Date: 1/27 (A) and 1/28 (B) Outcome: Students will understand that weather is a result of complex interactions of Earth's atmosphere, land and water, that are driven by energy from the sun. Question: How does weather influence daily life? Activities: DO NOW! Make an SJ entry for E50 Weather Effects. Galileo Testing in Mac Lab (Take book and SJ with you.) Read E50 on pages E-4 to E-7 / info on extreme weather: floods, hurricanes, tornadoes. In SJ entry, answer E50 AQ #3 from page E – 8 Collect Plate Boundaries Essay Video “Learning About Water” from MediaCast (12:25) Homework: any unfinished work

Floods Floods can happen at any time, almost anywhere in the United States. Floods can result from a single heavy rainfall, days of moderate levels of rain, melting of snow and ice, the breaking of a dam or levee, and even ocean waves arriving onshore. Large-scale flooding often occurs during seasons with exceptionally high rainfall, or springtimes that produce large snowmelt. In many places that are susceptible to annual flooding, dams and levees have been built along the waterways to prevent such flooding. Floods that result from short periods (typically several hours) of extremely heavy rain are known as flash floods and are less predictable than other floods. Flash floods occur when heavy rainfall creates local flooding as large amounts of water overwhelm creeks and rivers. One common place for flash floods is the desert. Deserts do not receive much rain, and do not absorb water quickly. When a heavy downpour occurs, streams can quickly overflow, resulting in flash floods.

Hurricanes A hurricane is a severe tropical storm, and those that hit the United States typically originate in the Caribbean Sea, the Gulf of Mexico, or the Atlantic Ocean. In other parts of the world, hurricanes are also known as tropical cyclones and typhoons. Hurricanes form in areas of warm tropical water where there is moisture and an absence of strong winds, and they can produce high winds, heavy rains, and flooding. In the United States, hurricane season runs from June through November, when water temperatures are generally higher, providing the energy for those storms.

Hurricanes, continued By definition, hurricanes have winds of at least 119 kilometers per hour (km/hr)—equal to 74 miles per hour (mi/hr)—that swirl around a calm center, known as the eye. The eye is usually about 30–50 kilometers (20–30 miles) in diameter, while the entire diameter of the hurricane may extend to 600 km (400 mi). Over the open ocean, a hurricane can last for more than two weeks. Some strike the coast of the eastern United States and then come inland, losing energy as they continue over land. The Saffir-Simpson Hurricane Scale classifies hurricanes into categories based on their wind speed (and potential to cause damage): Category One (less than 150 km/hr, or 95 mi/hr) to a Category Five (more than 250 km/hr, or 155 mi/hr).

Tornadoes A tornado is a violently rotating column of air that is in contact with both the ground and a cloud layer. It is usually seen as a funnel cloud and can have winds as strong as 500 km/hr (300 mi/hr). Tornadoes can last from several seconds to longer than an hour, though most die out in less than 10 minutes. Meteorologists use the Fujita-Pearson scale to rate the severity of tornadoes based on resulting damage and assumed wind speeds, from F-0 (less than 120 km/hr, or 73 mi/hr) to F-5 (420–510 km/hr, or 261–318 mi/hr). Tornado damage tends to occur in a narrow swath (for example, two km wide) running a long distance (up to 80 km, for example). A tornado’s high winds and low pressure (relative to normal atmospheric pressure) can cause the windows of buildings to blow outward. Compared to any other country, the United States experiences the greatest number of tornadoes. About 1,000 tornadoes are reported here per year on average, resulting in approximately 80 deaths and more than 1,500 injuries. Many of these tornadoes occur in “Tornado Alley,” a region of the central United States that includes Texas, Oklahoma, Kansas, Nebraska, and South Dakota. Tornadoes can form at any time of the year, but are most common in the United States between March and August.

Hurricanes, part 3 Hurricanes are low-pressure events. Along ocean fronts, this low pressure can create a storm surge that brings large amounts of ocean water onshore, with waves reaching up to several meters high. Storm surges cause significant damage during strong hurricanes, in part due to the large amount of water and resulting flooding. If a storm surge coincides with a low tide, the damage is lessened; but when combined with a high tide, a surge can be extremely destructive. Hurricanes are given names in alphabetical order (excluding letters Q, U, and Z) with the name of the first one each year starting with the letter A. The World Meteorological Organization rotates six lists of names and reuses names every sixth year. The name of a particularly deadly or costly hurricane, however, is retired from the lists, and a new name is selected to take its place.

Hurricane Katrina = $125 billion and 1833 fatalities, several hundred still listed as missing.