NORTH CAROLINA
SEVERE WEATHER AWARENESS WEEK
Feb 28th-March 6th, 2010

Severe Thunderstorms   Lightning    Tornadoes   
Flooding   Severe Weather Alert Process

 

Governor Bev Perdue in conjunction with the National Weather Service and Department of Crime Control and Public Safety have
declared this week as severe weather awareness week for 2010. All week long the national weather service will be issuing informative
messages to help you prepare for severe weather.

On Wednesday...March 3rd at 930 am...the National Weather Service will issue a statewide tornado drill in the form of a Required
Monthly Test on all NOAA weather radios. The alarm test will also be carried by local radio broadcasters. This will allow
schools...business...and residents the opportunity to practice their tornado drills and enact safety plans.

Given the recent active weather pattern this winter and chances for increased severe weather activity this spring...everyone across
North Carolina should use this week to think about what to do when threatened by lightning...hail...flooding...and tornadoes.
Thunderstorms bring a variety of threats...and knowing how to protect you and your family’s life is important.

Use this week to discuss safety with your children and students. Talk about where to take shelter and practice taking refuge in that
hall closet or bathroom. Setting aside a few moments this week to talk about severe weather safety with your family may one day save
your life and theirs

 

 

 

Severe Thunderstorms

...SEVERE THUNDERSTORMS...

For the first time since 1954 the National Weather Service has redefined the hail criteria for severe thunderstorms. The new hail
size criteria classifying a storm as severe is hail 1 inch in diameter hail or equal to the size of a quarter. For the last 55 years
hail three-quarters of an inch in diameter or penny sized was considered severe. This means severe thunderstorm warnings will no longer be issued
for hail the size of pennies and nickels. The wind criteria for a severe thunderstorms...58 mph or greater...remains unchanged.

Over the last five years there have been nearly 5000 reports of large hail and damaging wind statewide resulting in over thirty two
million dollars in damage. Severe thunderstorms are also responsible for injuries and even deaths in the state resulting from lightning,
high wind and tornadoes. The severe thunderstorm season in North Carolina typically starts in March and does not end until late
in the fall.

In 2009 warnings issued by National Weather Service offices provided An average of 19 minutes for severe wind and hail, with detection
rate of ninety percent. It is worth noting that the National Weather Service does not issue warnings for lightning and given the deadly
nature of lightning you should always be aware of the lightning danger anytime a thunderstorm is nearby. A good rule of thumb to
live by is when thunder roars go indoors.


...LARGE HAIL...

In the last 5 years severe thunderstorms in North Carolina have produced hail as large as tennis balls and even baseballs across
northwest North Carolina. While hail is not usually life threatening, these large chunks of ice cause serious damage to
roofs, automobiles, and crops. Hail season in North Carolina typically runs from mid March through early July, typically peaking
in May.

Hailstones grow in thunderstorms with strong updrafts. These strong upward moving currents of air keep the ice suspended inside the
thunderstorm...allowing the chunks of ice or hailstones to grow larger and larger. Once the hail become too heavy for the updrafts
to keep suspended...they fall to earth as hail.

...DAMAGING WIND…

Severe gusts of wind from a thunderstorm called downbursts or straight line wind are a serious danger. Nationally over the last 30
years nearly as many people have been killed by straight winds as from tornadoes. Thunderstorm gusts rush down from the storms
sometimes reaching speeds in excess of 100 mph. Thunderstorm wind of this magnitude impact large areas creating widespread damage and
injuries. Damaging straight line winds can cause damage equivalent to that of a tornado.

Lines of well organized thunderstorms...called squall lines...occasionally move across North Carolina in the
spring and early summer. These dangerous storm systems can be very explosive racing across the state at over 50 mph creating widespread
wind damage over entire counties.

Damaging wind events in North Carolina typically start as early as mid march and run into august. Damaging thunderstorm wind
events are most notable from may through early August which is much longer than the typical severe hail season.


...SAFETY...
You can protect yourself during thunderstorms by remembering this phrase…hide from the wind and lightning. Stay away from windows when storms approach and seek shelter in an interior bathroom or closet when the wind really starts to blow.

Your best line of defense against severe thunderstorms...is to stay informed. There are so many great outdoor activities across the state of North Carolina and severe weather can bring a quick end to a days pleasure. Listen to NOAA all-hazards weather radio, television or local
radio for the latest forecasts and possible threat of thunderstorms and severe weather. If warnings are issued...take action and protect your family and property. Remember being safe is a lot better than being sorry.

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Lightning

Lightning occurs with all thunderstorms and is what defines a thunderstorm. Northwestern North Carolina faces dangers from lightning throughout the entire spring and summer. Over the course of one year, the earth will be struck by lightning nearly 20 million times. In a typical year there are around 500,000 lightning strikes in North Carolina. Since 1959 there have been nearly 200 reported lightning deaths in North Carolina. Unfortunately many lightning deaths go unreported and are attributed to cardiac arrest meaning the actual number of lightning deaths in North Carolina is probably much higher. Most lightning deaths are the result of cardiac arrest so knowing how to respond quickly using c.p.r. can save a lighting victims life.

Lightning results from the buildup and discharge of electrical energy between positively and negatively charged particles. A thunderstorm builds up a huge electrical charge as ice particles inside the storm collide and through friction generate a static charge. These particles of suspended ice in the thunderstorm collide as they are carried around by the storm’ updraft and downdraft. Once the electrical charge is strong enough to travel from the cloud to the ground, a lightning bolt is created.

A lightning bolt carries as much as 300000 amperes and one billion volts. The air around the lightning strike is instantly heated to 50,000 degrees.
This is five times hotter than the surface of the sun. This instantaneous heating of air around the lightning strike causes the air molecules to explosively expand. This expansion occurs so rapidly it compresses the air forming a shock wave similar to a sonic boom. The shock wave travels through the atmosphere...resulting in thunder. The acoustic shockwave near the lightning strike is strong enough to rupture the eardrums of those
standing nearby.

You can use thunder to gage the distance of a lightning strike. You merely count the number of seconds between the moment you see the flash of lightning and hear the clap of thunder. Once you see lightning...start counting seconds. For every 5 seconds that go by before you hear the clap of thunder...that’s one mile. Keep in mind this technique only tells you how far away that one lightning strike was from your location. The next one could be a lot closer. Lightning can travel as far as 10 to 12 miles from a thunderstorm. For that reason, anytime you hear thunder or see lightning, seek shelter indoors.

Most lightning fatalities occur when people are caught outside working or taking part in some recreational activity. Because of the abundance of outdoor activities in North Carolina...we are especially vulnerable to lightning. If outside...move indoors if possible. Stay off of the telephone and stay away from windows. If caught outdoors, stay away from trees, telephone poles, and other tall objects. When boating...try to seek safe shelter before the storm approaches. Stay indoors for at least 30 minutes after hearing the last clap of thunder. This should guarantee your safety.

More information about lightning can be found by visiting: http://www.lightningsafety.noaa.gov

http://www.srh.noaa.gov/srh/jetstream/lightning/lightning_intro.htm

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Tornadoes

Tornados are one of nature’s most violent phenomena. Tornado season typically starts in Spring in the months of March…April and May. Tornadoes have touched down in the state in all months with the largest number of tornado related fatalities occurring in March. Other months with the highest numbers of tornado related fatalities include April…May and November.

Just last year...a number of tornadic thunderstorms struck the state resulting in as many as 8 strong to violent tornadoes rated on the
Enhanced Fujita scale as EF-2 and higher with winds in excess of 130 mph. One such tornado occured in Alleghany County on May 8th.
These tornadoes injured dozens of people...leaving families homeless and resulted in over 3 million dollars in damages. A number
of tornadoes struck at night as everyone slept catching many individuals off guard despite warning lead times averaging 20
minutes. These night time monsters have a history of being particularly deadly in North Carolina.

...Tornado Dangers...
A study of tornadoes found that North Carolina was ranked first in The nation with the greatest percentage of people killed by night
time tornadoes. Of all the tornado fatalities since 1950, eighty-two percent of tornado fatalities in North Carolina have occurred at
night. Compare this with the fact that only about twenty-eight percent of all tornadoes actually touch down at night. A potential
reason for the is high fatality rates in comparison to high-risk areas like tornado alley could be the prevalence of night time
tornadoes in March, May and November. The stronger tornadoes tend to strike during these three months.

Tornadoes are difficult to visually identify at night by both the public and trained spotters. Even when warnings are provided at
night, people sleep at home are less likely to hear those warnings. In addition, residents have a tendency to be in more
vulnerable housing and building structures (e.g., mobile or manufactured and single family homes) during the night in comparison
to safer locations (e.g., school or place of work in steel or reinforced-concrete buildings) during the day. Whether at home or
work remember when proper planning and action come together lives are saved.

...Tornado Safety...
Most tornado deaths and injuries across the state have occurred outdoors...in automobiles...and mobile homes. When a tornado warning
is issued for your area or if you spot a tornado...seek shelter in a substantial building. The safest place is in an interior bathroom or
closet. Put as many walls between you and the outside as possible. Stay away from windows as debris picked up by a tornado can easily
shatter a window and enter your house. If you are caught outdoors...seek shelter in a low spot like a ditch
or culvert. You want to get as low as possible to protect yourself from all of the flying debris in a tornado. The debris within the
tornado is what causes nearly all of the injuries and deaths. If in your car and threatened by a tornado...abandon your vehicle and seek
shelter in a substantial structure or in a ditch. Never try to outrun a tornado in a vehicle. Tornadoes do not travel in straight
lines and it can be very difficult to determine what direction the tornado is moving.

Also never seek shelter from a tornado under an overpass. There is no safe place under and overpass. In fact seeking shelter under an
overpass puts you more at risk from violent winds and flying debris. The National Weather Service will issue tornado watches when
conditions are favorable for thunderstorms to produce tornadoes. Once a tornado is spotted or detected by radar...the National
Weather Service will issue a tornado warning. Any time a tornado warning is issued for your area...take action to protect your life
as well as the lives of your family.

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Flooding

Flood related deaths are a serious nationwide problem. Nationwide...flooding causes more fatalities than any other type of severe weather. Several factors contribute to flooding. The two main factors are the intensity of rainfall and how long rain occurs over any given location.
Urbanization...topography...soil type and soil moisture also play roles in the severity of flood conditions.

Flooding in North Carolina can result from several different weather situations. Slow moving thunderstorms can repeatedly move over the
same location resulting in rapid flash flooding...or days of steady rain can cause creeks and rivers to flood over large areas. Lastly,
any thunderstorm moving across metropolitan or urbanized areas can cause flash flooding due to the amount of runoff generated by
highly developed areas.

Rushing water in the form of a flash flood can quickly become deadly. Just a few inches of fast-moving flood water can knock you
off of your feet while just one to two feet of moving water can overtake a car forcing it off the road. The combination of the
force of flowing water and buoyancy floating a vehicle make driving into flood waters extremely dangerous. Just one and a half to two
feet of water will float most cars and wash them away downstream. Most flood deaths occur in automobiles. When approaching water
flowing over the road, turn around and go the other way. Don’t Drown...turn around.

Knowing your area's flood risk at home and work is also very important. Check your homeowner's or renter's insurance. Many
policies do not cover flooding and many areas across North Carolina are subject to flooding although not officially declared within a
flood plain. Just because flood damage is not in your insurance policy does not mean your house cannot flood.

Before rain and flood waters threaten...evaluate your flood risk and know where you will go if you need to evacuate. Many times your
escape route can flood before your house as roads nearby experience flooding. Also realize...just because areas around your home have
never flooded before does not mean you will never experience a flood.

When flooding is possible...the National Weather Service will issue a Flood Watch. This tells you to remain alert to the possibility of
heavy rain and flooding. Once a flash flood warning is issued...then it is time to take action. When a warning is issued for your area...
it means that flooding has been reported or is imminent. This is the time to closely monitor the situation and move quickly if flood
waters threaten.

If advised to evacuate, do so immediately. Move to a safe location before access is cut off by flood waters. Never allow children to
play around high water...creeks...streams or storm drains.

When heavy rain and flooding threatens your area, stay informed by listening to NOAA weather radio, local television and radio.

For more information about flooding, visit the flood safety web site.

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Severe Weather Alert Process


The Blacksburg National Weather Service along with emergency management officials...the American Red Cross...and local media all work together preparing communities for the next natural disaster. The mission of the National Weather Service is to protect the life and property.
However it is how you prepare for and respond to severe weather which really saves lives. Make sure that you know what to do once
a warning is issued and the alarm is sounded. Understanding the difference between a watch and warning is an important factor in
understanding how to react and protect yourself.

Severe weather watches:

When widespread severe weather is possible across North Carolina, the National Weather Service will issue a watch. Watches are issued
for tornadoes...severe thunderstorms and floods. A watch provides you a heads up alerting you that severe weather is expected in the
near future. As storms develop...they could become life threatening and damaging. Watches are intended to raise situational awareness
and allow you time to prepare.

When a Watch is issued remain alert to approaching storms. Watches are transmitted via NOAA weather radio as well as local television
stations.

Severe weather warning:

When severe weather is imminent or already occurring...the National Weather Service will issue a warning! Warnings indicate an immediate
threat to property some times even life. When warnings are issued you should have a high awareness of the danger and enact your safety
plan if threatened.

When warnings are issued for your area...you should stay away from Windows and seek shelter in the middle of your home on the lowest
Floor as storms threaten. All warnings should be taken seriously. If You are caught outside or are a boater on the water, you are
Especially at risk. Be sure that you know how to protect yourself.

Warnings are transmitted via NOAA weather radio as well as by local television stations. Local television stations are the front lines
for dissemination of National Weather Service warnings. Most residents in North Carolina receive warning information from the
National Weather Service through local television and radio. Today’s technology also allows you to receive many types of weather alerts
over wireless devices such as cell phones. Such services are provided by many companies in the public and private sector.

Before the storm:

Preparing before the storm is the most important. Have a NOAA weather radio with a warning alarm tone and battery backup in your
home. A weather radio will alert you to the threat of severe weather in your county day or night.

Develop a safety plan and share it with your entire family. Schools should have a written plan in place and practice that plan at least
twice a year.

Staying informed about severe weather and making sure that you know what to do when severe weather threatens will keep you and your
family safe. The actions you take just moments before a tornado or severe thunderstorm hits can save your life.

You can prepare for severe weather and disasters by planning ahead, creating a disaster supply kit...and learning the safest places to
seek shelter when at home...work...school...or outdoors. You should take time to understand basic weather terms and the danger signs
related to severe weather and know how to respond. Severe weather can strike in an instant. Your chances of staying safe are greater if you have a plan and practice your plan. When individuals and communities prepare for disasters...lives are saved.

NOAA weather radio:

NOAA weather radio is a nationwide network of radio stations broadcasting continuous weather information directly from the
nearest National Weather Service office. NOAA weather radio broadcasts official weather service warnings...watches...forecasts and
other hazard information 24 hours a day...7 days a week. Known as the "voice of NOAA's National Weather Service..." NOAA weather radio is
provided as a public service. In North Carolina nearly 30 NOAA weather radio broadcast stations provide weather forecast and
warning information for all 100 counties. No matter where you live there is a NOAA weather radio station nearby.

NOAA weather radio will alert you 24 hours a day to the following weather hazards in your county: tornadoes...severe thunderstorms...
flash floods...river floods and winter storms. Broadcasts are found in the VHF public service band on these seven frequencies ranging from
162.400 MHz to 162.550 mhz. These special receivers range in price from $20 to $65...through most radios cost less than $40.
The weather radios round-the-clock protection can be a life-saving investment and they can be found in most electronic stores and on
many popular. When purchasing a NOAA weather radio Consumers are recommended to buy a radio with the S.A.M.E. (Specific
Area Message Encoded) technology. The S.A.M.E. technology allows the User to program specific counties into the radio such that it only
Receives alerts for the desired county or counties. This greatly Reduces the number of alerts received.

For residents to be as safe as possible, NOAA weather radio needs to become as common in homes...schools...businesses and public places as
smoke detectors.

Please visit the NOAA weather radio site for more details


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