Deck 14: Thunderstorms

Question 1

In the valleys of central and southern California, dry, sinking air produces an inversion that inhibits the development of towering cumulus clouds during the summer. Hence, in these regions, thunderstorms are most frequent in winter and spring, particularly when cold, moist, conditionally unstable air aloft moves over moist, mild surface air.​

Answer 1

True

Question 2

Lightning may occur from one cloud to another.​

Answer 2

True

Question 3

When a thunderstorm is located on the high plains east of the Rocky Mountains, a much larger portion of the storm will typically be located above the freezing level, so hail has a better chance of occurring.

Answer 3

True

Question 4

Is this statement true or false: "Lightning never strikes twice in the same place"?​

Question 5

One theory for the electrification of clouds involves supercooled cloud droplets.​

Question 6

Large hail is more common in Kansas than in Florida.​

Question 7

Even though the bright return stroke of lightning travels from the ground up to the cloud, it happens so quickly that our eyes cannot resolve the motion, and we see what appears to be a continuous bright flash of light.​

Question 8

Lightning can shoot from the top of thunderstorms into the upper atmosphere.​

Question 9

Sonic booms are produced when an aircraft exceeds the speed of light at the altitude at which it is flying. The aircraft compresses the air, forming a shock wave that trails out as a cone behind the aircraft. Along the shock wave, the air pressure changes rapidly over a short distance. The rapid pressure change causes the distinct boom.​

Question 10

Scientists understand with certainty how clouds are electrified.​

Question 11

All thunderstorms require​

A) ​hot air.
B) ​divergence of the air aloft.
C) ​lifting along some barrier such as a mountain or front.
D) ​surface heating.
E) ​rising air.

Question 12

Squall-line thunderstorms often form ahead of advancing cold fronts but seldom behind them.​

Question 13

Left-moving supercell thunderstorms are uncommon in the Northern Hemisphere, yet are very common in the Southern Hemisphere.​

Question 14

To be rated a severe thunderstorm by the National Weather Service, the storm has to have at least one of the following: large hail with a diameter of at least three-quarters of an inch, surface wind gusts of 40 knots or greater, or produces a tornado.​

Question 15

Thunderstorms are a common phenomenon in areas dominated by subtropical highs.​

Question 16

One theory of cloud electrification states that during the formation of precipitation, regions of separate charge exist within tiny cloud droplets and larger precipitation particles. In the lower part of these particles we find negative charge, while in the upper part we find positive charge.​

Question 17

Positive lightning has the potential to cause more damage because it generates a much higher current level and its flash lasts for a longer duration than negative lightning.​

Question 18

Although we often see thunderstorms forming where the surface air is quite warm and humid, they may also form when the surface air temperature is 10 degrees Celsius (50 degrees Fahrenheit) or even lower.​

Question 19

In some thunderstorms, lightning is seen but thunder does not get produced by the lightning.​

Question 20

Sinking air warms, yet the downdrafts in a thunderstorm are usually cold.
​

Question 21

The wind shear associated with several major airline crashes is believed to have been caused by​

A) ​microbursts.
B) ​dry lines.
C) ​the jet stream.
D) ​mesocyclones.
E) ​the jet streak.

Question 22

The initial stage of an ordinary thunderstorm is the​

A) ​mature stage.
B) ​dissipating stage.
C) ​cumulus stage.
D) ​multicell stage.
E) ​primary stage.

Question 23

Which of the following is the least likely during the passage of a gust front?​

A) ​gusty winds
B) ​rising surface pressures
C) ​increase in temperatures
D) ​enhanced updraft
E) ​winds rapidly changing direction and speed.

Question 24

Squall lines generally do not form​

A) ​behind a cold front.
B) ​when the air aloft develops waves downwind from a cold front.
C) ​along a cold front.
D) ​in the warm sector where warm, dry air meets warm, humid air.
E) ​ahead of an advancing cold front.

Question 25

Distant lightning that is so far away you cannot hear the thunder is called​

A) ​sheet lightning.
B) ​heat lightning.
C) ​false lightning.
D) ​St. Elmo's fire.
E) ​auroral lightning.

Question 26

Electrons​

A) ​are negatively charged.
B) ​are positively charged.
C) ​carry no charge.
D) ​can carry either positive or negative charge.
E) ​go back and forth between positive, negative, and neutral.

Question 27

Downdrafts tend to dominate during the ____ stage.​

A) ​cumulus
B) ​dissipating
C) ​precipitating
D) ​developing
E) ​growth

Question 28

Squall line thunderstorms generally form​

A) ​along or ahead of a cold front.
B) ​with a strong wave cyclone.
C) ​behind a cold front.
D) ​ahead of a warm front.
E) ​along an occluded front.

Question 29

The upper part of a thunderstorm cloud is normally ____ charged, and the middle and lower parts are ____.​

A) ​negatively; neutral
B) ​negatively; positive
C) ​positively; positive
D) ​positively; negative
E) ​positively; neutral

Question 30

An ordinary thunderstorm​

A) ​does not produce lightning or thunder.
B) ​has a tilted updraft and downdraft.
C) ​is a scattered/isolated storm and normally not severe.
D) ​does not produce hail.
E) ​does not produce precipitation.

Question 31

Many flash floods, including the one that occurred in Colorado's Big Thompson Canyon, 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.
E) ​lack the dissipating stage.

Question 32

Ordinary 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.
E) ​when clouds scatter due to the microbursts within the storm system.

Question 33

An ordinary thunderstorm is most intense during the ____ stage.

A) ​mature
B) ​multicell
C) ​cumulus
D) ​dissipating
E) ​growth

Question 34

Thunderstorms that produce tornadoes​

A) ​have very little cloud-to-ground lightning.
B) ​have updraft velocities that exceed 100 miles per hour.
C) ​have rotating updrafts.
D) ​will not produce hail.
E) ​do not exist.

Question 35

The most likely time for an ordinary thunderstorm to form is​

A) ​just after sunrise.
B) ​just before sunrise.
C) ​around midnight.
D) ​late afternoon.
E) ​at noon.

Question 36

Supercell thunderstorms are different from ordinary thunderstorms in that supercell thunderstorms​

A) ​contain thunder and lightning.
B) ​have an anvil.
C) ​contain hail.
D) ​have a strong updraft and downdraft.
E) ​have a tilted updraft in the mature stage.

Question 37

The downdraft in an ordinary 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.
E) ​upper level wind motions.

Question 38

Each year, U.S. fire departments respond to more than ____ fires started by lightning in the United States.​

A) ​2,000
B) ​50,000
C) ​10,000
D) ​20,000
E) ​50,000

Question 39

During the summer, what conditions prevail near the surface over the Great Plains that help a hailstone survive as ice all the way to the ground?​

A) ​strong updrafts
B) ​weak updraftsdry air
C) ​dry air
D) ​a rapid change in pressure
E) ​a rapid change in temperature

Question 40

A small thunderstorm cloud with virga falling out of its base and blowing dust at the ground could warn of a severe hazard to an airplane because​

A) ​this could be the first indication of a tornado.
B) ​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.
E) ​a hurricane is close by.

Question 41

Floods that develop rapidly with little or no advance warning are called ____ floods.​

A) ​rapid
B) ​sudden
C) ​storm
D) ​thunderstorm
E) ​flash

Question 42

When caught in a thunderstorm in an open field, the best thing to do is to​

A) ​run for cover 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.
E) ​climb up onto a hill.

Question 43

Supercell thunderstorms differ from ordinary cell (air mass) thunderstorms because​

A) ​the updraft in a supercell thunderstorm is shorter-lasting and is stationary..
B) ​ordinary thunderstorms do not produce hail.
C) ​supercell thunderstorms produce precipitation.
D) ​the supercell thunderstorm is greater in size.
E) ​the updraft in a supercell thunderstorm is longer-lasting and rotates.

Question 44

Shelf clouds are also called ____ clouds.​

A) ​arcus
B) ​cucmulus
C) ​comma
D) ​omega
E) ​stratus

Question 45

The greatest frequency of hailstorms in the United States is

A) ​over the western Great Plains.
B) ​along the Gulf Coast.
C) ​along the east coast
D) ​in the Rocky Mountain region.
E) ​along the west coast.

Question 46

Thunder will not occur​

A) ​without lightning.
B) ​in wintertime thunderstorms.
C) ​in thunderstorms over the ocean.
D) ​when a thunderstorm is producing precipitation.
E) ​in thunderstorms without precipitation.

Question 47

The majority of lightning strikes occur within the cloud, while only about ____ percent or so occur between cloud and ground.​

A) ​5
B) ​10
C) ​15
D) ​20
E) ​25

Question 48

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.
E) ​microbursts within the atmosphere.

Question 49

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

A) ​45
B) ​15
C) ​5
D) ​3
E) ​1.5

Question 50

Clouds, which appear to slowly spin about a horizontal axis, are called ____ clouds.​

A) ​shelf
B) ​anvil
C) ​comma
D) ​arcus
E) ​roll

Question 51

In what region in the United States do dryline thunderstorms most frequently form?

A) ​Washington, Oregon
B) ​Colorado, Utah, New Mexico
C) ​Pennsylvania, Maryland, Delaware
D) ​Texas, Kansas, Oklahoma
E) ​Tennessee, Louisiana

Question 52

An important principle in one of the theories of the electrification of clouds is that

A) ​there is a net transfer of negative ions from a warmer object to a colder object.
B) ​supercooled water is always negatively charged.
C) ​ice crystals are always negatively charged.
D) ​there is a net transfer of positive ions from a warmer object to a colder object.
E) ​raindrops are always positively charged.

Question 53

When thunderstorms are passing over the same area, they are​

A) ​recurring.
B) ​practicing.
C) ​revising.
D) ​training.
E) ​repeating.

Question 54

Ordinary cell thunderstorms most frequently form​

A) ​in the morning.
B) ​at noon.at noon.
C) ​in the afternoon.
D) ​in the evening.
E) ​at night.

Question 55

The highest frequency of thunderstorms in the United States occurs in​

A) ​California.
B) ​Kansas.
C) ​Colorado.
D) ​Maine.
E) ​Florida.

Question 56

In the United States, drylines are most frequently observed in the western half of Texas, Oklahoma, and Kansas. In this region, drylines occur most frequently during spring and early summer, where they are observed about ____ percent of the time.

A) ​10
B) ​20
C) ​30
D) ​40
E) ​50

Question 57

In the United States, winter thunderstorms often occur ____ when cold air aloft moves over the region.​

A) ​in Hawaii
B) ​in the northeast
C) ​along the east coast
D) ​along the west coast
E) ​in the Gulf Coast region

Question 58

It is estimated that more than ____ thunderstorms occur each day throughout the world.​

A) ​10,000
B) ​20,000
C) ​30,000
D) ​40,000
E) ​50,000

Question 59

One of the most common times to experience a thunderstorm in parts of Iowa and Missouri is between ____ and ____.​

A) ​early morning; noon
B) ​noon; late afternoon
C) ​midnight; dawn
D) ​late afternoon; evening
E) ​evening; midnight

Question 60

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

A) ​you are able to see charges.
B) ​you are barely able to distinguish separate return strokes.
C) ​the bright light causes you to blink.
D) ​of refraction caused by turbulent thunderstorm winds.
E) ​your eyes momentarily get blinded by lightning.

Question 61

If thunderstorms bring repeated heavy rain to a region for days or weeks, the result can be one or more ____________________ floods.​

Question 62

Scattered thunderstorms (sometimes called "pop-up" or "popcorn" storms) that typically form on warm, humid days are often referred to as ____________________ thunderstorms or ____________________ thunderstorms.​

Question 63

Sound travels ____________________ in warm air than in cold air.​

Question 64

____________________ is a discharge of electricity, a giant spark, which usually occurs in mature thunderstorms.​

Question 65

The high winds behind a strong gust front are called ____________________ winds to distinguish them from the rotating winds of a tornado.​

Question 66

Positive lightning is the most common with ____ thunderstorms.​

A) ​ordinary cell
B) ​squall-line
C) ​multicell
D) ​supercell
E) ​mesoscale convective complex

Question 67

A lightning flash consisting of many strokes usually lasts less than ____ second.

A) ​one
B) ​three
C) ​five
D) ​seven
E) ​nine

Question 68

____ lightning looks like a luminous sphere, often about the size of a football, that appears to float in the air or slowly dart about for several seconds​

A) ​Ball
B) ​Bead
C) ​Ribbon
D) ​Forked
E) ​St. Elmo's

Question 69

Thunderstorms may form along or just east of a boundary called a(n) ____________________, which represents a narrow zone where there is a sharp horizontal change in moisture.

Question 70

For ____ to occur, separate regions containing opposite electrical charges must exist within a cumulonimbus cloud.​

A) ​lightning
B) ​thunder
C) ​sonic boom
D) ​hail during a thunderstorm
E) ​tornadoes

Question 71

Cloud-to-ground lightning begins within the cloud when the localized electric potential gradient exceeds ____ volts per meter along a path perhaps 50 m long.

A) ​300
B) ​3,000
C) ​30,000
D) ​300,000
E) ​3 million

Question 72

When damage associated with straight-line winds extends for several hundred kilometers along the path of a squall line, the storm is called a(n) ____________________.

Question 73

Thunderstorms are ____________________ storms that form with rising air.​

Question 74

​About ____ percent of all cloud-to-ground lightning is negative.

A) ​90
B) ​70
C) ​50
D) ​30
E) ​10

Question 75

Typically, a lightning flash will have ____ leaders, each followed by a return stroke.​

A) ​one or two
B) ​two or three
C) ​three or four
D) ​four or five
E) ​five or six

Question 76

The lightning stroke can heat the air through which it travels to an incredible 30,000 degrees Celsius (54,000 degrees Fahrenheit), which is ____ times hotter than the surface of the Sun.​

A) ​2
B) ​3
C) ​4
D) ​5
E) ​6

Question 77

A thunderstorm is a storm containing ____________________ and ____________________.​

Question 78

When a dart leader moving toward the ground deviates from the original path taken by the stepped leader, the lightning appears crooked. Lightning that takes on this shape is called ____ lightning.​

A) ​ribbon
B) ​forked
C) ​crooked
D) ​bead
E) ​ball​

Question 79

Where the cold downdraft reaches the surface, the air spreads out horizontally in all directions. The surface boundary that separates the advancing cooler air from the surrounding warmer air is called a ____________________.​

Question 80

A sound occasionally mistaken for thunder is the ____________________.​