Deck 15: Tornadoes

Question 1

A horizontal tube of spinning air, created by vertical wind shear, causes the air near the surface to rotate about a horizontal axis, and is called a mesocyclone.​

Answer 1

False

Question 2

A system called Doppler lidar uses a light beam to measure the change in frequency of falling precipitation, cloud particles, and dust.​

Answer 2

True

Question 3

The strength of a rear-flank downdraft is driven by the amount of precipitation-induced cooling in the upper levels of the storm.​

Answer 3

True

Question 4

Tornado frequency is highest during the spring and lowest during the winter when the warm surface air is normally absent.​

Question 5

Gustnadoes form along a gust front where the cool downdraft of a thunderstorm forces warm, humid air upwards.

Question 6

As the air beneath a funnel cloud is drawn into its core, the air cools rapidly and its moisture condenses, and the funnel cloud ascends away from the surface.​

Question 7

Sometimes the air is so dry that swirling, rotating wind remains invisible until it reaches the ground and begins to pick up dust, called dust devils

Question 8

A tornado warning is issued by the Storm Prediction Center to alert the public that tornadoes may develop within a specific area during a certain time period.​

Question 9

Opening windows during a tornado decreases the pressure on the opposite wall and therefore decreases the chances that the building will collapse.​

Question 10

The most severe tornado outbreaks are typically very well predicted.​

Question 11

Tornadoes that form ahead of an advancing cold front tend to move from the ____.​

A) ​northeast toward the southwest
B) ​southwest toward the northeast
C) ​northwest toward the southwest
D) ​southeast toward the northwest
E) ​northeast toward the northwest

Question 12

The final stage of a tornado's life cycle is called the shrinking stage, when usually the tornado stretches into the shape of a rope.

Question 13

The diameter of most tornadoes is between ______.​

A) ​1 to 2 miles
B) ​2 to 5 miles
C) ​50 to 100 ft
D) ​300 to 2000 ft
E) ​1000 to 3000 ft

Question 14

The belt of tornadoes that occur over Mississippi and Alabama is sometimes called tornado alley.​

Question 15

No country experiences more tornadoes than the United States.​

Question 16

All tornadoes come from rotating thunderstorms.​

Question 17

The longest tornado damage path recorded anywhere on Earth extended 352 km (219 mi).​

Question 18

Tornadoes have occurred in every state, including Alaska and Hawaii.​

Question 19

The first stage of a tornado's life cycle is the organizing stage.

Question 20

Even the most powerful twisters seldom have winds exceeding 220 knots.​

Question 21

When a tornado is approaching from the southwest, its strongest winds are on its ____ side.​

A) ​northeast
B) ​southeast
C) ​northwest
D) ​north
E) ​west

Question 22

When a large number of tornadoes develop in association with a particular weather system (typically six tornadoes or more), it is referred to as a ____.​

A) ​megacyclone
B) ​mesocyclone
C) ​tornado family
D) ​tornado epidemic
E) ​tornado outbreak

Question 23

The most frequent time of day for tornadoes to form is in the ____.​

A) ​early morning just after sunrise
B) ​late morning just before noon
C) ​evening just after sunset
D) ​late afternoon
E) ​middle of the night

Question 24

No country experiences more tornadoes than ____.​

A) ​China
B) ​South Africa
C) ​the United States
D) ​Brazil
E) ​Russia

Question 25

The first stage of a tornado life cycle is the ____ stage.​

A) ​dust-whirl
B) ​organizing
C) ​mature
D) ​shrinking
E) ​decay

Question 26

According to the Enhanced Fujita Scale, an ____ tornado causes only minimal damage, whereas an ____ completely demolishes a house and sweeps it off its foundation.​

A) ​EF0; EF3
B) ​EF1; EF5
C) ​EF0; EF5
D) ​EF1; EF4
E) ​EF2; EF3

Question 27

In which of the following states has a tornado never occurred?​

A) ​Alaska
B) ​Hawaii
C) ​Maine
D) ​North Dakota
E) ​tornadoes have occurred in every state

Question 28

Once a tornado is spotted, either visually or on a radar screen, a tornado ____ is issued by the local National Weather Service (NWS) office.​

A) ​prediction
B) ​alert
C) ​warning
D) ​watch
E) ​emergency

Question 29

During the ____, tornadoes are most likely to form over the southern Gulf states when the polar-front jet is above this region.

A) ​late spring
B) early spring​
C) ​autumn
D) ​winter
E) ​summer

Question 30

The Central Plains region is susceptible to tornadoes because ____.​

A) ​cool, dry surface air is overlain by warmer, more humid air aloft
B) ​warm, humid surface air is overlain by cooler, drier air aloft
C) ​cool, wet surface air is overlain by warmer, drier air aloft
D) ​warm, dry surface air is overlain by cooler, wetter air aloft
E) ​warm, humid surface air is overlain by even warmer, and more humid air aloft

Question 31

Violent tornadoes (with winds exceeding 180 knots) that contain smaller whirls rotating within them are called ____.​

A) ​multi-vortex tornadoes
B) ​supercell tornadoes
C) ​suction tornadoes
D) ​tornado families
E) ​tornado outbreaks

Question 32

Opening windows during a tornado increases the pressure on the opposite wall and ____.​

A) ​decreases the chances that the building will collapse
B) ​increases the chances that the building will collapse
C) ​does not influence whether the building will collapse
D) ​increases the chances of flying debris shattering the window
E) ​decreases the chances of flying debris shattering the window

Question 33

In the United States, tornadoes are most frequent during the ____, and least frequent during the ____.​

A) summer; fall
B) ​spring; winter
C) ​spring; fall
D) ​summer; winter
E) ​winter; fall

Question 34

The deadliest tornadoes are those that occur ____.​

A) ​over large distances
B) ​over long periods of time
C) ​in families
D) ​in outbreaks
E) ​in epidemics

Question 35

About 70 percent of all tornadoes in the United States develop from ____.​

A) ​May to June
B) ​March to July
C) ​March to May
D) ​April to August
E) ​April to June

Question 36

Even the most powerful twisters seldom have winds exceeding ____ knots.​

A) ​90
B) ​125
C) ​220
D) ​300
E) ​410

Question 37

Damage from a tornado is normally most severe during the ____ stage.​

A) ​dust-whirl
B) ​organizing
C) ​mature
D) ​shrinking
E) ​decay

Question 38

The Enhanced Fujita scale classifies tornadoes according to the ____ of the tornado.​

A) ​wind direction
B) ​rotational wind speed
C) ​vertical wind speed
D) ​diameter and height
E) ​length of the path of damage

Question 39

If you are driving in a car and a tornado is still at some distance, you should drive ____.​

A) ​into a ditch and cover your head
B) ​under a freeway overpass
C) ​at a right angle to the tornado's path
D) ​parallel to the tornado's path
E) ​toward the tornado

Question 40

The tornado alley of the United States ____.​

A) ​stretches from North Dakota to southern Texas
B) ​stretches from the Rocky Mountains to the Mississippi River
C) ​stretches from central Texas to Nebraska
D) ​occurs over Mississippi and Alabama
E) ​occurs over the Gulf Coast states

Question 41

A(n) ____ atmosphere is essential for tornado development.​

A) ​absolutely stable
B) ​conditionally stable
C) ​conditionally unstable
D) ​unconditionally stable
E) ​unconditionally unstable

Question 42

​Tornadoes that form along a gust front are commonly called ____.

A) ​invisible tornadoes
B) ​dust devils
C) ​false tornadoes
D) ​windnadoes
E) ​gustnadoes

Question 43

As warm, humid air is drawn into a supercell tornado, it ____ as it rises.​

A) ​becomes a rear-flank downdraft
B) ​becomes a front-flank downdraft
C) ​spins counterclockwise
D) ​spins clockwise
E) ​spins erratically

Question 44

Heavy rain-chilled air descends along a tornado as a strong downdraft called the ____.​

A) ​backwards downdraft
B) ​supercell downdraft
C) ​forward-flank downdraft
D) ​rear-flank downdraft
E) ​backdraft

Question 45

If the updraft in a supercell is so strong that precipitation cannot fall through it, southwesterly winds aloft usually blow precipitation ____.​

A) ​northwestward
B) ​southwestward
C) ​northeastward
D) ​southeastward
E) ​straight westward

Question 46

The Storm Prediction Center issues convective outlooks each day that show where outbreaks of severe weather and tornadoes are possible over the next ____.​

A) ​month
B) ​two weeks
C) ​eight days
D) ​four days
E) ​day

Question 47

​When a rear-flank downdraft strikes the ground, it may interact with a(n) ____ beneath a mesocyclone to initiate tornadogenesis.

A) ​updraft
B) ​forward-flank downdraft
C) ​vortex tube
D) ​suction vortex
E) ​jetstream

Question 48

If a downdraft is too ____, it may inhibit the lifting needed for tornado formation.​

A) ​cold and strong
B) ​cold and weak
C) ​warm and strong
D) ​warm and weak
E) ​humid and weak

Question 49

When vertical wind shear causes air near the surface to rotate about a horizontal axis, ___ are created.​

A) ​mesocyclone
B) ​vortex tubes
C) ​suction vortices
D) ​funnel clouds
E) ​nonsupercell tornadoes

Question 50

On the Doppler radar screen, the rotating precipitation around a mesocyclone may appear as a(n) ____.​

A) ​straight line
B) ​suction vortex
C) ​hook echo
D) ​anvil
E) ​cloud

Question 51

The longest tornado damage path recorded anywhere on Earth extended ____ miles.​

A) ​38
B) ​76
C) ​145
D) ​190
E) ​219

Question 52

If vertical stretching causes a spinning column of air to rise and spin faster, the rapidly rotating air column may shrink into a ____.​

A) ​mesocyclone
B) ​tornado vortex
C) ​suction vortex
D) ​dust devil
E) ​downdraft

Question 53

If the air is so dry that the swirling, rotating wind remains invisible until it reaches the ground and picks up dust, it is referred to as a(n)____.​

A) ​invisible tornado
B) ​dust devil
C) ​cyclone
D) ​fair-weather tornado
E) ​nonsupercell tornado

Question 54

To an observer on the ground, the first sign that a supercell may give birth to a tornado is the sight of ____.​

A) ​a mesocyclone
B) ​a funnel cloud
C) ​rotating clouds near the middle of the storm
D) ​rotating clouds at the base of the storm
E) ​rotating clouds at the top of the storm

Question 55

Tornadoes that do not occur in association with a mid-level mesocyclone of a supercell are called ____.​

A) ​megacyclones
B) ​funnel clouds
C) ​nonsupercell tornadoes
D) ​quasi-tornadoes
E) ​tornado vortices

Question 56

As air rushes upward and spins around a low-pressure core of the vortex, the air expands, cools, and, if sufficiently moist, condenses into a ____.​

A) ​suction vortex
B) ​mesocyclone
C) ​vortex tube
D) ​tornado vortex
E) ​funnel cloud

Question 57

Most often, tornadoes form with supercell thunderstorms in an environment with strong ____.​

A) ​radiational cooling
B) ​precipitation
C) ​vertical wind shear
D) ​horizontal wind shear
E) ​suction vortices

Question 58

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

A) ​cumulus tornado
B) ​waterspout
C) ​landspout
D) ​spicket tornado
E) ​funnel cloud

Question 59

If an updraft tilts a rotating tube of air and draws it into a storm, the tilted, rotating tube becomes part of the storm's structure, called the ____.​

A) ​bounded weak echo region
B) ​mesocyclone
C) ​megacyclone
D) ​vortex tube
E) ​low-level jet stream

Question 60

Landspouts are weak, short-lived tornadoes that occur with rapidly building ____ clouds in places such as the High Plains.​

A) ​cumulus congestus
B) ​cumulus fractus
C) ​altocumulus
D) ​cirrocumulus
E) ​nimbostratus

Question 61

When a large number of tornadoes develop in association with a particular weather system (typically six tornadoes or more, although there is no strict definition), it is referred to as a(n) ____________________.​

Question 62

The network of more than 150 Doppler radar units deployed at selected weather stations within the continental United States is referred to as ____.​

A) ​NEXRAD
B) ​Doppler Lidar
C) ​National Weather Service
D) ​NOAA
E) ​the Enhanced Fujita System

Question 63

The belt of tornadoes that occur over Mississippi and Alabama is sometimes called ____________________.

Question 64

To help distinguish a storm's air motions, a Doppler radar can display ____​

A) ​amount of radiational cooling
B) ​wind velocities in color
C) ​lightning streaks
D) ​funnel clouds
E) ​the amount of solar energy of a given area

Question 65

The original Fujita scale, implemented in 1971, was based mainly on tornado damage incurred by a(n) ____________________.​

Question 66

When a tornado is approaching from the southwest, its strongest winds are on its ____________________ side.

Question 67

A tornado ____________________ is issued once a tornado is spotted, either visually or on a radar screen.​

Question 68

The final stage of a tornado life cycle is called the ____________________ stage, when usually the tornado is stretched into the shape of a rope.

Question 69

The next advance in Doppler radar technology is the polarimetric radar that transmits ____.​

A) ​a horizontal radar pulse
B) ​a vertical radar pulse
C) ​both a horizontal and a vertical radar pulse
D) ​light beams
E) ​radar pulses specifically in the polar regions

Question 70

The deadliest tornadoes are those that occur in ____________________, which is a group or series of tornadoes spawned by the same thunderstorm.

Question 71

Doppler radar works on the principle that, as precipitation moves toward or away from the antenna, the ____.​

A) ​light beam will measure the wind speed of tornadoes
B) ​light beam will measure the change in frequency of falling precipitation
C) ​returning radar pulse will change color compared to the transmitted frequency
D) ​returning radar pulse will change frequency compared to the transmitted frequency
E) ​returning radar pulse will be the same frequency as the transmitted frequency

Question 72

The wisest course to take when confronted with an approaching tornado is to ____________________.

Question 73

In recent years, most of our knowledge about what goes on inside a tornado-generating thunderstorm has been gathered through the use of ____.​

A) ​vortex chambers
B) ​spotter networks
C) ​algorithms
D) ​Doppler radar
E) ​storm chasers

Question 74

Most often, tornadoes form with supercell thunderstorms in an environment with strong ____________________.​

Question 75

​A system called ____ uses a light beam to measure the change in frequency of falling precipitation, cloud particles, and dust.

A) ​Doppler radar
B) ​Doppler lidar
C) ​the vortex chamber
D) ​dual polarization radar
E) ​NEXRAD

Question 76

Studies conducted since the 1970s reveal that most tornadoes have winds of less than ____________________ knots.

Question 77

​With the Doppler radar, a radar transmitter sends out ____, and when they strike an object, some are reflected and scattered back to the antenna.

A) ​microwave pulses
B) ​laser beams
C) ​soundwaves
D) ​ultraviolet lightwaves
E) ​light beam

Question 78

The region inside the supercell where radar is unable to detect precipitation is known as the ____________________.​

Question 79

When the rear-flank downdraft strikes the ground, it may interact with the forward-flank downdraft beneath the mesocyclone to initiate _______________.​

Question 80

​Doppler radar can measure ____.

A) ​rainfall intensity
B) ​the speed at which precipitation is moving horizontally
C) ​rainfall intensity and the speed at which precipitation is moving horizontally
D) ​wind speeds of small tornadoes
E) ​forecasted storm cells