Lightning Safety

Document Sample
Lightning Safety Powered By Docstoc
					Oklahoma Dept of Corrections | Staff & Organizational Development




                Lightning Safety
Course Information
• Data source: National Oceanic & Atmospheric
  Administration (NOAA), U.S. Dept. of Commerce.
  Website: http://www.noaa.gov

• Photography: All photos, including title background, are
  courtesy of NOAA.


• Course design: Lynne Presley, Oklahoma Dept. of
  Corrections, Staff and Organizational Development Unit,
  lynne.presley@doc.state.ok.us


• Course published October 12, 2005. Oracle SAFI39000.

• Course credit: One hour (assuming all links are followed).
Course Objectives
 At the end of this course, students will be able to:

 1.   Understand the different ways that cloud to ground
      lightning can kill people.

 2.   Name at least 2 physical injuries that a lightning bolt
      can cause.

 3.   Calculate a storm's distance by using the "Flash to
      Bang" method.

 4.   Understand indoors and outdoors safety precautions to
      avoid being struck by lightning.
Introduction
Did you know that lightning is the second-leading weather killer in
the U.S.? (Floods are number one.) Lightning is more deadly than
tornadoes or hurricanes. According to the NOAA, lightning strikes in
the U.S. kill over 70 people and injure hundreds more each year.
According to the NOAA:
• Approximately 25 million cloud to ground lightning strikes occur in
the U.S. each year.
• The air within a lightning strike can reach 50,000 degrees
Fahrenheit.
• Lightning can heat its path five times hotter than the surface of the
sun
• One ground lightning strike can generate between 100 million and
1 billion volts of electricity.
How Lightning is Formed
Lightning is caused by the attraction between
positive and negative charges in the
atmosphere, resulting in the buildup and
discharge of electrical energy. This rapid
heating and cooling of the air produces the        ++
shock wave that results in thunder. During a
storm, raindrops can acquire extra electrons,
which are negatively charged. These surplus
electrons seek out a positive charge from the
ground. As they flow from the clouds, they
knock other electrons free, creating a
conductive path. This path follows a zigzag
shape that jumps between randomly distributed
clumps of charged particles in the air. When the
two charges connect, current surges through
that jagged path, creating the lightning bolt.
(NOAA)
How Lightning is Formed, cont'd.
Lightning flashes don't always strike the ground. They can
occur within a cloud, or from cloud to cloud.




                                               NOAA
Lightning Damage
Cloud to ground lightning can
injure and kill people in different
ways. For instance, lightning
can strike and hit a person
directly. Lightning can also
branch off to a person from
another object, such as a tree,
pole, or other tall object. Also,
lightning may travel through
power and phone lines and
plumbing pipes to a person who
is in contact with an electric
appliance, telephone, or
plumbing fixture.
                                      Lightning striking the Eiffel Tower,
                                      June 3, 1902, at 9:20 P.M. NOAA
Lightning Damage, cont'd.




   These cows were killed when lightning struck the fence,
   and the current traveled along the fence killing the cows.
   Photo: NOAA/Ruth Lyon-Bateman
  Physical Injuries
Lightning strikes can produce a variety of physical injuries and
disabilities, including:
• Cardiac arrest
• Brain damage and nervous system injuries
• Pain and bodily damage from being thrown by the strike
• Impaired thinking and mental confusion
• Burns
• Death
On average, 20% of lightning strike victims die, and 70% suffer
serious long-term effects.
Lightning Warning Signs
High winds, rainfall, and a             How Long Can a
darkening cloud cover are the          Lightning Bolt Be?
warning signs for possible
                                Recent research from Vaisala-
cloud-to-ground lightning
                                GAI's LDAR and LDAR II lightning
strikes.                        detection networks show that
Things to remember:             lightning can travel 60 miles or
                                more. The longest bolt they have
• If you can hear thunder,      seen to date was 118 miles long
lightning is close enough to    in the Dallas-Ft. Worth, Texas
strike your location.           area. Since 3-D lightning
                                measurements are relatively new,
• Lightning can strike miles    however, scientists are learning
away from any rainfall.         more every day and these
Lightning can also travel       numbers may change.
sideways for many miles. If     Source: National Severe Storms
you hear thunder, look for      Laboratory, NOAA
cover.
Storm Proximity
It's not uncommon to see a flash of lightning, then hear the thunder
some seconds later. It's possible to estimate how close the storm is
by using the "Flash to Bang" method. According to NOAA, it's very
simple:
1.Once you see a lightning flash, start counting the seconds until
you hear the thunder.
2. Divide the number of seconds by 5 to get the distance in miles.
Example:
If thunder is heard:             The lightning is:
10 seconds after a flash         2 miles away

                10 seconds divided by 5 = 2 miles

  Remember: If the time between a lightning flash and the sound of
  thunder is 30 seconds or less, seek shelter immediately!
Safety Precautions - Inside
There is no way to guarantee that you won't be hit by lightning.
However, taking safety precautions can reduce the risk.
A house or substantial building offers the best protection from
lightning. Why? Because they have pipes and wires going into the
earth, which grounds the structures. Be sure to follow these safety
tips from NOAA while in a house or building during the
thunderstorm:
• Avoid contact with corded telephones, electrical equipment, and
cords.
• Avoid contact with plumbing. Do not wash your hands, do laundry,
wash dishes, or take a shower or bath.
• Stay away from windows, doors, and porches.
• Do not lie on concrete floors, and do not lean against concrete
walls (the concrete may contain wire mesh, which can conduct
electricity).
Safety Precautions – Outdoors

 Remember that NO OUSIDE LOCATION IS SAFE DURING A
 THUNDERSTORM! However, if you are outdoors when a
 thunderstorm occurs, and you can't find shelter in a building,
 follow these NOAA safety guidelines to avoid the most
 hazardous locations:
 • Stay away from partially-open outdoor shelters, such as car
 ports, picnic shelters, tents, open garages, and covered patios.
 • Some vehicles are safer than others. Safer vehicles include
 those with hard tops. Unsafe vehicles include convertibles, golf
 carts, motorcycles, bicycles, boats, and other vehicles with soft
 or no tops.
Learn More About It




  Many people believe that a vehicle's rubber tires protect
  them from being hit by lightning, so it doesn't matter if
  the vehicle has a top or not. Untrue! Actually, the metal
  frame and roof of a vehicle provide protection by
  diverting the electrical current away from the people
  inside. This is why vehicles with soft tops and
  convertibles are less safe than vehicles with metal tops –
  the current can't be diverted along the top.
Safety Precautions – Outdoors
   There are other precautions
   you can take if you are
   outdoors when a
   thunderstorm occurs, and you
   can't find shelter in a building:
   • Do NOT seek shelter under
   tall isolated trees or poles.
   Lightning typically strikes the
   tallest object.
   • Stay away from metal
   objects such as fences, wires
   and poles.
                                       This isolated pole is a
                                       magnet for lightning!
Warning Signs
 People sometimes receive a few seconds of warning
 before being struck by lightning. For instance, the
 following events have been reported:
 • Hair standing up
 • Tingling skin
 • Light metal objects start to vibrate
 • Seeing a corona discharge (electrical spark)
 • Hearing a crackling sound
 If you experience any of these warning signs, and
 cannot seek inside shelter, assume the position shown
 on the next slide.
Safety Precautions – Outdoors
   If lightning is in the immediate area, and there is no safe
   location nearby, get into the "lightning crouch" position.
   Crouch down, but DO NOT lay down. Bend your knees
   down while keeping your feet together. (NOAA)


 NOTE: If you're with
 a group, everyone
 should spread out
 so there are several
 body lengths
 between each
 person. Once
 spread out, assume
 the position shown
 in the picture to the
 right.
                          The "Lightning Crouch" position. NOAA
First Aid
 Being struck by lightning doesn't
 mean automatic death. People
 who are struck by lightning don't
 carry a charge – it's safe to touch
 them and provide medical
 treatment. Call 911 immediately,
 and conduct a basic first-aid
 assessment, focusing on breathing
 and pulse. Begin CPR as
 necessary while you wait for
 medical assistance to arrive.
 (NOAA)
Course Review



  “Self-Test”
Course Review: Question 1of 10



  1. The air within a lightning strike can reach
  50,000 degrees Fahrenheit.


                                                Click here
                                                for correct
                                                  answer
      Answer: True




                                         Click here for next question
Course Review: Question 2 of 10



  2. Rapid heating and cooling of air during a storm
  produces a shock wave that results in _________.


                                               Click here
                                               for correct
 Answer: Thunder                                 answer




                                        Click here for next question
Course Review: Question 3 of 10



  3. Lightning flashes always strike the ground.



                                               Click here
                                               for correct
 Answer: False. Lightning can                    answer
 also flash within a cloud, and from
 cloud to cloud.


                                        Click here for next question
Course Review: Question 4 of 10



  4. Lightning can hit a tree, then travel to a person.



                                                 Click here
                                                 for correct
 Answer: True                                      answer




                                          Click here for next question
Course Review: Question 5 of 10



  5. Being hit by lightning "jolts" the brain and
  improves brain function.


                                                  Click here
                                                  for correct
 Answer: False. Being hit by                        answer
 lightning can cause brain damage,
 impaired thinking, and mental
 confusion.

                                           Click here for next question
Course Review: Question 6 of 10


  6. High winds, __________, and a darkening
  cloud cover are warning signs of a possible cloud
  to ground lightning strike.

                                              Click here
                                              for correct
 Answer: Rainfall                               answer




                                       Click here for next question
Course Review: Question 7 of 10

  7. The "Flash to Bang" method helps to identify
  how close a storm is. Use the method to solve
  this problem: If thunder is heard 5 seconds after a
  lightning flash is observed, how far away is the
  storm?

                                                       Click here
                                                       for correct
Answer: 1 mile.                                          answer

To calculate the distance, remember this
formula:
# of seconds divided by 5 = distance in miles

                                                Click here for next question
Course Review: Question 8 of 10


 8. Taking an indoors shower or bath during a
 thunderstorm does not increase a person's
 chance of being struck by lightning.


                                                   Click here
Answer: False. Remember that electrical            for correct
current can travel through plumbing pipes            answer
and hit you.




                                            Click here for next question
Course Review: Question 9 of 10


 9. Why does a house or other substantial building
 offer protection from being struck by lightning?



                                                    Click here
Answer: Because most houses and                     for correct
buildings have pipes and wires going into             answer
the earth, which "grounds" them and
guides electrical currents into the earth.



                                             Click here for next question
Course Review: Question 10 of 10


 10. It's a good idea to seek shelter during a
 thunderstorm under the tallest tree you can find.



                                              Click here
Answer: False. Lightning typically strikes    for correct
the tallest object in an area.                  answer
Learn More About It
 Want to learn more about lightning storms?
 Visit these sites:

 http://www.noaa.com/lightning.html
 The National Oceanic & Atmospheric Administration's
 "Lightning" web site.


 http://www.nssl.noaa.gov/researchitems/lightning.shtml
 The National Severe Storms Laboratory's "Lightning" web site.
Conclusion

Obviously, we want to avoid being struck by
lightning. We can improve our chances by
following the safety precautions in this course.

Stay alert, and stay safe!

				
DOCUMENT INFO
Shared By:
Categories:
Tags:
Stats:
views:11
posted:9/11/2012
language:Unknown
pages:31