Air Pressure: Air pressure affects the boiling point of water, with boiling occurring at lower temperatures the higher one goes. Air moves from areas of high atmospheric pressure to areas of lower pressure. In an area of high pressure, the air molecules are closer together than they are in an area of lower pressure. Air molecules tend to move from high to low pressure, and it is this movement of air that we feel as wind. The greater the difference tween the two pressures, the stronger the wind will be.
Avalanches: Avalanches are a major, unrecognized, weather-related hazard. A leading cause of winter recreation fatalities in the western United States, a typical avalanche unloosens some 100,000 tons of snow!
Blizzards: The Great Blizzard of 1993 was so powerful a storm that it set record-low barometer readings over a dozen states.
Clouds: Clouds are made of trillions of tiny droplets of water (or when cold enough, ice crystals).
Droughts: At least in the modern era, the 1988 drought in the United States was among the most severe on record. In parts of the Midwest, it was so dry that during thunderstorms rain evaporated before reaching the ground, and lightning set fire to people's lawns.
Earthquakes: The most intense large urban area earthquake in recorded history occurred in Lisbon, Portugal, on November 1, 1755 and may have registered a magnitude of at least 9.0 on the Richter scale. The first series of shocks lasted 6 or 7 minutes. The city was virtually leveled. Over 60,000 people died. The quake was felt as far away as Sweden and the giant tsunami wave it generated swept much of the North Atlantic, with waves of twelve feet striking the West Indies.
El Nino: The longest recorded period for El Nino, which typically lasts about 12 to 18 months, lasted from 1991 to 1995, a period marked by numerous weather disasters worldwide. Evidence suggests such long lasting El Ninos should occur only every several thousand years.
Floods: While 1992 will be long remembered as the "Year of Hurricane Andrew," that violent storm took far fewer lives than flooding did. At least 87 flood-related deaths were reported in the United States in 1992. Over the last three decades, our nation's annual death toll from flooding has been 138 compared to only 27 for tropical storms.
Humidity: The most humid place in the world is the Ethiopian coastline along the Red Sea. When the dew point (the temperature at which the moisture in the air would condense if cooled at constant pressure) passes 70 degrees Fahrenheit, most people find the air oppressively sticky. Rarely does the dew point top 80 degrees Fahrenheit in the United States. But, along the Ethiopian Red Sea coastline, the June dew point average is 84 degrees Fahrenheit.
Hurricanes: According to one estimate, a hurricane's energy output can be rated on the order of 100 billion kilowatt hours each day. La Nina : La Nina is the opposite of El Nino, referring to a period of cold surface waters in the Pacific Ocean.
Lightning: The air in the core of a lightning bolt has been estimated to be heated to as much as 54,000 degrees Fahrenheit. That happens to be about six times hotter than the surface of the sun!
Pollution: In October 1948, in the valley town of Donora, Pennsylvania, about 30 miles south of Pittsburgh, a stagnant air mass allowed pollution levels to build. Half the population of 14,000 became ill, and 20 people died. A similar disaster struck the Meuse River Valley in Belgium in 1930 when 30 people died and thousands more were made ill.
Snow: If the elevation is high enough, it can snow on the equator. Snow falls regularly in the Andes Mountains of Ecuador, in fact. In the heart of central Africa, Mt. Kilimanjaro and Mt. Kenya are frequently snowcapped. Even in tropical regions, the freezing level of the atmosphere is rarely higher than 20,000 feet.
Temperature: The highest temperature ever recorded on Earth was in Libya. The temperature in the Libyan desert was once officially measured at 136 degrees Fahrenheit.
Thunder: A clap of thunder can typically register about 120 decibels, which is ten times louder than a garbage truck, chain saw, or pneumatic drill. In comparison, sitting in front of the speakers at a rock concert can expose you to a nearly continuous 120 decibels, which can seriously harm your hearing.
Tidal Waves: The lack of sand dunes near the oceanfront in New South Wales, Australia, has prompted a theory that they may have been washed away by a giant tsunami (tidal wave). Some 100,000 years ago a wave, possibly a quarter-mile high at its presumed origin in a Hawaiian earth slide, swept across the Pacific and scoured the coastline clean.
Tornadoes: The worst single tornado tragedy in the United States was the Tri-State (Missouri, Illinois, and Indiana) tornado outbreak of March 18, 1925. Several tornadoes claimed a total of 747 lives with an additional 2,027 persons being injured. The largest of these twisters killed 695 persons, the worst single tornado death toll ever.
Volcanoes: The deadliest volcanic disaster since the eighteenth century occurred in Mt. Tambora, Indonesia, on April 5, 1815. 92,000 people died.