Transcript Emma Gross group

Storms & Stuff
Emma Gross
Max Horwich
Rod O’Connor
Formation and Life-Cycle
Cumulus Stage:
• Masses of moisture are
pushed upward.
• Moisture condenses into
water droplets and becomes a
cumulus cloud.
• The heat released by the
condensation pushes the
cloud higher and creates a
low pressure zone underneath
the cloud.
Formation and Life-Cycle
Mature Stage:
• The warm air rises until it
hits air that is already
warm.
• Unable to rise further, it
spreads out and takes on
an anvil shape.
• Water droplets freeze to
ice particles, which fall
and melt on their way
down, creating rain.
• If the updraft is strong
enough, some droplets will
not melt all the way,
becoming hail.
Formation and Life-Cycle
Mature Stage (continued):
• Falling rain and hail create down
drafts. In combination with the
already present up-drafts, these
create turbulence within the
storm causing lighting, strong
winds, and occasionally
tornados.
• If there is little change in wind
speed or direction or wind sheer
the storm will “rain itself out”,
but if there is a lot of variance,
the storm may become a supercell.
Formation and Life-Cycle
Dissipation Stage:
• Updraft conditions cease
to exist.
• The storm is characterized
mostly by weak
downdrafts.
• Unable to sustain the
storm cycle, the storm
dissipates.
Types of Thunderstorms
Single Cell:
• Atmosphere
unstable, little or no
wind sheer,
precipitation cools
updraft.
• Storms short lived,
but can occur
several times in one
day.
Types of Thunderstorms
Squall Line:
• An organized line of multicell storms, usually preceded
by a gust front.
• Can be hundreds of miles long
and have very severe winds.
• Tend to form near mountain
ranges or linear weather
boundaries.
Types of Thunderstorms
Super-cell:
• Severe storms in which the
updraft has become
separated from the
downdraft, creating a strong,
rotating updraft called a
mesocyclone.
• Can reach miles into the air.
• Most likely type of
thunderstorm to produce
tornados.
Severe Thunderstorms
To classify as severe a storm must
have:
• Wind 57.5 mph or greater
• Hail 3/4 inch diameter or
greater
• Funnel clouds or tornados
• A storm which meets these
criteria may not always be very
dangerous, while some quite
dangerous storms fail to
classify as “severe”
Benefits
Rainfall & Flooding:
• In tropics and subtropics,
Almost all precipitation
comes from thunder storms.
• Rain from storms contains
particulate nutrients. Real
rain is better for plants than
artificially watering them.
• Floods due to storms deposit
nutrient rich sediment in
areas near rivers.
Benefits
Winds
• Winds clear forests of old and
dead trees and plants.
• Holes created in forest canopy,
enabling new young plants to
grow, and
• Storms keep the climate system
running properly, keep the
winters cool and summers warm.
Lightning
• Lightning converts air’s
nitrogen to a form usable by
plants, enabling them to
complete photosynthesis.
This nitrogen is called
“fixed” nitrogen.(Some
plants have bacteria that live
in their roots to do this.
• Lightning causes forest and
prairie fires which are apart
of a healthy ecosystem.
• Individual plants and
animals may suffer, but the
system as a whole benefits.
These fires create enable a
diversity of species to exist
in the various niches it
carves.
How humans deal with storms
Tornados:
• 70 fatalities and 1,500 injuries per year.
Straight-line Winds:
• Just as damaging as tornados.
• Extremely dangerous to aviation.
Lightning:
• 1318 deaths 1980-1995 (average 82 deaths
per year).
• 300 injuries per year. Mostly in Texas and
Florida.
• Odds of being struck by lightning: 1 in
700,000.
• Odds of being killed by lightning: <1 in 6
million.
Floods and precipitation
• Flash Floods
– 1,700 injuries, 140+ deaths per
year
– #1 cause of deaths associated with
thunderstorms
– Most fatalities occur at night and
most victims are people who
become trapped in cars
– Six inches of fast-moving water
can knock you off your feet; two
feet of water will cause most
vehicles to float
• Hail
– Four hailstorms in July 1996 and
1998 in Calgary, Alberta caused
total damages of $450,000+
– More than $1 billion in crop and
property damage each year
Solutions and Prevention
Shelters:
• 20,000-30,000 built since 1980
• Approx. 10,000 lives saved every year due to shelters and emergency
plans
• 36% of Americans do not have emergency preparedness plans
What to do after a storm:
• Listen to radio, TV, NOAA Weather Radio for updated information and
instruction
• Stay away from storm-damaged areas
• Watch out for fallen power lines and report them immediately
• Family Disaster Plan
• Gather information about hazards
• Learn what disasters can happen in your area
• Pick a meeting place in case you can’t return to your home