1

National Science Olympiad

Meteorology (Severe Storms) 2011

Instructions: Remember, you have 50 minutes, so use your time wisely. Please write all of your answers on the answer sheet provided. If you don’t know the answer to a question, you may wish to skip it and go on. An announcement will go out when 30 minutes, 15 minutes, and 5 minutes remain. If you finish early, you may wish to check over your answers. Remember to include units in your answers! You may use one 8.5 X 11” page of notes, front and back. If you have any questions, or are concerned about anything, please ask one of the event supervisors for help. Good luck and have fun! Remember to write your names and school in the blanks provided on your answer sheet.

2

1. Use the maps of tornado occurrence by state to answer the following questions.

3

a. How many states had an average of more than 5.0 tornadoes per 10,000 square miles? _______________________________________________________________________

b. How many states averaged 0.0 strong tornadoes per 10,000 square miles? _______________________________________________________________________

c. Rank the following states in order from most to fewest tornadoes per 10,000 square miles.

Texas Wyoming Iowa Florida Hawaii

________________________________________________________________________

d. Which of the following states had the most strong tornadoes? Circle one.

Indiana Nebraska Mississippi Florida

e. Draw a line around the states that had more than 1 strong tornado per 10,000 square miles.

4

2. Given the National Weather Service Warning text below (in bold font), answer the following questions: BULLETIN - EAS ACTIVATION REQUESTED TORNADO WARNING NATIONAL WEATHER SERVICE CHARLESTON SC 725 PM EDT SAT MAR 26 2011 THE NATIONAL WEATHER SERVICE IN CHARLESTON HAS ISSUED A * TORNADO WARNING FOR... NORTHERN BULLOCH COUNTY IN SOUTHEAST GEORGIA... EXTREME NORTH CENTRAL CANDLER COUNTY IN SOUTHEAST GEORGIA... SOUTHERN JENKINS COUNTY IN SOUTHEAST GEORGIA... SCREVEN COUNTY IN SOUTHEAST GEORGIA... * UNTIL 815 PM EDT * AT 724 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A SEVERE THUNDERSTORM CAPABLE OF PRODUCING A TORNADO 8 MILES SOUTHWEST OF BUTTS...MOVING EAST AT 45 MPH. * SOME LOCATIONS IN THE WARNING INCLUDE... BUTTS...EMMALANE...PORTAL...SCARBORO...HOPEULIKIT...ROCKY FORD... MIDDLEGROUND...DOVER...WOODCLIFF... PRECAUTIONARY/PREPAREDNESS ACTIONS... THIS TORNADO MAY BE WRAPPED IN RAIN AND NOT EASILY SEEN. IF YOU WAIT UNTIL YOU SEE OR HEAR IT COMING IT MAY BE TOO LATE. TAKE SHELTER NOW.

5

a. When was the tornado warning issued? ________________________________________________________________________

b. Until when is it valid? ________________________________________________________________________

c. Why was the warning issued? ________________________________________________________________________

d. What direction and how fast is the storm moving? _______________________________________________________________________

e. Are there any special concerns for this warning? If so, what? _______________________________________________________________________

f. For what counties is the warning valid? _______________________________________________________________________

g. What weather service office issued the warning?

_______________________________________________________________________

6

3. The following diagram is a surface map of a common weather set-up in the Midwest during the Spring and Summer. The ‘L’ represents the center of low surface pressure, the numbers in black are temperatures, and the numbers in gray are dewpoint temperatures. Severe weather forecasters use large differences in surface temperatures to find the locations of cold and warm fronts, and use dewpoint temperatures to identify large differences in moisture. On the diagram below, use the temperatures and dewpoints to draw the location of the cold front, warm front, and dry line on the map. Use the proper symbols for the cold front and warm front, and a dashed line for the dry line.

7

4. The picture below is a drawing of a mature supercell thunderstorm. Use it to answer the questions below.

a. Using arrows, draw the location of the storm’s updraft and downdraft on the diagram. b. Label the ‘overshooting top,’ ‘anvil,’ and ‘wall cloud’ on the diagram. c. If a tornado were to form from this supercell thunderstorm, illustrate where it would

form on the diagram.

8

5. The two maps below show the RETURN PERIOD for category 1 and category 5 hurricanes, respectively, along the United States Gulf Coast. Use those maps to answer the following questions.

A

B

D

C

A

B

D

C

9

a. What is the return period for a category 1 hurricane to hit point A?

________________________________________________________________________

b. A higher return period means an event is more or less common? ________________________________________________________________________

c. Which letter, A-D, represents the greatest risk of a category 5 hurricane hitting at that point? ________________________________________________________________________

d. Which letter, A-D, represents the least risk of a category 5 hurricane hitting at that point? ________________________________________________________________________

6. The wind speed estimates for the EF scale are 3-second gusts. Normal wind speeds are 1-minute averages.

a. Which would you expect to be higher? Circle one.

3-second EF scale gusts Normal 1-minute average

b. Why did you circle the choice in part (a)? ________________________________________________________________________

7. Your friend tells you that she just heard there is a tornado watch that includes the city of Chicago. What does this mean? Circle the best answer. a) A tornado has been spotted in Chicago by a storm spotter. b) A tornado has shown up on radar (over Chicago), but not verified by a person. c) Weather conditions favor the development of a tornado in or near Chicago in the next

several hours. d) A tornado will certainly develop just outside of Chicago, just you wait.

8. Which of the following is not a tropical cyclone? Circle the best answer.

a) Hurricane

b) Nor’easter

c) Typhoon

d) Cyclones

10

9. If you are outside and no shelter is available when a thunderstorm suddenly forms, what is

the safest position to take to minimize the chances of being struck by lightning? Circle one.

a) Lying flat on the ground.

b) Standing as straight as possible.

c) In a “plank position”, with your hands on the ground, similar to a “push-up”.

d) Squatting low, on the balls of your feet, if possible.

10. A cold front is formed by a clash of two air masses, typically a continental _______ air mass

and a ___________ tropical air mass. Circle the combination of words that would best fill in

the blanks above (in order).

a) Tropical, Polar

b) Polar, Maritime

c) Dry, Stormy

d) Tropical, Maritime

True or False. Evaluate whether the following statements are true or false, then circle the

correct answer below.

11. All derechos are a type of bow echo but not all bow echoes are derechos.

True False

12. Overpasses are a safe place to take shelter from a tornado.

True False

13. Lightning never strikes twice in the same place.

True False

14. Tornadoes have happened in each of the 50 U.S. States.

True False

11

15. The center of a hurricane is known as the “lull”.

True False

16. Every mature thunderstorm cell consists of an updraft and a downdraft.

True False

17. Many scientists think cloud seeding can reduce crop damage made by hailstones by

creating significantly fewer hailstones, even if each stone is larger.

True False

18. All hailstones that fall out of the same thunderstorm at the same time are the exact same

size.

True False

19. A car can be swept away by only a few inches of moving flood water covering the roadway.

True False

20. Dry lines involve less dense, moist air being lifted by denser, dry air.

True False

21. Hurricanes can form on the equator.

True False

12

22. Rank the following types of severe weather from most (1) to least (4) deadly, on average,

in the United States.

Tornadoes Hurricanes Lightning Flash Flooding

1) _______________________________________________________________

2) _______________________________________________________________

3) _______________________________________________________________

4) _______________________________________________________________

23. For the following two questions (a) and (b), refer to the image below.

13

a. Is there a tornado in the above image?

Yes No

b. Why or why not? _______________________________________________________________________

24. Computing tornado probabilities. Several of the questions below ask you to compute

results. Be sure to show your work, include proper units (if applicable), and circle your

final answer.

a. Calculate the area of a tornado that is 1 mile wide. Assume the tornado is a perfect

circle (A = pi * r^2) and that the value of pi is 3.14.

b. Now, approximate the area covered by the tornado if it travels in a path 10 miles long.

c. Assume that the state of Colorado is a rectangle 380 miles long and 280 miles wide.

What is the area of the state?

d. How many tornado tracks of the type described in part (b) could fit in the state?

e. What does this say about the odds of this tornado hitting any one city in the state?

_______________________________________________________________________

25. Describe briefly how hail forms in a thunderstorm.

__________________________________________________________________________

14

26. A hail stone will fall out of a thunderstorm when which of the following scenarios occur?

Circle the best answer.

a) The updraft strengthens.

b) The updraft weakens.

c) The weight of the stone is great enough to overcome the updraft.

d) Either ‘b’ or ‘c’.

e) None of the above because hail falling out of a thunderstorm is completely random.

27. Match the following words with their National Weather Service definitions by writing the

abbreviation for the watch/warning type (in bold) next to its definition:

Flood Watch (FW) Flash Flood Warning (FFW) Flash Flood Watch (FFA) Flood Advisory (FA)

_______________ Thunderstorms have produced heavy rainfall that may result in ponding of water on roadways and in low-lying areas which does not pose an immediate threat to life and property. _______________ Atmospheric and hydrologic conditions are favorable for short duration flash flooding and/or dam break is possible. _______________ Excessive rainfall producing thunderstorms have developed, leading to short duration flooding. _______________ Atmospheric and hydrologic conditions are favorable for long duration areal or river flooding.

15

28. The map below shows locations where air masses affecting North America form. For each location, A-G, match the location with the air mass originating there by writing the appropriate number from the right in the blank on the left. Some names may be used more than once. Bonus: include the proper abbreviation for each air mass.

A. ____________________________

B. ____________________________

C. ____________________________

D. ____________________________

E. ____________________________

F. ____________________________

G. ____________________________

1. Maritime Polar 2. Maritime Tropical

3. Continental Polar 4. Continental Arctic 5. Continental Tropical

16

29. Which of the following cloud(s) produce(s) rain? Circle all that apply. a) Cirrus b) Altostratus c) Nimbostratus d) Altocumulus e) Cumulonimbus

30. Which of the following statements about a cloud that produces lightning are (is) true? Circle all that apply. a) The cloud must contain hail. b) The cloud cannot contain snow. c) The cloud must be precipitating. d) The cloud must extend above the freezing level of the atmosphere. e) It must be a cumulonimbus cloud.

31. Suppose you are standing in Texas at 3pm on a sunny afternoon in May. You, being a weather genius, have noticed the wind, which was from the southwest at 1pm, is now blowing out of the west. The temperature has increased from 85oF to 88oF, but the dew point temperature has dropped from 60oF to 23oF. What has happened? Circle the best answer. a) A cold front has passed. b) A dryline has passed. c) A warm front has passed. d) A high pressure system has formed overhead.

32. While on vacation with your family in Florida near the Gulf of Mexico, you see a thunderstorm rapidly develop over the Gulf, and a funnel cloud touches down on the water. Eventually the funnel moves onshore, travelling inland a few miles (keeping contact with the ground the entire time) before dissipating. How would this be classified? Circle the best answer. a) It is classified as a waterspout, since it originally touches down over the water. b) It is classified as a tornado, since it eventually moved inland. c) It is classified as both: a waterspout while on the water and a tornado while on land. d) It is classified as a ‘waternado.’ e) It is classified as a hybrid tornado.

1

National Science Olympiad

Meteorology (Severe Storms) 2011

Answer Key

Instructions: Remember, you have 50 minutes, so use your time wisely. Please write all of your answers on this answer sheet. If you don’t know the answer to a question, you may wish to skip it and go on. An announcement will go out when 30 minutes, 15 minutes, and 5 minutes remain. If you finish early, you may wish to check over your answers. Remember to include units in your answers! You may use one 8.5 X 11” page of notes, front and back. If you have any questions, or are concerned about anything, please ask one of the event supervisors for help. Good luck and have fun! Remember to write your names and school in the blanks below. Name: _______________ _________________________________________________________ Name: ________________________________________________________________________ School Name: __________________________________________________________________ School Number: ________________________________________________________________

2

1. a. 11

b. 8

c. 1) Florida (9.4) 2) Iowa (6.6) 3) Texas (5.2) 4) Hawaii (1.6) 5) Wyoming (1.1)

d. Indiana Nebraska Mississippi Florida

e.

3

2. a. 7:25 PM EDT, Saturday March 26, 2011_______________________________________

b. 8:15 PM EDT, Saturday March 26, 2011_______________________________________

c. NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A SEVERE THUNDERSTORM CAPABLE OF PRODUCING A TORNADO 8 MILES SOUTHWEST OF BUTTS

d. EAST AT 45 MPH

e. THIS TORNADO MAY BE WRAPPED IN RAIN AND NOT EASILY SEEN.

f. NORTHERN BULLOCH COUNTY IN SOUTHEAST GEORGIA EXTREME NORTH CENTRAL CANDLER COUNTY IN SOUTHEAST GEORGIA SOUTHERN JENKINS COUNTY IN SOUTHEAST GEORGIA SCREVEN COUNTY IN SOUTHEAST GEORGIA

g. Charleston, South Carolina

4

3.

5

4.

5.

a. 14 years

b. Less common

c. Letter C

d. Letter D

6. a. 3-second EF scale gusts Normal 1-minute average

Overshooting Top

Anvil

Wall Cloud

6

b. The 3-second gust would be expected to be greater because it’s a fairly instantaneous

value. Wind speed is highly variable and over a longer period of time, the highs and lows would average out, reducing it.

7.

a) A tornado has been spotted in Chicago by a storm spotter.

b) A tornado has shown up on radar (over Chicago), but not verified by a person.

c) Weather conditions favor the development of a tornado in or near Chicago in the next several hours.

d) A tornado will certainly develop just outside of Chicago, just you wait.

8.

a) Hurricane

b) Nor’easter

c) Typhoon

d) Cyclones

9.

a) Lying flat on the ground.

b) Standing as straight as possible.

c) In a “plank position”, with your hands on the ground, similar to a “push-up”.

d) Squatting low, on the balls of your feet, if possible.

10.

a) Tropical, Polar

b) Polar, Maritime

7

c) Dry, Stormy

d) Tropical, Maritime

11. True False

12. True False

13. True False

14. True False

15. True False

16. True False

17. True False

18. True False

19. True False

20. True False

21. True False

8

22.

1) Flash Flooding

2) Tornadoes

3) Lightning

4) Hurricanes

23.

a. Yes No

b. There is a debris cloud in contact with the ground. A tornado is defined as a whirling column of air stretching from a thunderstorm to the ground. Even if no condensation funnel has formed, this is still a tornado.

24.

a. Calculate the area of a tornado that is 1 mile wide.

A=0.785 mi2

9

b. Now, approximate the area covered by the tornado if it travels in a path 10 miles long.

First method (10 mi track, center to center):

A = Arectangle + Acircle A= (l x w) + 2 x (1/2 area circle)

A= (10 mi x 1 mi) + 0.785 mi2

A = 10.785 mi2

Also allowed (10 mi track, from edge to edge):

A = Arectangle + Acircle A= (l x w) + 2 x (1/2 area circle)

A= (9 mi x 1 mi) + 0.785 mi2

A = 9.785 mi2

c. What is the area of the state?

A = l x w A = 380 mi x 280 mi A = 106, 400 mi2

d. How many tornado tracks of the type described in part (b) could fit in the state?

Number of tracks = Area of State/Area of Track

N = 106,400 mi2 / 10.785 mi2 (or 9.785 mi2)

N = 9865 tracks (rounded down) or N=10873 tracks (rounded down).

10 mi

0.5 mi

9 mi

0.5 mi

10

e. The odds of a tornado like this hitting any one city in the state are very small, because

approximately 10,000 of these tornado tracks could fit in the state. Thus, more than

10,000 tornadoes would need to occur to cover everywhere, but only about 1,000

happen in a year.

25. Hail forms when water droplets are blown upward by an updraft, freeze and collect

supercooled water and then fall to a sub-freezing layer, where the outer shell melts. This

cycle of melting and refreezing occurs until the stone is too heavy to be supported by the

storm and falls to the ground.

26.

a) The updraft strengthens.

b) The updraft weakens.

c) The weight of the stone is great enough to overcome the updraft.

d) Either ‘b’ or ‘c’.

e) None of the above because hail falling out of a thunderstorm is completely random.

27. FA Thunderstorms have produced heavy rainfall that may result in ponding of water on

roadways and in low-lying areas which does not pose an immediate threat to life and

property.

FFA Atmospheric and hydrologic conditions are favorable for short duration flash flooding and/or dam break is possible. FFW Excessive rainfall producing thunderstorms have developed, leading to short duration flooding. FW Atmospheric and hydrologic conditions are favorable for long duration areal or river flooding.

11

28. A. 1. mP (maritime polar)

B. 4. cA (continental arctic)

C. 3. cP (continental polar)

D. 1. mP (maritime polar)

E. 2. mT (maritime tropical)

F. 2. mT (maritime tropical)

G. 5. cT (continental tropical)

29. a) Cirrus

b) Altostratus

c) Nimbostratus

d) Altocumulus

e) Cumulonimbus

30. a) The cloud must contain hail.

b) The cloud cannot contain snow.

c) The cloud must be precipitating.

d) The cloud must extend above the freezing level of the atmosphere.

e) It must be a cumulonimbus cloud.

12

31. a) A cold front has passed.

b) A dryline has passed.

c) A warm front has passed.

d) A high pressure system has formed overhead.

32. a) It is classified as a waterspout, since it originally touches down over the water.

b) It is classified as a tornado, since it eventually moved inland.

c) It is classified as both: a waterspout while on the water and a tornado while on land.

d) It is classified as a ‘waternado.’

e) It is classified as a hybrid tornado.