HURRICANES Source: http://www.dc.peachnet.edu/~pgore/students/w97/matheson/hpage.htm
What is a hurricane? Violent cyclonic storm that develops in the tropical region Wind speeds are > 74 mph Source: http://www.google.com/imgres?hl=en&sa=x&biw=1920&bih=955&tbm= isch&prmd=imvnsu&tbnid=g5lfa0z0v32sem:&imgrefurl=http://wattsupwiththat.com
Rotation and Pressure In which direction does a hurricane rotate? COUNTERCLOCKWISE In Northern Hemisphere CLOCKWISE In Southern Hemisphere Is the barometric pressure inside the hurricane high or low? LOW
When is Hurricane Season? June 1 st through November 31st
National Weather Service Provides weather information, such as data from satellites Responsible for issuing watches and warnings to the media and general public
Watch vs. Warning Watch Tropical storm poses a threat to coastal areas with 36 hours Warning - Tropical storm conditions are expected in a coastal area within 24 hours
Surface Pressure lowest in eye and wind speeds highest in eye-wall
Where are these Hurricanes forming? Intertropical Convergence Zone The ITCZ is an area of low pressure located roughly 5 degrees North and South of the Equator It is a place where air converges, rises, and condenses (forming clouds). It is the rainiest place on Earth!
What Does a Hurricane Need in Order to Develop? A hurricane needs warm water, time to grow, and favorable upper level winds in the troposphere. If the winds are too strong, they will blow the hurricane apart we call that wind shear!
Evolution of Hurricane Development -- Stages Stage 1 Tropical Wave (Depression) Usually has begun its life off of the west coast of Africa in the ITCZ. Tropical depressions have winds of less than 39mph, and are not given a name. Lacks structure no well developed feeder bands or eye
Stage 2 Tropical Storm At this point, the tropical storm is beginning to develop some serious structure. Winds range from 40-73 mph. In the Atlantic, storms are given a name when they reach this stage. Feeder bands are beginning to develop you can see the center of the low pressure system more easily. Eye and eye wall still not well formed.
Stage 3 Category 1 Hurricane Winds range from 75-94 mph. Well developed feeder bands. An eye begins to form. Storm is tightening around center.
Stage 4 Category 2 Hurricane Winds range from 95-110 mph. Well developed feeder bands. An eye and eye wall are usually very well formed. Storm continues to tighten around center.
Stage 5 Category 3 Hurricane Winds range from 111-130 mph. Now considered a Major Storm. Intense flooding and building damage will occur to most areas on the coast. Further inland, the damage will still be substantial.
Stage 6 Category 4 Hurricane Winds range from 131-155 mph. All shrubs, signs and trees blown down. Extensive damage to doors and windows. Major damage to lower floors of structures near the coast.
Stage 7 Category 5 Hurricane Winds greater than 156 mph! Complete roof failure on many residential and industrial buildings. Some complete building failures with small utility buildings away. Massive evacuation of residential areas on low ground (5-10 miles)
How do they measure hurricanes strength? Saffir-Simpson Hurricane Scale Category Wind speed (mph) Storm surge (feet) 5 156 More than18 4 131 155 13 18 3 111 130 9 12 2 96 110 6 8 1 74 95 4 5 Additional classifications Tropical storm 39 73 0 3 Tropical depression 0 38 0
Most Hurricanes are Category 1-3 on the Saffir-Simpson scale. Few are 4 & 5. 1900-2007 climatology.
What destroys a hurricane? Strong vertical winds Cold water Movement over land Friction Lack of moisture
What are the five costliest hurricanes in the United States? Rank: Name: Year: Category: Damage (U.S.): 1. Katrina 2005 3 $105,840,000,000 2. Andrew 1992 5 $45,561,000,000 3. Ike 2008 2 $27,790,000,000 4. Wilma 2005 3 $20,587,000,000 5. Ivan 2004 3 $19,832,000,000
Explain why the majority of the costliest storms are relatively recent Damage is a result of development There are more developed areas and possessions than in the past Source: http://www.nhc.noaa.gov/1992andrew.html