Hurricanes What Is A Hurricane Hurricanes are intense

Hurricanes

What Is A Hurricane? • Hurricanes are intense tropical cyclones with a maximum sustained speed of at least 65 knots (74 mph).

By Any Other Name • Hurricanes form in the warm waters of the world. • In the Eastern Pacific they are called typhoons. • In the Indian Ocean they’re called cyclones.

By Any Other Name • They usually form from some old low pressure system or tropical wave. • If the wave develops circulation and reaches winds of 35 knots( 39 mph ) they are tropical storms and named.

Physical Make-up • Hurricanes have a diameter of less than 100 miles to over 500 miles.

Physical Make-up • They have a more or less circular “eye” which may be well defined in stronger storms.

Hurricane Power • Hurricanes are ranked on a 1 -5 scale called the Saffir. Simpson Scale.

Hurricane Power • A 1 would be a minimal hurricane with winds 74 -95 mph. • A 5 is catastrophic with winds 155 mph+

Saffir Simpson Scale Category Pressure (mb) Wind speed (mph) Damage 74 -95 Storm surge (ft) 4 -5 1 >980 2 965 -979 96 -110 6 -8 Moderate 3 945 -964 111 -130 9 -12 Extensive 4 920 -944 131 -155 13 -18 Extreme 5 <920 >155 >18 ft Catastrophic Minimal

CAT 1 Damage

CAT 2 Damage

CAT 3 Damage

CAT 4 Damage

CAT 5 Damage

Danger from Hurricanes • In the US, most people that die from hurricanes are killed by fresh water flooding.

Danger from Hurricanes • Worldwide, most die from the storm surge. • Why would that occur?

Storm Surge • To Answer that question let’s take a look at storm surge.

Think You Know Why? In the US our warning system is so good that people along the coast know when the storm is coming.

Think You Know Why? In many parts of the world people may not know to leave.

Think Back! • Fresh water flooding was the number one cause of death in the United States.

• Do you remember from the graph the number two cause of death by hurricane in the U. S. ?

THE WIND! • Take a look at this piece of wood that was driven into the palm tree.

THE WIND! • Flying objects in the wind can be very dangerous.

Here A Few Hurricane Questions! • When is the official starting date for the Atlantic Hurricane season?

Here A Few Hurricane Questions! • What is the last day of the hurricane season?

THE ANSWER! • The Atlantic Season begins June 1 st and ends on November 30 th. • BUT! Atlantic hurricanes have occurred in every month but one!

During Which Month Do We Have The Largest Number Of Hurricanes? • On the average, there are 10 named storms a year. Historically, September is the month with the most named storms.

Hurricanes That Have Impacted Our Area.

The Great Atlantic Hurricane of 1944 • This storm had reported sustained winds of 134 mph at the mouth of the Chesapeake Bay

Hurricane Hazel in 1954 • Hurricane Hazel caused a great deal of damage to the Tidewater area with sustained winds in excess of 100 mph.

Hurricane Camille in 1969 • One of the Few Category 5 storms to hit the US. • 113 died in Virginia due to the heavy rains and flash floods. • Richmond was flooded!

Hurricane Floyd in 1999 • Hurricane Floyd caused a great deal of flooding and power outages from fallen trees. • Notice the rain bands.

Bonus Question! • What Two Things Will Kill Or Weaken A Hurricane? • Think About The Things That Are Needed For A Hurricane To Form.

The Answer! • Cold Water AND Land!

Now A Quick Review! • A hurricane must have a sustained wind of at least ___ mph. • 74

#2 • Hurricanes are called _______ in the Eastern Pacific. • Typhoons

#3 • What is the name of the hurricane intensity scale? • Saffer-Simpson

#4 • What aspect about hurricanes kills the most people in the U. S. ? • Freshwater Flooding

#5 • When does the Atlantic Hurricane season officially begin? • June 1 st

The Last Question! • What Category 5 hurricane killed over 100 people in Virginia? • Camille