Transcript File - Mrs. DiLorenzo Earth Science

Storms and Severe
Weather
• Storm: violent disturbance of the atmosphere that
creates dangerous conditions on Earth’s surface.
• Can cause loss of life, injuries, and loss of property.
• Types of storms:
– 1.
– 2.
– 3.
– 4.
– 5.
– 6.
– 7.
Mid-Latitude Cyclone
• Created by the movement of air masses along the
polar front of the middle latitudes.
• Storms form when a warm air mass is lifted and
begins rotating as a low-pressure cyclone.
Rain will fall
in front of the
warm front
and right on
top of the
cold front.
Hurricanes
• Hurricanes are extremely low pressure systems that form
over tropical ocean waters.
• Gain energy from the condensation of millions of gallons
of water vapor from evaporation of water.
• Winds greater
than 74 mph
• Greatest danger:
storm surge in
coastal areas
Hurricane Safety
• Biggest dangers during a hurricane:
– High winds
– Flooding
– Storm Surge
• During a hurricane:
–
–
–
–
Evacuate low-lying areas
Board up windows
Stay indoors
Stock up on food supplies, water,
batteries, gasoline, $$
Storm Surge
Saffir-Simpson Scale
Thunderstorms
• Thunderstorms are heavy rainstorms accompanied
by thunder and lightening.
• Form by:
– The uplifting of warm air associated with fronts;
– As part of hurricanes, or
– When local heating causes warm, moist air to rise.
DEVELOPING STAGE
A towering, puffy
cloud
indicates rising air.
MATURE STAGE
Hail, heavy rain,
lightning, strong winds,
tornadoes.
DISSIPATING STAGE
Rainfall decreases,
strong downdrafts.
• Cloud changes to
• 10 – 20 minutes
water vapor after a
few hours.
Thunderstorm Safety
• Biggest dangers during a thunderstorm:
– Flooding, hail, high winds, lightening
• During a thunderstorm:
– Don’t be the highest object in an area
– Don’t stand under a tree
– Stay inside (don’t touch electrical devices or anything
attached to a buildings plumbing)
Tornadoes
• A tornado is a rapidly
rotating, extremely lowpressure funnel that hangs
down from thunderstorm
clouds.
– Usually very narrow
– Usually last a few minutes
• Form at front between air
masses with big differences in
temp, and t-storm clouds
Super-outbreak
of tornadoes on
April 3-4, 1974.
148 tornadoes in
24 hours
Tornado Safety
• Biggest dangers during a tornado:
– Flying debris / extremely strong
winds
• During a tornado:
– Get into a basement or
underground shelter
– If no basement, get into interior
room or hallway
– Get under a sturdy piece of
furniture
– Stay away from windows
– Get out of automobiles or mobile
homes
The Fujita Scale
Blizzard
• A blizzard is a storm with winds of 35mph + and
includes large amounts of snow
Blizzard of
Dec 2010
Blizzard Safety
• Biggest dangers during a blizzard:
– Drifting snow can shut down transportation, electrical
service, and prevent people from obtaining food and
fuel.
– Outdoors: Frostbite, hypothermia, freezing to death
• During a blizzard:
– Stay indoors
– Stock up on food and other supplies