica. That’s 50 degrees colder than any temperature ever measured anywhere in Alaska or Siberia, according to Ted Scambos, the lead researcher on the team that announced the shivery record. It’s even lower than the coldest official temperature recorded on Earth, also found in Antarctica. The average low temperature in Antarctica in July, the height of winter, is about -81 degrees °F (-63 °C).

Scambos, a senior research scientist at the National Snow and Ice Data Center in Boulder, Colorado, and his team identified the temperature extreme while producing the most detailed global-surface temperature maps ever created. The maps are based on thermal radiation readings—that is, the amount of heat given off at the surface—made by Earth-orbiting satellites operated by NASA and the National Oceanic and Atmospheric Administration. The data go back some 30 years.

Antarctica is colder than the icy region of the Arctic Ocean centered on the North Pole. Temperatures in Antarctica almost never rise above 32 °F (0 °C). (© Rod Planck, Photo Researchers)

The record cold temperature was measured in one of a number of “pockets” in the snow between two summits on the Eastern Antarctic Plateau. Scamos and his team aren’t completely sure why these flat areas are colder than areas downhill. As air chills, it usually grows denser. The scientists had expected that the denser air would have slid down the hill to collect at the bottom. But that’s not what has happened. Perhaps, they speculated, the higher-pressure air at the bottom is actually pushing upward, preventing the colder air from coming down. Stuck in place, the air in the pockets keeps getting colder and colder and colder.

Unfortunately, the new measurement won’t qualify as the coldest official temperature ever recorded on Earth. That record, which has stood for more than 30 years, is -128.6 °F (-89.2 °C), taken at the nearby Vostok weather station in July 1983. For official certification, the World Meteorological Organization requires temperature measurements to be taken 6.5 feet (2 meters) above the surface, not at the surface. But Scambos stands by his new record. “I’m confident these pockets are the coldest places on Earth. I wouldn’t be here if I wasn’t pretty sure we were colder than Vostok.”

Meanwhile, the U.S. National Weather Service offers the following advice for staying safe in frigid temperatures:
The best way to avoid hypothermia and frostbite is to stay warm and dry indoors. When you must go outside, dress appropriately. Wear several layers of loose-fitting, lightweight, warm clothing. Trapped air between the layers will insulate you. Remove layers to avoid sweating and subsequent chill. Outer garments should be tightly woven, water repellent, and hooded. Wear a hat because much of your body heat can be lost from your head. Cover your mouth to protect your lungs from extreme cold. Mittens, snug at the wrist, are better than gloves. Try to stay dry and out of the wind.

Additional World Book articles:

• First aid (Frostbite)
• Remote sensing
• Hot and Cold: Staying Healthy in All Weather (a Special Report)

May 16, 2013

Rescue workers are searching for survivors in a destroyed subdivision in Granbury, Texas, which was mowed down in the night by a mile-wide tornado. At least 6 people people are known to be dead and 37 others injured. A tornado flattened at least 50 houses in another subdivision a few miles southeast of Granbury. Granbury is about 35 miles (56 kilometers) southwest of the Dallas-Fort Worth metropolitan area.

The U.S. National Weather Service has confirmed that as many as 10 tornadoes swept through towns south of Fort Worth during the night.

A tornado’s winds can swirl at speeds of hundreds of miles or kilometers per hour, hurling debris in all directions. (© Gene & Karen Rhoden, Peter Arnold Images/photolibrary)

Additional World Book articles

• The Forecast: Better Weather Prediction Ahead (a special report)
• Twisted-More Terrible Tornadoes (a special report)

July 11, 2012

The average temperature across the continental United States for the first six months of 2012 was the warmest on record, announced the National Oceanic and Atmospheric Administration on July 9. The 12-month period ending on June 30 was also the warmest on record in the 48 contiguous states. Record keeping was begun by the National Weather Service in 1895. The average temperature through June–57.4 °F (14.1 °C)–is 4.5 degrees higher than the long-term average for the same period. In Colorado, the average temperature in June was 6.4 degrees higher than the historical average.

High temperatures in the second half of June broke or tied records in 173 locations across the nation. The temperature hit 115 °F (46.1 °C) on June 26 in Red Willow, Nebraska, breaking the 114 °F (45.5 °C) record set in 1932. The temperature reached an all-time high of 118 °F (47.7 °C) on June 28 in Norton, Kansas.

High temperatures in June contributed to a record-warm first half of the year and the warmest 12-month period the United States has experienced since record keeping began in 1895. (National Oceanic and Atmospheric Administration)

The first six months of the year were also drier than usual, with total precipitation 1.62 inches (4.11 centimeters) below average. According to the Weather Service’s weekly Drought Monitor, 56 percent of the nation experienced drought conditions in June.

The unusually high temperatures and drought conditions created ideal conditions for wildfires. Wildfires burned across 1.3 million acres (526,000 hectares) in the western United States in June alone.

Additional World Book article:

• Weather
• The Forecast: Better Weather Prediction Ahead  (a special report)
• When the Rain Stops (a special report)
• Weather 1932 (a Back in Time article)

July 6, 2012

Drought conditions are present in 56 percent of the continental United States, the National Weather Service announced on July 5. The prolonged heat wave across the Midwest is not only setting record high temperatures, it is expanding and intensifying drought conditions. “This year the high temperatures have certainly played into this drought,” noted Brad Rippey, a meteorologist with the U.S. Department of Agriculture. “There’s a lot more evaporation . . . and crop demands for water.”

Corn stunted by lack of rain (courtesy of AP/Wide World)

According to the Weather Service’s weekly Drought Monitor, the drought is starting to “take a significant toll” on food supplies. . . . “In the primary growing states for corn and soybeans, 22 percent of the crop is in poor or very poor condition, as are 43 percent of the nation’s pastures and rangelands and 24 percent of the sorghum crop.” The extreme heat has taken an especially high toll on corn crops, driving up prices. The ongoing drought is also forcing ranchers in the West to ship cattle to market, driving down beef prices.

Additional World Book article:

• When the Rain Stops (a special report)

July 2, 2012

Some 3 million residents in the mid-Atlantic region of the United States were left without electric power after a series of extremely violent storms downed hundreds of trees and power lines late on June 29. At least 17 people were killed, most of them by falling trees. The National Weather Service described the storm system as a derecho, a fast-moving band that can produce hurricane-force winds. The crescent of storms swept down from Indiana and Ohio, across the Appalachians, and into the mid-Atlantic states, causing particually widespread damage in Virginia, the District of Columbia, and Maryland.

On June 29, a huge region of the United States from the Midwest to the Southeast had record-setting high temperatures: 104 °F (40 °C) in Raleigh, North Carolina, and Washington, D.C.; and 109 °F (42.7 °C) in Nashville, Tennessee, and Columbia, South, Carolina. The 104 °F temperature was the hottest June day in the nation’s capital in 142 years of record keeping.

A derecho is a widespread, long-lived windstorm associated with a line of thunderstorms. A derecho can sometimes last for more than a day and blow across a distance of several hundred miles. (© Jim Reed, Corbis)

As the hot air rose, it clashed with a cold front, giving birth to violent thunderstorms. Fueled by the heat and powered by roaring upper level winds, the storms grew in intensity as they moved southeast. Winds of 72 miles (115 kilometers) per hour were clocked in Fredericksburg, Virginia, and 80 miles (128 kilometers) per hour in Ft. Wayne, Indiana. Meteorologists believe that this derecho is likely to go down as one of the worst on record along its entire path, from northwest Indiana to the Jersey shore. Derechos are most common in the Midwest and Great Lakes region between May and July.

Additional World Book articles:

• Weather
• The Forecast: Better Weather Prediction Ahead (a special report)

March 1, 2012

A powerful storm system that spawned multiple tornadoes from Nebraska to Kentucky early on February 29 smashed parts of the Midwest, causing widespread damage in Kansas, Missouri, and Illinois. Much of the small eastern Kansas town of Harveyville was left in rubble. In the Ozark resort city of Branson, Missouri, a tornado ripped roofs off hotels and damaged some of the city’s famed music theaters. Storms left at least 13 people dead, 6 of them in the southern Illinois town of Harrisburg. A tornado leveled much of that community of 9,000 people.

A tornado's winds can swirl at speeds of hundreds of miles or kilometers per hour, hurling debris in all directions. © Gene & Karen Rhoden, Peter Arnold Images/photolibrary

According to the National Weather Service, the tornado that touched down in Nebraska caused little damage. It was, however, the first known twister ever to hit that state in the month of February.

Additional World Book articles:

• Safety (During a tornado)
• Storm