Hurricanes. Cause: a low pressure storm system over warm ocean water. Effect: potential massive widespread destruction and flooding.

Transcription

1 Hurricanes

2 Hurricanes Cause: a low pressure storm system over warm ocean water. Effect: potential massive widespread destruction and flooding.

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4 Hurricanes also known as: cyclone (Indian Ocean) or typhoon (Pacific Ocean) Similar to a low pressure system over land but it is over water form in warm Atlantic regions where water is at least 27 degrees Celsius (80 degrees Fahrenheit), and moist air with converging winds. Most Atlantic hurricanes begin off the west coast of Africa, starting as thunderstorms that move out over the warm, tropical ocean waters.

5 Stage 1: a tropical depression an organized system of clouds and thunderstorms with a defined surface circulation and maximum sustained winds of less than 17 m/s (38 mph) Hurricanes

6 Stage 2: a tropical storm an organized system of strong thunderstorms with a defined surface circulation and maximum sustained winds between 17 and 32 m/s (39 73 mph) distinctive cyclonic shape starts to develop, though an eye is usually not present Hurricanes

7 Stage 3: a hurricane a system with sustained winds greater than 33 m/s (74 mph), has an eye, an area of relative calm at the center of circulation surrounding the eye is the eyewall, an area about mi (16 80 km) where the strongest thunderstorms and winds circulate Hurricanes

8 Hurricanes Category Winds Effects One Two Three Four Five mph mph mph mph greater than 155 mph No real damage to building structures. Damage primarily to unanchored mobile homes, shrubbery, and trees. Also, some coastal road flooding and minor pier damage Some roofing material, door, and window damage to buildings. Considerable damage to vegetation, mobile homes, and piers. Coastal and low-lying escape routes flood 2-4 hours before arrival of center. Some structural damage to small residences and utility buildings with a minor amount of wall failures. Mobile homes are destroyed. Flooding near the coast destroys smaller structures with larger structures damaged by floating debris. More extensive curtain wall failures with some complete roof structure failure on small residences. Major erosion of beach. Major damage to lower floors of structures near the shore. Terrain continuously lower than 10 feet above sea level may be flooded requiring massive evacuation of residential areas inland as far as 6 miles. Complete roof failure on many residences and industrial buildings. Some complete building failures with small utility buildings blown over or away. Major damage to lower floors of all structures located less than 15 feet above sea level and within 500 yards of the shoreline. Massive evacuation of residential areas on low ground within 5 to 10 miles of the shoreline may be required.

9 Hurricane Safety Hurricane watch = hurricane possible within the next 36 hours, be prepared to evacuate Hurricane warning = hurricane expected within 24 hours, evacuate now If hurricane is coming, leave to be safe. Much of the danger is from flooding

10 Naming of Hurricanes The World Meteorological Organization uses six lists in rotation. The same lists are reused every six years. The only time a new name is added is if a hurricane is very deadly or costly. Then the name is retired and a new name is chosen (such as Katrina). Hurricane Names

11 Notable Hurricanes The Bhola cyclone is the deadliest on record, killing over 300,000 and potentially as many as 1 million after striking the densely populated Ganges Delta region of Bangladesh on November 13, Hurricane Katrina is estimated as the costliest worldwide, causing $81.2 billion in property damage with overall damage estimates exceeding $100 billion. Katrina killed at least 1,836 people after striking Louisiana and Mississippi in August The Galveston Hurricane of 1900 is the deadliest natural disaster in the United States, killing an estimated 6,000 to 12,000 people in Galveston, Texas. Hurricane Iniki in 1992 was the most powerful storm to strike Hawaii in recorded history, hitting Kauai as a Category 4 hurricane, killing six people, and causing U.S. $3 billion in damage.

12 Notable Hurricanes In addition to being the most intense tropical cyclone on record, Tip was the largest cyclone on record, with tropical storm-force winds 1,350 miles in diameter. The smallest storm on record, Cyclone Tracy, was roughly 60 miles wide before striking Darwin, Australia in 1974.

13 Quick Clicker Quiz

14 1. What is the cause of a hurricane? A. A high pressure system over the ocean. B. A low pressure system over the ocean. C. A high pressure system over land. D. A low pressure system over land.

15 2. What is the correct order of hurricane stages? A. tropical depression, hurricane, tropical storm B. Hurricane, tropical depression, tropical storm C. tropical depression, tropical storm, hurricane D. tropical storm, tropical depression, hurricane

16 3. What scale do we measure hurricanes with? A. Height in miles B. Category (1-5) C. Enhanced Fujita Scale (EF0 EF5) D. ph scale (1-14)

17 4. What does a Hurricane warning mean? A. Hurricane is possible, prepare to evacuate B. Hurricane is expected, evacuate now C. Hurricane has landed, take shelter D. Hurricane has passed, it is safe

18 Drought

19 Drought Cause: drought occurs when more water is taken out of a reservoir than is added to it. Result of persisting clear skies with little or no precipitation, and excessive use of water for human activities. Effect: decreased crop production, decreased drinking water quality and availability, and food shortages. As population increases the demand for food and water increases, and probability of a drought increases and the dangers of drought become more and more serious. Also, when vegetation becomes dry during a drought, fire risk increases, threatening homes, crops, and lives

20 Drought

21 Impact on River Navigation

22 Impact on Crops Two ears of corn from different parts of the field. One is stunted by dry weather, the other is close to normal.

23 Impact on Tourism Elbe River Germany

24 Drought Can (and has) lead to dangerous events: 1930 s - 3 waves of drought during this time are referred to as "the Dust Bowl (was a contributing factor to the Great Depression wildfires dry vegetation can catch flame very easily during a period of drought

25 Drought

26 Quick Clicker Quiz

27 5. What is the cause of a drought? A. When more water is taken out of a reservoir than is added to it. B. When more water is added to a reservoir than is taken out. C. When water is used by crops instead of for drinking. D. When there is no precipitation for 2 months straight.

28 6. Which is not an effect of drought? A. Decreased crop production B. Decreased drinking water quality and availability C. Food shortages D. Decreased risk of wildfire

29 7. Where is the drought likely to get worse? A. B. C. D.

30 8. During a drought, drinking water quality decreases. A. True B. False