Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Natural Hazards > Tornadoes > Flashcards

Tornadoes Flashcards

1
Q

What are tornadoes

A

Short lived, very intense, localised storms.

Violently rotating columns of air descending (sometimes to ground level) from a thunderstorm cloud.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Why are tornadoes often visible

A

Due to dust and debris suck up

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is a wedge tornado

A

Wide base - 100k across

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is a rope tornado

A

Thin air localised tornado. Small diameter

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What are waterspouts

A

Tornadoes over water are called waterspouts

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Example of waterspout

A

Gerona, Spain. 6 people killed when the waterspout collapsed onto the pier

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

How do tornadoes form

A

Vortex produced when strong winds bringing cold dry air pass over warm moist rising air. Two different air masses moving in different directions, rolling motions where they interact with each other. Strong updraft - gearing of the ground, evaporation so rolling air mass gets lifted up vertically into tornado

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Where are tornadoes often spawned

A

By thunderstorms and hurricanes as they travel inland

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is the structure of a tornadigenic thunderstorm

A

Overshooting top.
Anvil shape thunderstorm cloud.
Outflows.
Mesocyclone - strong updraft, below you tend to get tornadoes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is the overshooting top of a tornado

A

Above the troposphere in the stratosphere it is the area directly above the area of strong updraft. Pushing cloud top up higher

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Where do tornadoes occur

A

Tornado alley (central USA) suffers the most numerous and devastating tornadoes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

How many tornadoes per year in tornado alley

A

1000 causing 100 deaths

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Which states are in tornado alley

A 
Texas
Oklahoma
Kansas
Colorado
Nebraska
S.Dakota
Iowa
Minnesota
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Why is tornado alley a thing

A

Low level winds bring warm moist air from the South East (gulf of Mexico), and high level winds bring cool dry air from the west (Rocky Mountains)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Example of tornadoes in the uk

A

Tay bridge train disaster, 1879, caused by a waterspout in Scotland. 75 killed.
Birmingham tornado, 2005, wedge shape.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What are the features of a typical tornado

A

Diameter - 250m.
Pressure at centre - 10% lower than surroundings.
Path length - 25km.
Forward speed - 45km/h.
Duration - 15 minutes.
Spin anti-clockwise in Northern Hemisphere.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Can you out drive a tornado

A

If the conditions are good

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Can you get multiple tornadoes formed by the same thunderstorm

A

Yes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is used to analyse tornado strength

A

Enhanced Fujita Tornado Damage Scale (EF0-EF5)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What is the tornado strength a relationship between

A

Wild speed and destructiveness

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What is the strength of most tornadoes

A

Weak so EF0-EF1. Only 2% are EF4 or EF5

22
Q

What percentage of deaths are EF4 or EF5 caused

23
Q

What are wind speed based on

A

Degrees of damage of vegetation and building.on 3 second gusts, not continuous wind speed but still causes damage

24
Q

What is damage to buildings caused by

A

The force of the wind itself.

Flying debris and objects such as cars.

25
How many categories are in the tornado damage
6
26
How is damage localised
Total obliteration of one street while the next street is unscathed
27
In the USA what is the most vulnerable area
Mobile homes
28
Example of a record holding tornado
``` The tri-state tornado 1925 and outside the peak season for tornadoes. 3.5 hours. 700 killed. 15,000 homes destroyed. 350km path. 1.5km widest oaths ```
29
What is the peak season for tornadoes
June to October bc sea surface temperature have risen enough to feed positive feedback loop
30
How to reduce vulnerability
Long term preparedness.
31
What is the long term preparedness for reducing vulnerability
Difficult to design tornado proof buildings. Construct concrete/ underground shelters. Educate vulnerable communities.
32
What do they educate
How to spot when a tornado is coming and how to use a shelter
33
Example of w tornado warning system
Operated by NOAA since 1953 in the USA
34
How does the tornado warning system work
Forecast tornadigenic weather conditions like mesocyclone. Issue a tornado watch alert and intensify monitoring. Try to detect tornadoes. Issue a tornado warning. Initiate emergency plans.
35
How to detect tornadoes
Radar station, spotter networks and satellite images
36
Where should you take refuge in a tornado
Underground is best. Indoors, away from Windows, is next best. If outdoors, lying in a ditch is best (beware flooding). Evacuate vehicles.
37
What is a spotter network
Look for characteristic cloud formations e.g mammatus clouds often presage US tornadoes
38
Warning signs of tornados
``` Dark greenish/black sky. Large hailstones falling. Clouds moving very fast, especially in a rotating pattern or converging toward one area of the sky. Rushing/ roaring sound. Debris dropping from sky (animals too). ```
39
How to use satelittles to detect tornadoes
Visible - look for shadow cast by overshooting top of thunderstorm cloud. Infrared - thunderstorm clouds tend to be cooler (higher in atmosphere) than other clouds. Moisture - look for adjacent moist (white) and dry (black) air masses
40
What is infrared
Temperature information and colour enhanced
41
What is the structure of a tornadigenic thunderstorm
``` Overshooting top (top of updraft) in stratosphere. Rotating updraft. Flanking line (new storms forming) Rain shaft. Storm movements ```
42
Thing to detect tornados
Doppler radar
43
Info on the Doppler radar
155 fixed DR stations in USA. Since 1990s. Mobile stations enhance coverage. Emits pulse of radio waves and measure the wavelength (or frequency) and intensity of pulse reflected from raindrops.
44
What does the Doppler radar provide info on
Size, location, storm speed, wind speed and rainfall intensity
45
How does the Doppler radar work
Radar sweeps and beems of radio waves going out. Estimate how big from time taken to go out and come back tells us how far they travelled and the size, speed and winds of the storm. If it was stationary then the radio waves would have the same wave length as one that’s being beamed out but if it’s moving towards a system it has shorter radio waves but if it’s moving away then it would have longer wave lengths than they were on the way out.
46
What do hook shapes indicate
Mesocyclonic rotation. Red is more intense and moving away from the station
47
What does reflectivity show
Rainfall intensity
48
What does velocity show
Direction of air movement. Green is air moving inbound towards the radar. Red is air moving outbound away from the radar.
49
Why can’t tornadoes be detected by radar
They are too small
50
What do meteorologists look for
Adjacent red (outbound) and green (inbound) areas in a larger thunderstorm. Indicates rotation which may spawn tornadoes
51
Limitations of using the Doppler radar
Detection more likely and earlier (around 15-30 mins before tornado forms). But false alarms and undetected tornadoes are quite common. Not all tornados are associated with mesocyclones. Can’t detect circulations that are too close, too far or blocked from views

Natural Hazards (7 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions