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EARTH SCIENCE

HURRICANE STRIKE!

Created by Dawn Sherwood

Highland Springs H.S., Henrico, VA

For teachers:  there are also worksheets on this page that you can use with the entire activity.

http://meted.ucar.edu/hurrican/strike/misc/info_3.htm#worksheets

Go to http://meted.ucar.edu/hurrican/strike/orig/htcmenu.htm

Click on neighborhoods and read each link.

Tropics

What is a tropical cyclone and what direction do they spin in each hemisphere?

Storms born in the tropics and spin cyclonically.  This means clockwise in the Southern Hemisphere and counterclockwise in the Northern hemisphere.

Names and places

What do you call a tropical cyclone (3 different names) and where are they each located?

Atlantic/E. Pacific       weak-Tropical Storm             strong-Hurricane

NW Pacific                 weak-Tropical Strong                        strong-Typhoon

SW Pacific/Indian       Cyclone

Evil Wind

What is the origin of the word Hurricane?

Mayan God Huracan

Click on Seasons and read each link

Hurricane Season

In the Atlantic Basic, what are the dates of hurricane season?

June 1 – end of November

Typhoon and Cyclone Season

Which area has the most tropical cyclones?

Northwest Pacific Ocean

Click on Lifecycles

Birth

Nearly all tropical storms/hurricanes begin as tropical disturbance.  Sometimes, they grown into tropical wave that blows across the Atlantic from Africa.

What 5 ingredients are needed for a tropical disturbance to become a tropical cyclone and then a tropical storm/hurricane?

1.  Tropical disturbance with thunderstorms

2.  Distance at least 500 km (300 m) from equator

3.  Ocean temperature at least 80°F or warmer to depth of at least 164’

4.  Lots of moisture in lower and middle parts of atmosphere

5.  Low wind sheer

Growth

Complete the table below

Evil Eye

What is the eye of a hurricane?

As the storms gets stronger, it gets rounder and the eye forms.  The most intense winds form in the eyewall area.

Rotation

Which way does a tropical cyclone rotate in the northern hemisphere?

Counter-clockwise

Which way does a tropical cyclone rotate in the southern hemisphere?

Clockwise

Demise

What are the three things that can cause a hurricane to die?

Move over cool water or land or come in contact with strong upper level wind

How strong are breeze, gale, and hurricane-force winds?  Breeze = 4-31 mph; Gale=32-63 mph; Hurricane=74+ mph

What are the categories of hurricanes? 1-5

Click on Categories

Beaufort Scale

What is the Beaufort Scale?

Winds below hurricane force winds.  0-12 category

What are the signs of #8 Fresh Gale?

Twigs break off of trees

Saffir-Simpson Scale

What is the Saffir-Sampson Scale?

Describes hurricane force winds.  Has a scale of 1-5

Complete the following chart

How much more damage does a Category 5 cause than a Category 1?

a) 5 times         b) 10 times       c)50 times        d) 500 times

How much damage does each category of hurricane produce?

Category 1 – minimal damage

Category 2 -  moderate damage

Category 3 -  extensive damage

Category 4 –  extreme damage

Category 5 –  catastrophic

Click on Journeys

What are the three main factors that move a tropical cyclone?

Wind belts, highs, and lows

Wind Belts

What are the 2 sets of winds belts and where are they located?

Tropical Easterlies (E to W) on each side of equator

Mid-latitude Westerlies (W to E) halfway between equator and poles

Highs and Lows

Circulation around a High Pressure System is:  Clockwise

Circulation around a Low Pressure System is:   Counterclockwise

Hurricane A will probably go toward NorthEast

Hurricane B will probably go toward West

Paths of Destruction

Tropical cyclones usually start out moving toward the West

Tropical cyclones that cross the Tropic of Cancer usually move toward the Northwest, North, Northeast

Tropical cyclones never cross the equator

http://meted.ucar.edu/hurrican/strike/orig/canelab.htm

In order to form a hurricane, you need:  wind direction and speed to be same

What is the direction and strength of your winds

What is the moisture in the atmospheric layers

What is the most favorable range of latitude for Atlantic Hurricane formation?

5-30 °N

What is the minimum sea temperature °C for the growth of a hurricane?  Above 25°C

True/False     To form, hurricanes need a lot of wind sheer and very little moisture.

http://meted.ucar.edu/hurrican/strike/orig/anatomy.htm

Read each part of a hurricane and complete

Inside the Storm

Inflow

1. Air rising, forming thrunderstorm
2. Warm humid air flow inward, speeding up as it approaches the eyewall
3. Winds spiral in eyewall

Rainbands

            Typically 3-30 miles wide and up to 300 miles long.

Eyewall

1. Eye:  light winds, partly cloudy or clear sky, average diameter 20-50 km.
2. Eyewall:  heaviest ppt and strongest winds
3. spiral winds in eyewall

4.   sinking air

Outflow

1. Air flow flowing out from center of storm
2. Air sinking into storm’s center, warming and suppressing clouds.  Winds calm
3. Cirrostratus clouds capping storm

http://meted.ucar.edu/hurrican/strike/orig/movncane.htm

Click and drag the blue low (L) onto a low target over the US, the red high (H) onto a high target over the Atlantic Ocean, and a hurricane onto either starting location target over the Atlantic.

TEACHERS:  these answers are not the ONLY way.  Type in their positions to check their answers (I would recommend keeping track of their correct answers.

In order for hurricane to strike NC/VA area, where can the L, H, and hurricane be?

L:  Pensacola                          H:  Miami        Hurricane:  lower position

In order for hurricane to strike between New Orleans and Pensacola, where can the L, H, and hurricane be?

L:  Houston                 H:  Miami                    Hurricane: lower position

In order for hurricane to strike New Orleans area, where can the L, H, and hurricane be?

L:  Midwest                             Miami

H:  Houston                             Virginia

Hurricane:  lower position

In order for hurricane to strike Houston area, where can the L, H, and hurricane be?

L:  Midwest                 H:  Virginia                 Hurricane:  lower position

What do you notice that high and low pressure systems do to guide a hurricane?  Create a path that they follow

Tracking Hurricane Erin

If you do not already have a tracking chart, you can print one out from this site:

http://meted.ucar.edu/hurrican/strike/key/track.pdf

Complete the following questions using the appropriate chart.

http://meted.ucar.edu/hurrican/strike/orig/stotrk_1.htm

What is a track chart?  Shows location and path of a tropical cyclone’s center

What do the various colors represent?  Green – tropical storm; red – hurricane; yellow dots – 8 p.m. location; blue – 8 a.m. location

What are watches and warning for Tropical Storms and Hurricanes?  Tropical Storm Watches – tropical storm may threaten within 36 hours; Tropical Storm Warning – threaten within 24 hours; Hurricane Watch – hurricane may threaten in 36 hours; Hurricane Warning – threaten within 24 hours or less

On a tracking chart, please track Hurricane Erin Sunday, July 30 through Friday, August 4^th.  Use the colors indicated in the map for each day.

http://meted.ucar.edu/hurrican/strike/orig/stotrk_2.htm

In visible light imagery, clouds are white, and land/water are gray or black.

It “sees” sunlight reflected from Earth and clouds, so it can only be used during the day..

What is Infrared Satellite Imagery?  Earth surface absorbs half of energy that comes from sun.  Air and clouds absorbs a little.  Ground, clouds, and air re-emit light as heat.

When can IR Satellite Imagery be used?  Day and night

How is IR Satellite Imagery used?  Used to estimate how high cloud tops are above the ground.  Tall clouds with really cold tops are often created by strong thunderstorms.

What are written advisories?  NWS writes and broadcasts advisories for ppl who may be affected by tropical storms or hurricanes

Continue tracking the hurricane on the chart

http://meted.ucar.edu/hurrican/strike/orig/stotrk_3.htm

Continue tracking the hurricane on the chart

http://meted.ucar.edu/hurrican/strike/orig/stotrk_4.htm

What is Radar Imagery?  Senses clouds and moisture in air.  Sends out pulses of energy and listen to pattern of reflected energy.  Creates picture showing location of clouds/moisture.

What do the different colors represent?  Blue/green – rain light; yellow/orange/red – heavy rains

Continue tracking the hurricane on the chart

Look at the radar

http://meted.ucar.edu/hurrican/strike/orig/stotrk_5.htm

Continue tracking the hurricane on the chart

Look at the radar

http://meted.ucar.edu/hurrican/strike/orig/stotrk_6.htm

Continue tracking the hurricane on the chart