Severe
Weather and Tornadoes Tips
The season for severe
thunderstorms begins in the spring and lasts through hurricane
season. Thunderstorms develop in warm moist air in advance of
eastward-moving cold fronts. Tornadoes in the
winter and early spring are often associated with strong, frontal
systems that form in the Central States and move east.
Tornadoes can form in hurricanes therefore the threat along the
Virginia coast last until hurricane season ends the end of November.
A tornado on the
York River or the Chesapeake Bay is called a waterspout. Sometimes they
move on shore and
cause damage and injuries.
Click
to see waterspout off Florida Keys. Photographed from aircraft
Photo
Date: September 10, 1969
Dr
Joseph Golden, NOAA
NOAA
CENTRAL LIBRARY, Historical National Weather Service Collection
TORNADO
FACTS for EMERGENCY ACTIONS
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Tornadoes
come in various shapes, sizes, and strength. |
Weak
tornadoes (winds less than 110 mph) represent 69% of all tornadoes
and cause less than 5%of deaths.
Strong
tornadoes (winds 110 - 205 mph) represent 29% of all tornadoes and
cause 30% of all tornado deaths.
Violent
Tornadoes (winds greater than 205 mph) represent 2% of all
tornadoes and cause 70% of all tornado deaths.
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No
place is safe from tornadoes including areas near rivers, lakes,
and mountains. Opening windows to equalize pressure and minimize
damage has NO effect on a structure. Instead go to an
internal, first floor safe area in the structure or to
basement. |
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Tornadoes
occur at any time of the year. |
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Tornadoes
typically occur in the southern states, March through May and in the
northern states during the summer months. |
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The
hours between 3 and 9 p.m. appears to be the peak time for tornadoes,
but they can occur at any time during the day. |
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Usually
tornadoes move from southwest to northeast at an average speed of
30 mph. Yet, there can be variations in direction and
speed. Some have been identified with a forward motion
of 70 mph. |
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Who's
most at risk: |
People
in automobiles
Elderly,
very young, and the physically or cognitively impaired.
People
in mobile homes
People
who may not understand the warning due to a language barrier.
LISTEN
and LOOK
During
periods of severe weather listen to a radio or even better use a NOAA
weather radio for special weather messages. Weather terms that
everyone needs to be familiar with include:
Tornado
Watch: Tornadoes are possible in your area. Remain
alert for approaching storms.
Tornado
Warning: A tornado has been sighted or indicated by
weather radar. If a tornado warning is issued for your area and
the sky becomes threatening, move to your pre-designated place of
safety.
Severe
Thunderstorm Watch: Severe thunderstorms are possible in
your area.
Severe
Thunderstorm Warning: Severe thunderstorms are occurring.
During
periods of severe weather, mother nature can provide some of the
following warning signals that life-threatening weather is
approaching:
Dark greenish
sky
Wall
cloud
Large
hail
A
loud roar, similar to a freight
train.
Often
and especially in this part of the country, tornadoes develop without
much warning. It is important to monitor the weather and be
observant for environmental signals of impending danger. Don't
second guess the weather, take cover to be safe.
Safety
Actions
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Pre-designate
a safe area on the first floor or basement of your home.
First floor internal spaces away from windows and exterior doors,
such as closets, bathrooms, or areas under a stairwell. Get
into the kneeling position Cover the back of
the head and neck. |
If
your in a bathroom, get into the tub and assume the same
position. If possible drag a mattress to cover yourself.
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When
caught in other buildings, get to the first floor and look for the
nearest bathroom or go to basement. Sometimes, safe areas are
marked. Stay away from windows and external doors. |
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When
you see those environmental warning signals and a funnel cloud, leave your
car immediately and drop into a ditch away from traffic, if possible. Don't try
to outrun a tornado in a car. |
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A
mobile home even when tied down should be abandoned for a close-by sturdy
structure or a ditch. |
Graphics
and information
in italics is quoted from the National Weather Service web site at www.nssl.noaa.gov/NWSTornado/
For more details on tornadoes please visit this site.
Other
emergency preparedness information links
York
County's Office of Emergency Management
LIGHTNING SAFETY
Virginia
Department of Emergency Management
Federal
Emergency Management Agency
F
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