Transcript SEVERE WEATHER NOTES

SEVERE
WEATHER
NOTES
By Laura LeMay
What causes everyday
weather and storms?
•Air Pressure
•Air Masses
STORM:
• Violent disturbance in
atmosphere
• Caused by sudden change
in AIR PRESSURE
Angels enjoying HOT CHOCOLATE with lots of marshmallows!!!!!!
A. THUNDERSTORM
characteristics
• Heavy rain with thunder and lightning
• Form in large
CUMULONIMBUS CLOUDS
• form when WARM air is forced
upward at COLD front.
• Humid afternoons in
SPRING and SUMMER
2. WINDS
• Strong upward and downward
winds called
updrafts and downdrafts
• Downdrafts cause
WIND SHEAR
• Can exceed 160 km/hr
cumulonimbus
LIGHTNING
• Sudden spark of energy
• May heat air
as much as
30,000 C
http://physics-animations.com/Physics/English/ligh_txt.htm
Thunder
•Rapidly heated air
•EXPLOSIVE!!
•Travels slower than
lightning
Thunderstorm Video
• http://www.metacafe.com/watch/1393752/
awesome_thunderstorm/
How far is the storm
•
•
•
1) Count # between see lightning and hear
thunder
2) Divide that number by 3
FORMULA:
15 secs
3 s/km
a)9 secs
c) 3 secs
b) 21 secs
d) 30 secs
SAFETY
• Avoid metal (CONDUCTION)
• LIGHTNING RODS on large
buildings towers
• Get into LOW AREA away from
trees, poles…
• Get away from WATER
• In house avoid using
ELECTRICAL DEVICES
Lightning rod
Fast fact:
• The Empire State Building is designed to
serve as a lightning rod for the
surrounding area. It is struck by lightning
about 100 times per year.
7. FACTS:
• 16 million thunderstorms a year
• Every minute 100 bolts of lightning
strike Earth
• Kills 70 people/ year
• 300 + are injures
• Last 10 years started 15,000 fires
lightning
Sudden change in
pressure
Cold and hot
air masses
thunder
thunderstorms
Humid afternoons in
spring/summer (mostly)
Cumulonimbus Clouds
Updrafts and
downdrafts
of wind
B. TORNADO
• Rapid, whirling, funnel shape
cloud that reaches land.
• Over Lake/Ocean=
WATERSPOUT
Characteristics
• Brief but DEADLY
• (15 minutes or less)
• Winds may reach 480 km/hr
HOW FORM?
• Low, Heavy CUMULONIMBUS
clouds
• In SPRING and SUMMER
• usually in late AFTERNOON
• SQUALL LINES form where warm
and cold FRONTS meet.
4. TORNADO SAFETY:
• “WATCH” : tornados possible
• “WARNING: tornado has been spotted
Get in BASEMENT of well built building
MIDDLE OF GROUND FLOOR away
from WINDOWS AND DOORS
Lie under STURDY FURNITURE
GET OUT of mobile home and lie flat in
DITCH
Tornado Video
• http://video.nationalgeographic.com/video/
environment/environment-naturaldisasters/tornadoes/tornadoes-101/
5. Tornado Facts
• 800 occur per/ yr in the US
• “tornado alley” great plains
region-North Central Texas
across Oklahoma. Where
COLD air meets WARM air
High humidity
Spring and summer
afternoon
Squall lines
Cumulonimbus
clouds
tornado
Cold air
meets warm
air
Brief but
deadly
Spiral/funneling
winds
thunderstorms
C. Hurricane
•Tropical Storm with
winds 119 mph or
greater
1. Characteristics:
• Occur between JUNE and
NOVEMBER
• Typically 600 km across(300+ miles)
• Atlantic= HURRICANE
• In Pacific/Indian Ocean= TYPHOON
• Bring destruction/ but needed rainfall
to S and SE Asia
• May last 1 WEEK or longer
2. How FORMS:
• Begin over WARM water as LOW pressure
system. Begins as tropical depression
• Grows larger =
TROPICAL STORM
HURRICANE
• ENERGY comes from warm water/humid air
• Air RISES and produces clouds (called?)
• WINDS spiral in toward LOW pressure
• CENTER= low pressure and warm
temperatures
• Faster WINDS towards center
3. How Hurricanes Move:
• Carried by the TRADE winds
towards Caribbean and SE
United States
• FRICTION on land slows down
storm
4. Key Points:
• EYE= calm center of the storm with
ring of clouds surrounding
• Winds REVERSE in
OPPOSITE direction
after eye of the storm passes.
7. RANKING
5. DAMAGE
• Severe FLOODING
• WIND damage
• High waves
• STORM SURGE= most
dangerous part of storm (can raise
sea level 6 meters)
• “DOME” of water sweeps across
land
Hurricane Video!!
• http://video.nationalgeographic.com/video/
environment/environment-naturaldisasters/hurricanes/hurricane-montage/
6. SAFETY
• “WATCH”- possible within 36 hours=
prepare to leave
• “WARNING”- expected with 24
hours=
–EVACUATE
–If stay= board house/ stay in interior
8. HISTORY
• June 1972= AGNES- severe flooding in NC
to NY. 17 tornados in Florida and Georgia
• AUG 1992= ANDREW - $25 billion damage
– second-most-destructive hurricane in U.S.
history
• Aug 1999 = FLOYD=extensive flood damage
and coastal damage.
• AUG 2005 = Hurricane Katrina was the
costliest and one of the five deadliest
hurricanes in the history of the United States
PHOTOS:
Warm water
Rain/Major flooding
June to
November
tornadoes
Eye=calm
center
hurricane
Avg. 300
miles across
Low pressure system
May last weeks
High winds-reverse after eye
D. WINTER STORMS:
• Northeastern US high risk
• ROCHESTER and BUFFALO, NY get an average of
3 METERS/year
• LAKE-EFFECT Snows:
– Cold dry air
– Travels over
– Lake and
– Drops heavy
– Snowfall
– when
– cools
Lake Effect Video
• http://www.accuweather.com/en/weathervideo/lake-effect-snow/1261938918001
SAFETY:
• If in storm SEEK SHELTER
• Cover all exposed areas (remember:
WIND CHILL)
• STAY DRY
• Car: CLEAR EXHAUST (or CO poisoning)
Heavy snowfall
Blizzard/whiteouts
Winter storm
Convection/evaporation
/condensation
May cause
flooding in
spring melting
Winter season
/precipitation
Dry, cold air moves over warm, moist water=
lake effect snow
E. FLOODING
•Too much water
pours from
streams/rivers that
overflow banks and
cover land
surrounding
1. CHARACTERISTICS:
• Rain falls River rises land floods evacuate
• FLASH FLOOD: sudden, violent flood within
hours/minutes of storm
• May Cause MUDSLIDES/LANDSLIDES
Flood Video: Atlanta
• http://www.floodsmart.gov/floodsmart/page
s/videos/video_index.jsp
2. SAFETY
• “WATCH” –flooding possible, stay
alert
• “WARNING”- flooding reported, take action
1)move to HIGHER GROUND
away from WATER
2) Do not cross/play in STREAMS/DRAINS
3) Do not drive on FLOODED roads
4) BOIL water if possible
contamination
May occur in thunderstorms/tornados/hurricanes/winter
storms
flooding
Mudslides/landslides
Too much water
in a
short amount of
time= flash flood