Storms 3 Flashcards by Ashley Wu

Difference between funnel cloud vs tornado

Funnel cloud before it touches ground
Tornado once it touches ground

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True or false: Shape is dependent on intensity classification

false, shape does not tell us about the intensity

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Do invisible tornadoes exist?

oui

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Most tornadoes are made visible by…?

cloud-water droplets (the funnel cloud)

and/or

dust and debris from the ground (debris cloud)

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What are some possible tornado shapes?

cone
V-shaped
wedge
cylinder
hourglass
rope

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Strong tornadoes are most likely associated with…?

supercell storms

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In North America, most Tstorms move from ___ to ___

SW towards NE

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what are tornadoes attached to?

Thunderstorms!

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True or false: only a small percentage of supercell Tstorms produce tornadoes

True: 20% - 30%

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How to recognize supercell rotation

Striations around mesocyclone
rotating wall cloud

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What is a funnel cloud

Water condensation funnel / cloud-water droplets
-> use this term before it touches ground

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What is a wall cloud

isolated lowering of cloud base beneath rain-free Tstorm base

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Where is the wall cloud

beneath rising cumulus towers
on SW flank of the storm
outside the precipitation region!

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Where do tornadoes come from, in a supercell storm?

they come from rotating wall clouds

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True or false: if we are in a car, we can easily drive away from most tornadoes

true, by taking a perpendicular path to the tornado path

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What are the translation speeds of the centre of a tornado?

Horizontal movement can be between
0 - 100 km/hr

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Are tangential speeds faster or slower than translation speeds?

i.e. rotational speeds, they are much faster!

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True or false: Translational winds causes the damage

False:
Tangential (rotational) winds cause the damage

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What is the Enhanced Fujita Scale? Where is it used?

Rates tornado intensity by amount of damage to buildings

EF0 (break windows) to EF5 (destroy buildings)
used in N. America

What is the TORRO scale? Where is it used?

Determined by wind speed

used in Europe

Describe the EF ratings

EF0
- trees snapped or toppled

EF1
- roof damage, windows broken

EF2
- roofs torn off, large trees snapped or uprooted

EF3
- destroyed homes, damage to large buildings

EF4
- homes are levelled, cars thrown a ways away

EF5
- completely levelled AND homes swept away, concrete structures badly damaged, trees completely debarked

Most tornadoes in Canada are ranked what EF scale?

EF0

How long do tornadoes normally last?

short lived, usually just minutes

Describe a tornado’s typical damage path

Narrow (width of house to size of city blocks)
paths often one to tens of km long

Tornadoes RARELY

- last for hours - have damage paths >1km wide, >100km long

In the case of a tornado, what are some safe places to be if you are indoors?

below ground (storm cellar or basement) get out of mobile homes!!

What is the worse place to be in a tornado

in a mobile home

In the case of a tornado, what are some safe places to be if you are outdoors?

get into a ditch place body below "line of fire" of moving debris

True or false: in a tornado, you could hide under highway bridges or overpasses

False: do NOT hide under highway bridge or overpass

What country do tornadoes occur the most?

North America 75%

Are tornadoes in Vancouver common?

Nope they are very rare

Where is Tornado Alley?

parts of Texas / OKC (east side of US)

Greatest tornado frequency in Canada

South Quebec / Ontario

Graupel is

small hail

What are tornado Outbreaks

6 tornadoes in one day and one region OR many tornadoes in a week

How often do outbreaks occur?

almost ever year in N America

Tornado outbreaks are often associated with____

Squall Lines

Squall lines often form along

cold fronts

As cold front moves towards SE, Tstorms move

toward NE

Describe the 5 stages of Tornado Evolution

1. Thunderstorm, dust whirl 2. Funnel cloud 3. Mature tornado 4. Decaying "rope" 5. Dissipating

True or False: Forecasting tornadoes is not difficult

False: forecasting tornadoes is very difficult

Tornado Watch

6 - 12 hr forecast Tells broad region where tornadoes are likely later in day - can continue with dailies but should monitor emergency news

Tornado Warning

Tornado actually detected NOW "Nowcast" warning tells - where tornado is / moving - warn specific towns in expected path - tornado sirens in towns are activated

What can detect tornadoes

Doppler radar -> sees vortex signature Human spotter

Tornado warnings come ___ prior to a tornado hitting

15 mins or less - must immediately take shelter