Name:_________________
Tsunamis
Directions: Research these extreme weather conditions and answer the questions
below. Be thorough!!
1. How do Tsunamis Form?
2. Tsunamis are often no taller
than normal waves. Why are
they more dangerous?
3. Where do tsunamis typically
occur?
4. When and where did the
largest tsunami on record take
place?
A tsunami is a series of waves generated in an
ocean or other body of water by a disturbance
such as an earthquake, landslide, volcanic
eruption, or meteorite impact. Undersea
earthquakes, which typically occur at
boundaries between Earth's tectonic plates,
cause the water above to be moved up or down.
Because a tsunami wave is much longer than a
wind-driven wave and therefore carries a much
large volume of water and takes longer to pass.
While a regular ocean wave washes in and out
after a few seconds. A tsunami wave is a surge
of water that keeps coming in for up to 15
minutes. Because the wave lasts longer it goes
much further inland, sometimes as much as
several miles.
Tsunamis occur most often in the Pacific Ocean
and Indonesia because the Pacific Rim
bordering the Ocean has a large number of
active submarine earthquake zones (Pacific Ring
of Fire).
July 9, 1958 and Lituya Bay, Alaska
Tornadoes
What factors are necessary for a
tornado to form?
Describe the Fujita tornado
intensity scale.
Several conditions are required for the
development of tornadoes and the
thunderstorm clouds with which most
tornadoes are associated. Abundant low level
moisture is necessary to contribute to the
development of a thunderstorm, and a
"trigger" (perhaps a cold front or other low
level zone of converging winds) is needed to
lift the moist air aloft. Once the air begins to
rise and becomes saturated, it will continue
rising to great heights to produce a
thunderstorm cloud, if the atmosphere is
unstable. An unstable atmosphere is one
where the temperature decreases rapidly
with height. Atmospheric instability can also
occur when dry air overlays moist air near the
earth's surface. Finally, tornadoes usually
form in areas where winds at all levels of the
atmosphere are not only strong, but also turn
with height in a clockwise or veering
direction.
The Fujita Tornado Intensity Scale- Scale
that measures the intensity of a tornado.
F0 - Gale
With winds of less than 73 miles per hour
(116 kph), F0 tornadoes are called "gale
tornadoes" and cause some damage to
chimneys, damage sign boards, and break
branches off of trees and topple shallowrooted trees.
F1 - Moderate
With winds from 73 to 112 mph (117-180
kph), F1 tornadoes are called "moderate
tornadoes." They peel surfaces off of roofs,
push mobile homes off of their foundations
or even overturn them, and push cars off of
the road. F0 and F1 tornadoes are considered
weak; 74% of all measured tornadoes from
1950 to 1994 are weak.
F2 - Significant
With winds from 113-157 mph (181-253 kph),
F2 tornadoes are called "significant
tornadoes" and cause considerable damage.
They can tear the roofs off of light frame
houses, demolish mobile homes, overturn
railroad boxcars, uproot or snap large trees,
lift cars off the ground, and turn light
objects into missiles.
F3 - Severe
With winds from 158-206 mph (254-332
kph), F3 tornadoes are called "severe
tornadoes." They can tear the roofs and walls
off of well-constructed houses, uproot the
trees in a forest, overturn entire trains, and
can throw cars. F2 and F3 tornadoes are
considered strong and account for 25% of all
tornadoes measured from 1950 to 1994.
F4 - Devastating
With winds from 207-260 mph (333-416
kph), F4 tornadoes are called "devastating
tornadoes." They level well-constructed
houses, blow structures with weak
foundations some distances, and turn large
objects into missiles.
F5 - Incredible
With winds from 261-318 mph (417-509 kph),
F5 tornadoes are called "incredible
tornadoes." They lift and blow strong houses,
debark trees, cause car-sized objects to fly
through the air, and cause incredible damage
and phenomena to occur. F4 and F5 tornadoes
Where is tornado alley located?
What time of year do tornadoes
typically occur?
are called violent and account for a mere 1%
of all tornadoes measured from 1950 to 1994.
Very few F5 tornadoes occur.
F6 - Inconceivable
With winds above 318 mph (509 kph), F6
tornadoes are considered "inconceivable
tornadoes." No F6 has ever been recorded
and the wind speeds are very unlikely. It
would be difficult to measure such a tornado
as there would be no objects left to study.
Some continue to measure tornadoes up to
F12 and Mach 1 (the speed of sound) at 761.5
mph (1218.4 kph) but again, this a
hypothetical modification of the Fujita Scale.
Starts in central Texas and goes north
through Oklahoma, central Kansas and
Nebraska and eastern South Dakota
Late spring and earth summer. In the
southern states, peak tornado occurrence is
in March through May, while peak months in
northern states are during the summer.
Blizzards
What is a blizzard?
What are the weather conditions
like during a blizzard?
Blizzards are dangerous winter storms
that are a combination of blowing snow
and wind resulting in very low
visibilities.
A wind of 30 knots (56 kph / 35 mph) or
greater, sufficient snow in the air to reduce
visibility to less than 400 m (0.25 miles) for
an extended period of time (at least 3
hours), and low temperatures of minus
7C/20F or lower
The 1972 blizzard in Iran lasted
from February 3rd to 9th and
killed approximately 4000 people.
What is the record snowfall for a
In southern Iran, there was as
blizzard? Where and when was it? much as 28 feet (336 in) of snow.
Severe snow, low visibility, wind,
hypothermia
Name three dangers of blizzards.
Cyclones
What is a cyclone?
Differentiate between cyclones,
tornadoes, and hurricanes.
What is the Coriolis Effect?
A system of winds rotating inward to an
area of low atmospheric pressure, with
a counterclockwise (northern
hemisphere) or clockwise (southern
hemisphere) circulation; a depression.
A cyclone is any kind of circular
windstorm. Hurricanes form over water
and are huge, while tornados form over
land and are much smaller in size. A
tornado is a violent windstorm
characterized by a twisting, funnelshaped cloud.
Effect of a rotating body that
influences the motion of an object or
fluid; air moving north or south from
the equator appears to move right or
left.
Rotate in same direction as Earth
counterclockwise.
In which direction do cyclones spin.
Why?