Name: ______________________ Date: ________ Class Period



HURRICANE ANDREW TRACKING INVESTIGATION

Objectives:

• Plot latitude and longitude coordinates on a map.

• Compare and contrast weather advisories such as “hurricane watch” and “hurricane warning.”

• Give examples of actions to take to prepare for a hurricane.

• Describe the conditions necessary for a hurricane to develop and how it dies out.

Introduction:

Like other Atlantic hurricanes, Andrew started as a low-pressure system in the tropics off the west coast of Africa. Warm water and moisture-laden air supplied the energy for it to strengthen into an ordinary and average tropical storm. Surface winds began to move the storm westward.

Although all tropical storms form and develop in this way, only a few intensify into hurricane. Most encounter upper air winds moving in the opposite direction as the surface winds. As a result, these storms weaken and soon die out. Tropical Storm Andrew, on the other hand, encountered upper air winds moving in the same direction as the surface winds. These reinforcing winds caused Andrew to quickly strengthen into an unusually powerful hurricane. Andrew proved to be one of the most intense Atlantic hurricanes of the 20th century.

History and Basics:

Weather satellites collect latitude and longitude coordinates to allow people to plot the paths of hurricanes and make predictions and advisories as to where they will make landfall. The National Hurricane Center tracks the hurricanes and issues their best estimate as to when and where a hurricane will hit and possible intensity levels.

• A tropical depression is an organized system of clouds and thunderstorms with a defined surface circulation and maximum sustained winds of 38 miles per hour.

• A tropical storm has maximum sustained winds of 39-73 mph.

• A hurricane has a well-defined surface circulation with sustained winds of 74 mph or greater and are categorized by their winds speeds. Category 1 is the weakest and Category 5 is the strongest.

If a hurricane is predicted to make landfall within 24-36 hours, the area affected is put under a hurricane watch. If a hurricane is predicted to make landfall in less than 24 hours, that area is put under a hurricane warning.

The deadliest part of a hurricane is the storm surge - a wall of ocean water pushed by the winds of a hurricane. This storm surge can come ashore up to 12 hours prior to landfall and can raise the sea level up to 25 feet.

The calm “eye” of the hurricane can be up to 40 miles wide and often fools people into believing the storm is over resulting in injuries and fatalities. The eye wall winds around the eye have the most severe winds.

The death of a hurricane results from the loss of moisture and warm water. Upon landfall (or crossing an island), hurricanes begin to die out due to a lack of the moist, warm water which helps to intensify them. Higher latitude (cooler waters) can also cause a hurricane to dissipate.

Prior to 1953, hurricanes were named by where they hit or their coordinates. In 1953, hurricanes began having female names to help identify them in tropical waters, especially when there were multiple storms occurring simultaneously. It wasn’t until 1979 that the hurricanes began alternating between male and female names in alphabetical order in a six-year rotating list. These names are used repeatedly unless they are retired due to substantial damage or death.

Throughout Virginia’s history, over 69 eyes of cyclones have passed over the state and 11 have made landfall within 60 miles of Virginia’s coasts.

PROCEDURES: PLEASE READ AND FOLLOW THE INSTRUCTIONS CAREFULLY.

1. Using the Wind speeds on the Data Table and the Saffir/Simpson Scale below, determine the status of the storm either a Tropical Storm or a Hurricane + Category. Fill in this information in the last column of the Data Table. (Two examples are done for you.)

PART I: Tracking the Storm – Latitude and Longitude

2. Using the Hurricane Andrew Data Table, plot the track of Hurricane Andrew on the Map by marking a point at the correct latitude and longitude given.

3. Label each point you have plotted with the date and the time. Notice the times are on a 24-hour clock.

Example: the 1st lat/long point for August 21, 03:00 hrs, should be labeled “21/03.” August 21, 09:00 hrs = “21/09.”

4. Develop a colored coded key to represent the status of the storm. You will use five different colors. Create a key in the margin of the map. Example: Blue = Tropical Storm, Green = Category 1 Hurricane, and so on. Connect the lat/long points on your map with a colored pencil showing the storms track.

PART II: Graphing the Wind Speed & Graphing the Air Pressure

❖ You will plot two different sets of data on the same graph!

5. Use a colored pencil or a marker to plot the data for Hurricane Andrew’s WIND SPEED vs. TIME on the Graph. Connect the points with a smooth curve.

6. Use a different colored pencil or marker to plot the data for the hurricane’s AIR PRESSURE vs. TIME on the same graph. (The scale for air pressure is on the other side across from wind speed.) Connect the points with a smooth curve.

Part III: Landfall Times

7. Look at the map where you plotted the track of the Hurricane. Circle the points where the Hurricane touches land.

Part IV: Answer the Analysis and Conclusion Questions

Hurricane Andrew Tracking Investigation

|HURRICANE ANDREW DATA TABLE |

|DATE |TIME |LATITUDE |LONGITUDE |PRESSURE |WIND SPEED |STATUS |

| |09:00 hrs |24.3o N |63.7o W |1006 mb |60 mph | |

| |15:00 hrs |24.7o N |64.6o W |1007 mb |60 mph | |

| |21:00 hrs |25.2o N |65.4o W |1004 mb |60 mph | |

|Aug 22 |03:00 hrs |25.6o N |66.5o W |1001 mb |63 mph | |

| |09:00 hrs |25.8o N |67.5o W |994 mb |75 mph |Hurricane - 1 |

| |15:00 hrs |25.9o N |69.0o W |974 mb |92 mph | |

| |21:00 hrs |25.9o N |70.4o W |974 mb |98 mph | |

|Aug 23 |03:00 hrs |25.6o N |71.9o W |959 mb |109 mph | |

| |09:00 hrs |25.5o N |73.4o W |951 mb |119 mph | |

| |15:00 hrs |25.4o N |75.0o W |930 mb |134 mph | |

| |21:00 hrs |25.4o N |76.5o W |923 mb |150 mph | |

|Aug 24 |03:00 hrs |25.4o N |78.1o W |931 mb |140 mph | |

| |09:00 hrs |25.4o N |80.3o W |932 mb |140 mph | |

| |15:00 hrs |25.7o N |82.1o W |945 mb |140 mph | |

| |21:00 hrs |25.8o N |83.9o W |945 mb |140 mph | |

|Aug 25 |03:00 hrs |26.3o N |85.7o W |945 mb |140 mph | |

| |09:00 hrs |26.8o N |87.0o W |949 mb |140 mph | |

| |15:00 hrs |27.5o N |89.2o W |944 mb |140 mph | |

| |21:00 hrs |28.2o N |90.2o W |937 mb |140 mph | |

|Aug 26 |03:00 hrs |29.0o N |91.1o W |940 mb |140 mph | |

| |09:00 hrs |29.7o N |91.7o W |954 mb |115 mph | |

| |15:00 hrs |30.5o N |91.6o W |987 mb |75 mph | |

| |21:00 hrs |30.6o N |91.6o W |991 mb |50 mph | |

Name: _________________________________________ Date: ________________________ Block: ______

Analysis and Conclusions

1. What is the difference between the highest and the lowest air pressure values given in the data table?

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2. Would you expect the value above to be more or less than the air pressure change across a typical low pressure system? Explain.

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3. Between August 24, 15:00 and August 26, 3:00, the wind speed for Hurricane Andrew remained essentially the same. Where was Hurricane Andrew located during this period of time?

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4. According to your graph, what is the general relationship between air pressure and wind speed?

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5. How did Hurricane Andrew’s air pressure and wind speed change after both of the hurricane’s landfalls?

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6. How did Hurricane Andrew’s air pressure and wind speed change after the hurricane left the west coast of Florida and moved over water?

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7. Explain why you think air pressure and wind speed are affected by the surface over which a hurricane moves.

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8. Compare the length of the hurricane track between the points plotted for Aug 24, 15:00 and Aug 25, 15:00, to the length of the track between Aug 25, 15:00 and Aug 26, 15:00. During which twelve-hour time period did the hurricane move faster?

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9. Why did the hurricane’s speed change?______________________________________________________

10. a) A tropical storm officially becomes a hurricane when it attains speeds greater than 74 mph. What day did Hurricane Andrew change from a tropical storm to a hurricane?

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10. b) What day did it change back to a tropical storm? ____________________________________________

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SAFFIR/SIMPSON SCALE

The Relationship between Wind Speed and Air Pressure over Time.

Date & Time

30° N

20° N

25° N

80° W

75° W

85° W

90° W

95° W

65° W

70° W

60° W

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