Deck 10: Thunderstorms and Tornadoes

Question 1

If you see lightning and then, 15 seconds later, hear the thunder, the lightning stroke is about ____ miles away.

A) 45
B) 15
C) 5
D) 3

Answer 1

D

Question 2

A relatively narrow downburst, less than four kilometers wide, is called a ____.

A) microburst
B) macroburst
C) funnel cloud
D) mesocyclone

Answer 2

A

Question 3

What weather system can grow to be as much as 1000 times larger in area than an ordinary cell thunderstorm, even large enough to cover an entire state?

A) overshooting thunderstorm
B) mesoscale convective complex
C) derecho
D) mesocyclone

Answer 3

B

Question 4

Beneath an intense thunderstorm, the downdraft may become localized so that it hits the ground and spreads horizontally in a radial burst of wind. This is called a ____.

A) dry line
B) outflow boundary
C) squall line
D) downburst

Question 5

Thunder is caused by ____.

A) the collision between two thunderstorms with opposite electrical charge
B) the rapid heating of air surrounding a lightning channel
C) the explosion that occurs when + and - charge collide and neutralize each other
D) turbulent wind motions inside the thunderstorm

Question 6

An ordinary cell thunderstorm is a ____.

A) thunderstorm that does not produce lightning or thunder
B) thunderstorm that has a tilted updraft and downdraft
C) scattered or isolated storm that is not severe
D) thunderstorm that does not produce hail

Question 7

Ordinary cell thunderstorms only last about one hour and begin to dissipate when ____.

A) lightning neutralizes all the electrical charge in the cloud
B) when all the precipitation particles in the cloud turn to ice
C) when the downdraft spreads throughout the cloud and cuts off the updraft
D) when solar heating at the ground begins to decrease

Question 8

The initial stage of an ordinary cell thunderstorm is the ____.

A) mature stage
B) dissipating stage
C) cumulus stage
D) multicell stage

Question 9

A small thunderstorm cloud blowing dust at the ground could warn of a severe hazard to aircraft. Why?

A) This could be the first indication of a tornado.
B) This indicates that it is likely that hail will soon begin to fall.
C) This could indicate an intense downdraft or microburst.
D) The airplane could be struck by lightning.

Question 10

What would you expect to observe during the passage of a gust front?

A) Temperatures will drop and winds will die down.
B) Temperatures will rise and winds will die down.
C) Temperatures will drop and winds will become strong and gusty.
D) Temperatures will rise and winds will become strong and gusty.

Question 11

A line of thunderstorms that forms ahead of an advancing cold front is called a ____.

A) squall line
B) wall cloud
C) gust front
D) dry line

Question 12

A group of thunderstorms that develop next to one another, each in a different stage of development, is called a(n) ____.

A) ordinary thunderstorm
B) thunderstorm cluster
C) multicell thunderstorm
D) mature thunderstorm

Question 13

Many flash floods, including those that occurred over parts of New England and the mid-Atlantic states during June 2006, and in Colorado's Big Thompson Canyon in July 1976, are the result of thunderstorms that ____.

A) contain no lightning
B) form in a dry air mass
C) move slowly
D) have weak or non-existent downdrafts

Question 14

The majority of lightning strikes occur ____.

A) from a cloud to the ground
B) from one cloud to another cloud
C) from a cloud to the surrounding air
D) within a cloud

Question 15

The greatest annual number of thunderstorms in the United States occurs in ____.

A) the Ohio valley
B) the Central Plains
C) Florida
D) Texas

Question 16

Occasionally, an elongated ominous-looking cloud forms just behind a gust front. This type of cloud, which appears to slowly spin about a horizontal axis, is called a ____.

A) downburst
B) shelf cloud
C) wall cloud
D) roll cloud

Question 17

A supercell storm is a(n) ____.

A) multicell thunderstorm that forms as a line of thunderstorms
B) number of individual multicell thunderstorms that organize into a large convective weather system
C) elongated, ominous-looking storm cloud that forms just behind a gust front
D) intense long-lasting thunderstorm with a single violently rotating updraft

Question 18

The leading edge of a thunderstorm's cold outflowing air is known as a ____.

A) downburst
B) squall line
C) gust front
D) dry line

Question 19

The downdraft in an ordinary cell thunderstorm is created mainly by ____.

A) the melting of snow in the anvil
B) electrical attraction between the cloud and ground
C) the release of latent heat as water in the cloud freezes
D) evaporating raindrops that make the air cold and heavy

Question 20

The top of a thunderstorm is normally ____ charged, and the middle and lower parts are ____ charged.

A) negatively; negatively
B) negatively; positively
C) positively; positively
D) positively; negatively

Question 21

____ measures the speed at which precipitation is moving toward or away from an antenna.

A) A radiosonde
B) An anemometer
C) A wind psychrometer
D) Doppler radar

Question 22

A hook-shaped echo on a radar screen often indicates ____.

A) a thunderstorm with very frequent lightning
B) a developing hurricane
C) the possible presence of a tornado-producing thunderstorm
D) a rotating anvil cloud at the top of a thunderstorm

Question 23

You are generally safe inside an automobile during a lighting storm because ____.

A) the car's radio antenna will act as a lightning rod
B) the rubber tires insulate you from the ground
C) metal cars do not become electrically charged
D) the metal car body will carry the lightning current around the passengers inside

Question 24

The so-called Tornado Belt, or Tornado Alley, of the United States is located ____.

A) in Florida
B) in the Central Plains
C) in the middle Atlantic states
D) along the Gulf Coast

Question 25

The signal detected by a Doppler radar is a ____.

A) microwave emitted by lightning
B) sound wave produced by thunder
C) microwave reflected by precipitation
D) sound wave produced by wind shear

Question 26

When caught in a thunderstorm in an open field, what action is best to take?

A) Seek shelter under the nearest tree.
B) Lie down flat on the ground.
C) Crouch down as low as possible while minimizing contact with the ground.
D) Remove all metallic objects from your pockets.

Question 27

On a Doppler radar screen, a tornado might appear as a region of ____.

A) low pressure
B) intense precipitation
C) rapidly changing wind directions
D) intense lightning activity

Question 28

Tornadic thunderstorms that form ahead of an advancing cold front most often travel from ____.

A) north to south
B) northwest to southwest
C) southwest to northeast
D) southeast to northwest

Question 29

When tornadoes are likely to form during the next few hours, a ____ is issued to notify the public.

A) tornado alarm
B) tornado alert
C) tornado warning
D) tornado watch

Question 30

Most tornadoes have winds that are ____.

A) greater than 500 knots
B) greater than 220 knots
C) between 125 and 220 knots
D) less than 125 knots

Question 31

In the United States, dryline thunderstorms are most common ____.

A) in the Rocky Mountains
B) in the desert southwest
C) in the Great Plains
D) in California

Question 32

If a tornado is rotating in a counterclockwise direction and moving toward the northeast, the strongest winds will be on its ____ side.

A) southwestern
B) southeastern
C) northeastern
D) northwestern

Question 33

What type of rotating cloud develops from a funnel cloud or tornado and extends beneath a severe thunderstorm?

A) mammatus cloud
B) roll cloud
C) wall cloud
D) suction vortices

Question 34

A cloud-to-ground lightning discharge will sometimes appear to flicker. This is because ____.

A) you are able to see the separate steps of the stepped leader
B) you are able to distinguish separate return strokes
C) the bright light causes you to blink
D) of refraction caused by turbulent thunderstorm winds

Question 35

Which statement about tornadoes is correct?

A) All tornadoes rotate in a counterclockwise direction.
B) Tornadoes never strike the same place twice.
C) All tornadoes make a distinctive roar.
D) The United States has more tornadoes than any other country in the world.

Question 36

The Enhanced Fujita scale pertains to the ____.

A) size of a tornado producing thunderstorm
B) amount of hail that falls from a mature thunderstorm
C) size of the thunderstorm image on a radar screen
D) wind speed of a tornado

Question 37

A rotating column of air that is connected to a cumuliform cloud over a large body of water is a ____.

A) tornado outbreak
B) roll cloud
C) microburst
D) waterspout

Question 38

A Doppler radar determines precipitation ____ by measuring changes in the ____ of the reflected radio wave.

A) size; intensity
B) velocity; intensity
C) velocity; frequency
D) size; frequency

Question 39

What is the most accurate description of the principle of a lightning rod?

A) The lightning rod acts to discharge the thunderstorm.
B) The lightning rod intercepts the lightning and safely carries the lightning current around the object it protects.
C) Lightning rods have been used since the 1700s, but the principle of their operation is not known.
D) A positive charge induced in the lightning rod repels the negative charge in an approaching step leader.

Question 40

A tornado cloud that does not touch the ground is called a ____.

A) funnel cloud
B) wall cloud
C) roll cloud
D) mesocyclone

Question 41

Instructions: Choose one answer from each pair of selections. Potentially the strongest and longest-lived thunderstorm is one with a VERTICAL | TILTED updraft.

Question 42

Instructions: Choose one answer from each pair of selections. The strongest tornadoes in the United States occur in the SPRING | FALL.

Question 43

Instructions: Choose one answer from each pair of selections. An anvil cloud forms near the top of a thunderstorm where the thunderstorm cloud reaches a STABLE | UNSTABLE region of the atmosphere.

Question 44

Instructions: Choose one answer from each pair of selections. In ordinary cell thunderstorms, when the downdraft begins to expand laterally in the cloud, the thunderstorm will usually begin to STRENGTHEN | WEAKEN.

Question 45

Instructions: Choose one answer from each pair of selections. If you are caught outside during a lighting storm, an automobile would be a GOOD | BAD place to seek shelter.

Question 46

Instructions: Choose one answer from each pair of selections. Squall line thunderstorms will often form 100 to 300 km AHEAD OF | BEHIND a cold front.

Question 47

What might you expect to see and feel if a gust front were to approach and pass you on the ground?

Question 48

Even if distinctive features that might indicate a tornado are observed on radar, a tornado must be observed visually before a tornado warning is issued.

Question 49

In some situations, individual thunderstorms may organize into a convective weather system that may be 1000 times larger than an individual storm.

Question 50

What is a gust front?

Question 51

What are microbursts?

Question 52

What is a dryline and where do they tend to occur most often in the United States?

Question 53

When the air is dry, tornadoes can remain invisible until they reach the ground and pick up dust.

Question 54

Instructions: Choose one answer from each pair of selections. Evaporating precipitation beneath a thunderstorm will STRENGTHEN | WEAKEN the downdraft.

Question 55

Instructions: Choose one answer from each pair of selections. In an average year you would expect the highest incidence of severe thunderstorms in FLORIDA | OKLAHOMA.

Question 56

Instructions: Choose one answer from each pair of selections. The greatest potential for flooding is with thunderstorms that are FAST | SLOW moving.

Question 57

Instructions: Choose one answer from each pair of selections. Florida has MORE | FEWER thunderstorms in an average year than Oklahoma.

Question 58

Weak tornadoes sometimes form along a thunderstorm gust front.

Question 59

Most cloud-to-ground lightning flashes consist of a single return stroke.

Question 60

Differentiate between tornado families and tornado outbreaks.

Question 61

What are the three basic ingredients of all thunderstorms? Describe at least three potential forcing mechanisms.

Question 62

How do flash floods differ from river floods?

Question 63

Briefly describe the three primary stages of a tornado life cycle.

Question 64

Why is it not a good idea to seek shelter from a thunderstorm beneath a tree?

Question 65

What is a squall line? Where would you expect squall lines to form?