Hurricane Andrew Tracking Investigation
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 the most intense
Atlantic hurricane 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, while 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.
.
Materials:
 Sharpened Pencil, Colored Pencils, Atlantic Hurricane Tracking Map, Hurricane Data, Analysis
Questions
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.
Procedures: Please read and follow the instructions carefully.
PART I: Tracking the Storm – Latitude and Longitude
1. Using the Wind speeds on the Data Table and the Saffir/Simpson Scale, determine the status of the
storm (T.S. or Hurricane & Category). Fill in this information in the last column of the Data Table.
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. * Start with the data from August 21, 03:00 hours.* Notice the
times are on a 24-hour clock.
3. Label each point you have plotted with the date and the time.
Example: the 1st data point for August 21, 03:00 hrs, should be labeled “21/03.”
the next data point for August 21, 09:00 hrs, should be labeled “21/09.”
4. Connect the points with a colored pencil showing the storms track. Develop a colored coded key to
represent the status of the storm. For example: Blue = Tropical Storm, Green = Category 1 Hurricane, and so
on. You will use five different colors.
PART II: Graphing the Wind Speed
5. Use a colored pencil or a marker to plot the data for Hurricane Andrew’s wind speed vs. time on the Graph
(located after the analysis questions). **Begin with the data on August 21. **
6. Connect the points with a smooth curve.
PART III: Graphing the Air Pressure
7. Use a different colored pencil or marker to plot the data for the hurricane’s air pressure vs. time (on the
same Graph as the wind speed.) **Begin with the data on August 21. **
8. Connect the points with a smooth curve.
Part IV: Landfall Times
9. Look at the map where you plotted the track of the Hurricane. Circle the points where the Hurricane
touches land. Note the date and time.
10. In a 3rd colored pencil/marker and a ruler, draw a vertical line on the Wind Speed/Air Pressure Map
through the date & time of the landfall times (the points you circled.)
11. Answer the Analysis and Conclusion Questions
SAFFIR/SIMPSON
SCALE
Hurricane Andrew Tracking Investigation
Name ______________________
Period _____ Date ______
Earth Science
Hurricane Andrew Data Table
Date
Aug 21
Aug 22
Aug 23
Aug 24
Aug 25
Aug 26
Time
(24-hour
clock)
03:00
09:00
15:00
21:00
03:00
09:00
15:00
21:00
03:00
09:00
15:00
21:00
03:00
09:00
15:00
21:00
03:00
09:00
15:00
21:00
03:00
09:00
15:00
21:00
Latitude
( oN )
Longitude
( oW )
23.7
24.3
24.7
25.2
25.6
25.8
25.9
25.9
25.6
25.5
25.4
25.4
25.4
25.4
25.7
25.8
26.3
26.8
27.5
28.2
29.0
29.7
30.5
30.6
63.0
63.7
64.6
65.4
66.5
67.5
69.0
70.4
71.9
73.4
75.0
76.5
78.1
80.3
82.1
83.9
85.7
87.0
89.2
90.2
91.1
91.7
91.6
91.6
Wind
Speed
(mph)
50
60
60
60
63
75
92
98
109
119
134
150
140
140
140
140
140
140
140
140
140
115
75
50
Pressure
(millibars)
Status
(T.S. or Hurricane
& Category)
1013
1006
1007
1004
1001
994
974
974
959
951
930
923
931
932
945
945
945
949
944
937
940
954
987
991
Analysis and Conclusions
1. What is the difference between the highest and the lowest air pressure values given in the data table? Would
you expect this value to be more or less than the air pressure change across a typical mid-latitude low?
__________________________________________________________________________________
2. 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?
____________________________________________________________________________________
3. According to your graph, what is the general relationship between air pressure and wind speed?
___________________________________________________________________________________
4. How did Hurricane Andrew’s air pressure and wind speed change after both of the hurricane’s landfalls?
____________________________________________________________________________________
5. How did Hurricane Andrew’s air pressure and wind speed change after the hurricane left the west coast of
Florida and moved over water?
_________________________________________________________________________________
6. Explain why you think air pressure and wind speed are affected by the surface over which a hurricane
moves.
____________________________________________________________________________________
7. 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? Why did the hurricane’s speed change?
____________________________________________________________________________________
8. A tropical storm officially becomes a hurricane when it attains speeds greater than 74 mph. When did
Hurricane Andrew change from a tropical storm to a hurricane? When did it change back to a tropical storm?
___________________________________________________________________________________
30° N
25° N
20° N
70° W
75°
65° W
60° W
95°
90°
85°
80°