Download Natural Catastrophe Notes • Tornado: a rapidly whirling, funnel

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Natural Catastrophe Notes
Tornado: a rapidly whirling, funnel-shaped cloud that reaches down from a storm
cloud to touch Earth’s surface, usually leaving a destructive path
• Most damaging have winds >250mph; Damage paths in excess of 1 mile
wide and 50 miles long
Hurricane: tropical storm with winds at least 119 mph
• Start out as tropical storms where moist, warm air above the ocean rises
and spirals upward; Winds blow in a spiral around a calm center called the
eye; Torrential rains, high winds, storm surge; May last a week or more
Flood: the overflowing of a river’s channel due to the increase of the volume of
water in the river
• Caused by thunderstorms, hurricane storm surges, melting snow and ice;
Last minutes to months; Amount of flooding is controlled by amount of
water, how porous the soil is, and the amount of water already in the soil;
Most flooding is due to humans altering the landscape
• Flooding is the most common of all natural hazards.
Wildfire: any uncontrolled fire in combustible vegetation that occurs in the
countryside or a wilderness area
• Lightning causes 1 out of 5 wildfires.; Drought, wind, high temps and low
humidity help wildfires spread.; Wind gives fire more oxygen, which dries
the fuel and pushes the fire faster.; Wildfires can produce their own winds
10X stronger than winds around them.
Drought: water shortage caused by long periods of low precipitation in an area
• Caused by an interruption of the water cycle
Volcano: an opening or rupture in the planet’s crust that allows hot magma,
volcanic ash, and gases to escape from below the surface
• Can be slow and quiet or violently explosive; New land can be created
• Hazards: hot, poisonous gases; lava flows, landslides, mudflows,
earthquakes, fire hazard, explosions, rock slides, flash flooding, and
tsunamis
• Volcanic ash can affect breathing, contaminate water, collapse roofs,
disrupt machinery, and cause jet engines to fail while flying.
Earthquake: shaking results from the movement of rock beneath Earth’s surface.
• Energy is stored as stress builds in Earth’s plates.
• When the rocks move, the stored energy is released as kinetic energy.
• Can be caused by a volcanic eruption or plate collisions
• Can open large cracks in the ground, causing bodies of water to disappear
Tsunami: series of water waves caused by the displacement of a large amount of
water, usually after an earthquake or volcanic eruption
• Can also be caused by meteorite impact or underwater landslides
• Waves 450-600 mph; Get slower and taller as the wave approaches coast
• Often come ashore as a rapidly rising turbulent surge of debris filled water
• Areas of risk are less than 25 ft above sea level and within 1 mile of shore