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Blowin' in the Wind, Issue #021 Summer hurricane storms - August 3, 2005
August 03, 2005
Howdy,

Hurricane storms

It's that time of year again. Time to talk about hurricane storms. Learn a few basic facts about typhoons and hurricanes.

How do cyclones form?:

Thermal lows form over land, but hurricane storms form over ocean waters. What happens if a low pressure area contains a lot of heat and moisture, and the air converges (comes together) at low levels? It must then rise. While doing so it cools, then liquid water condenses, giving off extra heat to make it more buoyant.

If this is strong enough, they give it a special name. Conditional instability of the second kind, or CISK. And it fuels the greatest storms.

Here is what we need:

1 - Warm water, at least 26C, and it has to be quite deep.

2 - Some coriolis force, at least that found at latitudes of 5 from the equator or more.

3 - Not too much wind shear. Don't want to rip the thing apart.

4 - A seed. A disturbance which grows into a hurricane.

5 - To go with the low-level convergence, the opposite must occur somewhere above at high altitudes.

With all this in place, a stream of air keeps rising like a continuous bubble. And it feeds back on itself. The lift causes condensation which provides extra heat to give more lift.

What happens?

West winds start blowing, indicating something unusual is about to take place. Over the course of the next day or so, it keeps getting more intense. We call this the formative stage which lasts until the wind reaches 63 knots or greater.

Next we have the immature stage. It lasts from the hurricane wind speed is reached until the minimum pressure and strongest winds are reached.

After this, the storm lasts for several days but usually becomes an extra-tropical cyclone, by drifting far enough from the equator. This is the mature stage. The storms usually go poleward and will encounter westerlies, which changes everything.

Now it's time for the decaying stage. There is no more warm water and the thing eventually dies.

Of course it's much more technical than this, but you can get the idea.

What to call it?

Generally, hurricane means it is in the Atlantic Ocean, and Pacific ones are known as typhoons. You can find other names for them as well.

A tropical depression only has winds less than 34 knots (about 65 km/h or 39 mph), a tropical storm has winds over 34 knots but maximum speeds less than 63 knots (125 km/h or 75 mph), and finally a hurricane/typhoon has winds greater than that.

The Saffir/Simpson scale serves as a nomenclature for hurricanes.

1. maximum winds are 64 to 83 knots (up to 95 mph or 153 km/h), storm surge 1.5 m (about 5 feet)

2. maximum winds are 44 to 95 knots (up to 110 mph or 177 km/h), storm surge 2 m or so

3. maximum winds are 96 to 112 knots (up to 130 mph or 209 km/h), storm surge 2.6 m or so

4. maximum winds are 113 to 135 knots (up to 154 mph or 248 km/h), storm surge 4 m or so

5. maximum winds are over 135 knots (go baby go), storm surge over 5.5 m (18 feet)

A storm surge is like a miniature tide under the storm. It can cause flooding.

On a first name basis - here is a list of individual names to be used on future hurricanes. Future hurricane news.

Names for hurricane storms in 2005

Arlene
Bret
Cindy
Dennis
Emily
Franklin
Gert
Harvey
Irene
Jose
Katrina
Lee
Maria
Nate
Ophelia
Philippe
Rita
Stan
Tammy
Vince
Wilma

Names for hurricane storms in 2006

Alberto
Beryl
Chris
Debby
Ernesto
Florence
Gordon
Helene
Isaac
Joyce
Kirk
Leslie
Michael
Nadine
Oscar
Patty
Rafael
Sandy
Tony
Valerie
William

Names for hurricane storms in 2007

Andrea
Barry
Chantal
Dean
Erin
Felix
Gabrielle
Humberto
Ingrid
Jerry
Karen
Lorenzo
Melissa
Noel
Olga
Pablo
Rebekah
Sebastien
Tanya
Van
Wendy

Names for hurricane storms in 2008

Arthur
Bertha
Cristobal
Dolly
Edouard
Fay
Gustav
Hanna
Ike
Josephine
Kyle
Laura
Marco
Nana
Omar
Paloma
Rene
Sally
Teddy
Vicky
Wilfred

Names for hurricane storms in 2009

Ana
Bill
Claudette
Danny
Erika
Fred
Grace
Henri
Ida
Joaquin
Kate
Larry
Mindy
Nicholas
Odette
Peter
Rose
Sam
Teresa
Victor
Wanda


Read more about hurricane names.

The most Americans killed by a Hurricane was in 1900. This storm hit Galveston, Texas with category 4 force. It took the population by surprise and flooded them with a storm surge of nearly 16 feet. Seven higher than the highest elevation there.

Hurricane Andrew cost the most. $26 billion in 1992. Hurricane Camille is also one of the most famous past hurricanes. It was the strongest since they began naming them.



A few humorous remarks

from people with hurricane experience:

An oak tree on the ground looks four times bigger than it did standing up.

When house hunting, look for closets with lots of leg room.

AA, C and D are the only alphabet we need (think batteries).

Chainsaw-wielding-men are nothing to be afraid of.

You can't spell "priceless" without I-C-E.

Gasoline is a value at any price.

Candlelight is better than botox it takes years off your appearance.

No matter how hard the wind blows, roadside campaign signs will survive.

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