Upgrade to remove ads
Terms in this set (24)
"a violently rotating column of air, pendant (hanging) from a cumuliform cloud or underneath a cumuliform cloud, and often (but not always) visible as a funnel cloud. A damaging circulation is on the ground.
which are rotating thunderstorms with a well-defined radar circulation called a mesocyclone. can also produce damaging hail, severe non-tornadic winds, unusually
frequent lightning, and flash floods
dictated mainly by things which happen on the storm scale, in and around the mesocyclone.
tornado development is related to temperature changes across the edge of downdraft air wrapping around the mesocyclone
a tornado over water--usually meaning non-supercell tornadoes over water. Common along the
southeast U. S. coast--especially off southern Florida and the Keys--and can happen over seas, bays and lakes worldwide. They don't officially count in tornado records unless they hit land. They are smaller and
weaker than the most intense Great Plains tornadoes, but still can be quite dangerous. Can also overturn boats, damage larger ships, do significant damage when hitting land, and kill people.
How are tornadoes in the northern hemisphere different from tornadoes in the southern hemisphere?
The sense of rotation is usually the opposite. Most tornadoes (but not all!) rotate cyclonically, which is counterclockwise in the northern hemisphere and clockwise south of the equator. Anticyclonic tornadoes (clockwise-spinning in the northern hemisphere) have been
observed, however--usually in the form of waterspouts. "cyclonic" tornadoes spin counter-clockwise in the northern hemisphere, and clockwise in the southern
How long does a tornado last?
Can last from several seconds to more than an hour. Most tornadoes last less than 10 minutes.
rotates, but has no ground contact or debris, and is not doing damage. Some are high-based and
may never reach the surface.
What direction do tornadoes come from?
Can appear from any direction. Most move from southwest to northeast, or west to east. Some have changed direction amid path, or even backtracked. [A tornado can double back suddenly, for example, when its bottom is hit by outflow winds from a thunderstorm's core.]
How do tornadoes dissipate?
Need a source of instability (heat, moisture, etc.) and a larger scale property of rotation (vorticity) to keep going.
the flow of wind out of the precipitation area of a
shower or thunderstorm. Many tornadoes have been observed to go away soon after being hit. Some kinds of thunderstorm outflow may help to cause tornadoes, while other forms of outflow may kill tornadoes.
What is the purpose of a tornado?
the most efficient way to move air from one part of the
atmosphere to another on its size and time scale. Transporting a plume of initially unstable air from the lower
atmosphere to higher levels
fluid flow (gas or liquid)
a vortex often forms when some kind of instability
difference exists between one part of the fluid and another, and that difference is strong enough that the fluid needs to move quickly to restore more stable conditions again.
How is tornado damage rated?
The F-scale developed by Dr. T. Theodore Fujita. . In Britain,
there is a scale similar to the original F-scale but with more divisions. The wind speeds are based on calculations of the Beaufort wind scale and have never been scientifically verified in real tornadoes. Enhanced F-scale winds are derived from engineering guidelines but
still are only judgmental estimates because:
1. Nobody knows the "true" wind speeds at ground level in most tornadoes, and
2. The amount of wind needed to do similar-looking damage can vary greatly, even from block to block or building to building,
Damage rating is (at best) an exercise in educated guessing.
a much more precise and robust way to assess tornado damage than the original. It classifies F0-F5
damage as calibrated by engineers and meteorologists across 28 different types of damage indicators (mainly various kinds of buildings, but also a few other structures as well as trees). The idea is that a "one size fits all" approach just doesn't work in rating tornado damage. Needs to take into account the typical strengths and weaknesses of different types of construction.
determine amount of damage and
the appropriate structure.
The intersection is the initial
estimate - then add or subtract
the first column number.
That depends on what it is hitting, its size, intensity, closeness and other factors. The most common tornado sound is a continuous rumble, like a nearby train. Sometimes a tornado produces a loud whooshing sound, similar to a waterfall, or the noise of open car
windows while driving very fast. Tornadoes which are tearing through densely populated areas may be producing all kinds of loud noises at once, which collectively may make a tremendous roar.
What's the nature of tornadoes in hurricanes and tropical storms?
Hurricane-spawned tornadoes tend to occur in small, low-topped supercells within the outer bands, NNW through ESE of the center--mainly the northeast quadrant. Occasionally a tornado will happen in the
inner bands as well, but the large majority still form outside the hurricane force wind zone.
How do you forecast tornadoes?
look for the development of temperature and wind
flow patterns in the atmosphere which can cause enough moisture, instability, lift, and wind shear for tornadic thunderstorms. Find out the location, strength and movement of the fronts, drylines, outflows, and other boundaries between air masses which tend to provide lift. Figure out the moisture and temperatures, both near ground and aloft, which will help storms form and stay alive in this situation. Find the wind structures in the atmosphere which can make a thunderstorm rotate
Dopplerradar signatures can tell warning meteorologists a great deal about a thunderstorm's structure, but usually can't see the tornado itself.
What is a tornado watch?
defines an area shaped like a parallelogram, where tornadoes and other kinds of severe weather are possible in the next several hours. It does not mean tornadoes are imminent, just that you need to be alert, and to be prepared to go to safe shelter if tornadoes do happen or a warning is issued.
means that a tornado has been spotted, or that Doppler radar indicates a thunderstorm circulation which can
spawn a tornado.
a safe room
reinforced small rooms built in the interior of a home, which are fortified by concrete and/or steel to offer
extra protection against tornadoes, hurricanes and other severe windstorms. They can be built in a basement, or if no basement is available, on the ground floor. In existing homes, interior bathrooms or closets can be fortified into "safe rooms." \
the peak period for historical tornado reports in an area, when averaged over the history of reports. There
is a general northward shift from late winter through mid summer.
This set is often in folders with...
FDSCI 201 EXAM 2 Part 1 (Volcanoes)
FDSCI 201 Case Studies
Volcanoes and Landslide Unit
Midterm: Mass Wasting
You might also like...
tornadoes + hurricanes
Severe and Unusual Weather Test #3
Weather - Tornadoes
Other sets by this creator
State Literacy Test
LIT 1 Final Exam
Manner and Placement of Sounds
Other Quizlet sets
Government Quiz 1-5
WOH CH. 6 #1-66