Ch. 11: Hurricanes. Be able to. Define what hurricane is. Identify the life and death of a hurricane. Identify the ways we track hurricanes.

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2 Ch. 11: Hurricanes Be able to Define what hurricane is. Identify the life and death of a hurricane. Identify the ways we track hurricanes.

3 What are Hurricanes? Smaller than mid-latitude cyclones. Don t have warm and cold fronts. Most destructive storms on earth.

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5 What/ Where are Hurricanes? A hurricane is an intense tropical low-pressure area with sustained winds of 74mph or greater. They circulate counterclockwise about their centers in the Northern Hemisphere. Most Hurricanes form between the latitudes of 5 and 20

6 Who s # 1 North Pacific has the greatest number of storms. average 20 per year U.S. Only averages 11 tropical storms, and 6 hurricanes in the Atlantic Ocean.

7 Hurricane Data 4 methods of gathering data on hurricanes 1. Satellite Best Method 2. Reconnaissance aircraft 3. Radar 4. Data buoys

8 Hurricane Destruction Hurricanes cause damage three ways: 1. Strong winds 2. Heavy rains 3. Storm Surge

9 The greatest damage associated with hurricanes is caused by? Storm surges

10 Storm Tide Facts Hurricane Camille in 1969 produced a 24-foot storm tide in Mississippi. Hurricane Hugo in 1989 generated a 20-foot storm tide in South Carolina. Hurricane Katrina in 2005 generated a 27-foot storm tide in Mississippi.

11 Hurricane Season

12 Hurricane Season North American hurricane season is normally from June to November. The most active months in the Atlantic are: Aug. Oct.

13 The three Category 5 storms to hit the USA: Florida Keys "Labor Day" hurricane. 2. Hurricane Camille, which hit Mississippi in Hurricane Andrew, which hit Florida, on Aug. 24, 1992.

14 Birth of a Hurricane Hurricanes are formed from complex of thunderstorms. The ocean water itself must be warmer than 80 F. The heat and moisture from this warm water is ultimately the source of energy for hurricanes.

15 Death of a Hurricane Hurricanes will weaken rapidly when they: travel over land travel over colder ocean waters locations with insufficient heat and/or moisture.

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17 Wind Shear Wind shear is defined as the amount of change in the wind's direction or speed with increasing altitude. Weak wind shear is good for tropical storm development. Strong wind shear is bad for tropical storm development.

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19 Hurricane Life Cycle 1) Tropical Disturbance or Wave Most common, about 100 forming each season. They lack a closed circulation Wind speeds are less than 20 knots, or 25 mph.

20 Hurricane Life Cycle 2) Tropical Depression A wave becomes a depression when there is a presence of a closed circulation, and sustained winds are 20 knots, or 25 mph. At this point, the system is still quite disorganized.

21 Hurricane Life Cycle 3) Tropical Storm A depression becomes a tropical storm when thunderstorm activity moves over the closed circulation, and sustained winds reach at least 35 knots, or 39 mph. At this point, the system is capable of causing minimal damage, and the storm receives a name. Example. - T.S. Katrina)

22 4) Hurricane Hurricane Life Cycle A tropical storm becomes a hurricane when the closed circulation becomes an eye, and sustained winds reach at least 65 knots, or 74 mph. At this point, the system is capable of causing significant damage. * Sustained winds A 1-minute average wind measured at about 33 ft (10 meters) above the surface.

23 Life Cycle of a Hurricane

24 Other Names for Hurricanes Hurricane is given to systems that develop over the Atlantic or the eastern Pacific Oceans. Typhoons in the western North Pacific and Philippines Cyclones in the Indian and South Pacific Ocean

25 Saffir-Simpson Hurricane Scale A Category 1 storm has the lowest wind speeds, while a Category 5 hurricane has the strongest. The maximum sustained surface wind speed (peak 1- minute wind at 33 feet/10 meters) is the determining factor in the scale.

26 The Worst U.S Hurricanes Most Damage Hurricane Katrina, August 2005, was the costliest hurricane in history, racking up more than $80 billion in damages. (#2 Hurricane Andrew, $ 26 billion) Deadliest Galveston Hurricane 1900, 8,000 deaths attributed to the storm. Strongest Hurricane Camille, which hit Mississippi with winds at 190 mph in The 882 mb pressure reported in Hurricane Wilma in 2005 is the lowest central pressure on record in an Atlantic hurricane

27 Hurricane Watch vs. Warning HURRICANE WATCH: Hurricane conditions are possible. The hurricane watch is issued 48 hours in advance of the anticipated onset of tropical-storm-force winds. HURRICANE WARNING: Hurricane conditions are expected. The hurricane warning is issued 36 hours in advance of the anticipated onset of tropicalstorm-force winds.