| A |
| Air Masses | A large area of air with common characteristics: temperature, air pressure, and moisture. |
| Air Pressure | Pressure caused by the weight of the air |
| Astronomical conditions | Conditions in the earth's atmosphere. In tidal waves, when the sun and moon line up, their combined gravity causes higher than normal waves. |
| Atmosphere | The layer of gases that surrounds the earth: oxygen, nitrogen, carbon dioxide and other gases. |
| Atypical | Not typical or usual. |
| Avalanche | A swift sudden landslide of snow, ice, rocks, or dirt down a mountain slope. |
| B |
| Blizzard | A blinding snow storm with a very strong, cold wind. |
| C |
| Climate | The average weather conditions of a region including: temperature, rainfall, humidity, and wind conditions. |
| Clouds | A white or gray or almost black mass in the sky made up of tiny drops of water or ice crystals. |
| Condensation | The changing from a gas or a vapor to a liquid. |
| Contamination | Something that is spoiled by dirt, disease, or bacteria. |
| Coriolis | The earth's rotation causes air to move in a circular motion. |
| Crystals | Regularly shaped pieces with angles and flat surfaces. |
| Cumulonimbus | A cloud that often has heavy precipitation, and can lead to thunderstorms or tornadoes. |
| D |
| Doldrums | An area near the equator that has little or no wind. |
| Dredge | A method used to deepen harbors and waterways. |
| Drought | A long period of time without rainfall. |
| E |
| Earthquake | A movement of a portion of the earth's crust produced by underground volcanic forces or by breaking and shifting of rock beneath the surface. |
| Equator | An imaginary circle around the center of the earth. |
| Evacuate | To withdraw or leave, especially from a threatened area. |
| Evaporate | To change from liquid to a vapor. |
| Eye | The calm center of a hurricane. |
| F |
| Flood Zone | An area prone to floods. |
| Fujita-Pearson-Scale | A scale used to rate a tornado's power. |
| H |
| Hail | Small pieces of ice coming down from the clouds in a shower, frozen rain. |
| Heat Index | A large amount of moisture in the air makes a warm day feel even warmer. |
| Humidity | Dampness or moisture - the amount or degree of moisture in the air. |
| Hurricane | A violent cyclone with winds moving from 70 to 100 miles an hour, usually accompanied by rain, thunder, and lightning: hurricanes generally form in the tropics |
| K |
| Kilometer | A unit for measuring length or distance (about 5/8 of a mile) |
| L |
| Levee | An embankment raised to prevent a river from over flowing |
| M |
| Monsoon | A southwest wind that brings heavy rains and flooding |
| P |
| Phenomenon | A fact, event or circumstance that can be observed or sensed |
| Polar Easterlies | A wind that blows from the North and South poles in an easterly direction |
| Precipitation | The water that falls to the earth in the form of rain, snow, sleet, or hail |
| Prevailing Westerlies | A wind that blows in a westerly direction. It is also called the Trade Winds |
| S |
| Saffir Simpson Scale | A scale used to measure hurricanes |
| Season | The average temperature is different in each season. In most of the U.S. there are four seasons: winter, spring, summer, and fall |
| Shelter | Something that covers or protects |
| Snow | Soft white crystals of ice that fall to the earth as precipitation |
| Storm Surge | A large wave caused by a hurricane |
| Structure | A building; anything that is built |
| T |
| Tidal Wave | Often the name incorrectly identifying a tsunami; tidal waves are the extremely long period waves driven by the forces producing the tides. 1. The wave motion of the tides. 2. In popular usage, any unusually high (and therefore destructive) water level along a shore. It usually refers to either a storm surge or tsunami. |
| Tronada | A Spanish word for tornado |
| Tropical | Having to do with the warm regions of the Earth near the Equator |
| Tropical Easterlies | Air from the equator warms and rises. As it cools, it flows back down to the equator. It is forced in an east to west flow due to the rotation of the earth. |
| Tsunami | A very large and destructive ocean wave caused by an underwater earthquake |
| U |
| Updraft | A surge of air in an upward direction |
| UTC | Universal Coordinated Time: same as Greenwich Mean Time; uniform atomic time system kept very closely to UT2 by offsets. Maintained by the US Naval Observatory. GPS time is directly relatable to UTC. UTC-GPS = 9 seconds (in 1994) |
| W |
| Water Vapor | Water in the form of mist or tiny droplets in the air |
| Wind Chill Effect | When wind flows, it makes the temperature feel cooler. In winter, it can lower the temperature to dangerous levels. In 1999, record lows of -100 degrees (wind chill) were recorded in Alaska. |
