The document discusses severe weather safety, defining watches and warnings for tornadoes, severe thunderstorms, and lightning. It provides guidance on what to do during different types of severe weather, including seeking shelter in an interior room on the lowest floor if a tornado warning is issued and avoiding open areas or isolated structures during lightning. The document also aims to dispel common myths about severe weather.

1. SEVERE
WEATHER
SAFETY

2. BACKGROUND
Between 04 April and 22 June 2011, over 800 tornadoes were
reported across the Midwest, southeast, and Ohio Valley. These
storms killed over 500 people and caused more than 27 Billion
dollars in damages. Source NOAA.gov

3. Severe Weather Safety
AGENDA:
 Severe weather definitions
 What to do in the event of a tornado
Tornado myths and facts
 Lightning myths and facts
Summary

4. Severe Thunderstorm Watch & Warning
A National Weather Service (NWS) Severe Thunderstorm Watch is defined as:
This is issued by the National Weather Service when conditions are favorable for the
development of severe thunderstorms in and close to the watch area. The size of the
watch can vary depending on the weather situation. They are usually issued for a
duration of 4 to 8 hours. They are normally issued well in advance of the actual
occurrence of severe weather.
A National Weather Service (NWS) Severe Thunderstorm Warning is defined as:
This is issued when either a severe thunderstorm is indicated by radar or a spotter
reports a thunderstorm producing hail one inch or larger in diameter and/or winds equal
or exceed 58 miles an hour; therefore, people in the affected area should seek safe
shelter immediately. Severe thunderstorms can produce tornadoes with little or no
advance warning.

5. Tornado Watch & Warning
A National Weather Service (NWS) Tornado Watch is defined as:
This is issued by the National Weather Service when conditions are favorable for the
development of tornadoes in and close to the watch area. Their size can vary depending
on the weather situation. They are usually issued for a duration of 4 to 8 hours. They
normally are issued well in advance of the actual occurrence of severe weather. During
the watch, people should review tornado safety rules and be prepared to move a place
of safety if threatening weather approaches.
A National Weather Service (NWS) Tornado Warning is defined as:
This is issued when a tornado is indicated by radar or sighted by spotters; therefore,
people in the affected area should seek safe shelter immediately. They can be issued
without a Tornado Watch being already in effect. They are usually issued for a duration
of around 30 minutes.

6. NWS “Particularly Dangerous Situation”
A National Weather Service (NWS) “Particularly Dangerous Situation”is defined
as:
A PDS is a term used to describe a 'Particularly Dangerous Situation' arising from the
issue of a severe weather watch or warning. The addition of a PDS watch means there
may be some very large hail, severe winds, intense lightning, or other severe weather
dangers. Typically a PDS watch is rare. Forecasters issuing a PDS must feel there is an
imminent threat to life or property. Tornadoes are expected to be either intense, or long-
lived. Aka potentially dangerous situation

7. WHAT TO DO IF A TORNADO
WARNING IS ISSUED
Source NOAA.gov
 Have a plan in place
 Know where you will go when at home or at work.
 Don’t wait until the last minute to go to your storm shelter.
 In a house with no basement, a dorm, or an apartment
 Avoid windows. Go to the lowest floor, small center room (bathroom or closet), under a
stairwell, or interior hallway.
 Crouch as low as possible facing down and cover your head with your hands.
 Get into a bathtub if possible
 Cover yourself with padding (blankets or mattress) to protect from debris.
 In a mobile home
 Get out! Even if your home is tied down, it is not as safe as an underground shelter or
permanent, sturdy building. Evacuate to a permanent structure.
 In a car or truck
 If the tornado is visible and far away and traffic allows, drive out of the area.
 Seek shelter underground or in a sturdy shelter if possible.
 If no flying debris and OBVIOUSLY lower ground is available, leave your car and lie face
down covering your head with your hands.

8. Tornado Myths/Facts (Slide 1)
1. “When traveling by car seek shelter under an overpass."
FALSE: The number one priority in tornado safety right now is to discourage people
from seeking shelter under overpasses. Wind Currents are concentrated as they are
squeeze under the overpasses and are increased in speed. This increase in speed with
flying debris INCREASES the risk of injury or death.
2. “Mobile homes attract tornadoes."
FALSE: Mobile homes are not more likely to be hit, it just seems that way. There are
tens of thousands of mobile homes spread across tornado alley. Mobile homes offer little
to no protection against even the weakest tornadoes, so when a tornado does strike a
mobile park, the damage is more likely to be significant.
3. “Hills / Rivers / Cities deflect or inhibit tornadoes."
FALSE: Tornadoes have been observered crossing the Appalachian Mountains, 30
significant tornadoes have crossed the Mississippi river, and major tornadoes have
plowed right through Dallas, Kansas City, Omaha, ect. In August 1999 a tornado went
right through downtown Salt Lake City. In fact, an urban tornado will have a lot more
debris to toss around than a rural twister.

9. Tornado Myths/Facts (Slide 2)
4. “We should open windows if a tornado is approaching."
FALSE: STAY AWAY from all windows. It won’t make any difference whether the
windows are open or closed IF your home is struck by a tornado. Getting everyone to a
place of safety should be your only priority.
5. “The southwest corner of the house is the safest location during a tornado."
FALSE: Always go to the lowest level and center of the house as far as possible from
exterior walls and windows during a warning and cover youself.
6. “Deaths from tornadoes are more likely in the Southeastern U.S. than in the Great
Plains."
TRUE: Partly due to: Population concentration, lack of basements, time of day, and a
higher concentration of mobile homes.

10. Tornado Myths/Facts (Slide 3)
7. “There are small U.S. regions of unexpected high tornado frequency and areas with
unexpected low frequency of tornadoes."
TRUE: There are several “holes” in the map of tornado distributions and small regions of
extreme concentration. Hall County has a tornado density of 124.5 tornadoes per 1000
sq. miles. However, Lancaster County only has 35.8 tornadoes per 1000 sq. miles and
Dodge County only has 35.5 tornadoes per 10,000 sq. miles.
8. “Tornadoes, like lightning never strike twice."
FALSE: Guy, Arkansas has been hit 3 times by a tornado damaging the same church
each time. Cordell, KS had a tornado hit it on May 20th >>> 3 years in a row! –
1916,1917, & 1918.
9. “Tornadoes are the number one weather killer in the U.S."
FALSE: 1960-1996 total fatalities: for Flash Floods: 4629; Lightning: 3221; Tornadoes
2734; Hurricanes 1104.

11. Tornado Myths/Facts (Slide 4)
10. “The “clash of the seasons” causes tornadoes."
FALSE: A temperature contrast is important, but circulation dynamics (shear), upper
level support (jet stream), and high moisture content are more important than a
temperature contrast.
11. “Reported tornadoes are increasing in frequency."
TRUE: but, is it real? It is assumed that since the number of days with tornadoes is NOT
increasing nor are the larger tornadoes increasing in number, just the smaller ones, that
the increase might be the result of better reporting of the smaller tornadoes (more
reported than previously).
12. “Annual tornado deaths are decreasing in number."
FALSE: Early on – in the data record – it was true, but during the last decade the fatality
rate has leveled off and stopped decreasing. But, when taking into account the
increasing population, while the rate remains static, overall it is actually becoming safer.

12. Tornado Myths/Facts (Slide 5)
13. “Tornadoes can rotate clockwise as well as anti-clockwise."
TRUE: A few small F-0 and F-1 tornadoes can rotate “anti-cyclonically” (especially late
summer, NW flow tornadoes). Also, though rare, small tornadoes can change (morph)
from anti-cyclonic to cyclonic.
14. “Most tornadoes are the large size that you see on the evening news."
FALSE: Most tornadoes are small 50-100 feet wide, travel less than 1 mile, and last just
a few minutes. The large F-4 and F-5 tornadoes combined represent less than 5% of all
tornadoes.
15. "Tornado damage is caused by rapid reduction in pressure. (You should leave
windows open as a tornado approaches."
FALSE: Damage is caused by wind gusts and flying debris. Don’t worry about equalizing
the pressure, the roof ripping off and a pickup truck smashing through any wall will
equalize the pressure for you. Dr. Ted Fujita showed that an open garage causes MORE
damage to a house.

13. Tornado Myths/Facts (Slide 6)
16. “Tornadic thunderstorms produce an above average amount of lightning and a larger
than normal amount of hail compared to non-tornadic thunderstorms."
TRUE: Intense updrafts amplify charge separation and electrical build-up as well as
increased lifting to freeze layers of super cooled water drops.
17. “Doppler radar will observe ALL tornadoes."
FALSE: Doppler radar, although much more accurate than earlier radar, cannot see the
very smallest of tornadoes that are “rope-like” in size. Plus, due to the curvature of the
earth, Doppler radar can only see the upper portions of storms that are more than 60
miles away from the radar.
18. “The movie “TWISTER” with Helen Hunt and Bill Paxton was based on the National
Severe Storms Laboratory and University of Oklahoma storm chasers and was
therefore, very factual."
FALSE: Hollywood produces fantasy For reality, check out the many documentaries
shown by the Weather Channel, Discovery Channel, and the IMAX movie: “STORM
CHASERS”.

14. Tornado Myths/Facts (Slide 7)
19. “Tornado chasing looks like its fun. Should I try it."
FALSE: It may look like fun, but it is extremely dangerous. Leave the chasing to the
professionals and watch their photographs from the safety of your home.
20. “Tornadoes have picked people and items up, carried them some distance and then
set them down without injury or damage."
FACT: People and animals have been transported up to a quarter mile or more without
serious injury. Fragile items, such as sets of fine china, or glass-ware have been blown
from houses and recovered, miles away, without any damage. However, given the
quantity of airborne debris, these occurrences are the exception, rather than the norm.
21. “Cars are safer than mobile homes during a tornado (with no other shelter
available)."
TRUE-FALSE-MAYBE: BOTH are DEADLY locations, but cars might be marginally
safer according to researchers. However, the best advice is to abandon both for shelter.

15. Tornado Myths/Facts (Slide 8)
22. "I can outrun a tornado, especially in a vehicle."
FALSE: Tornadoes can move at up to 70 mph or more and shift directions erratically
and without warning. It is unwise to try to outrace a tornado. It is better to abandon your
vehicle and seek shelter immediately.
23. “A tornado is not coming directly at me, I am safe."
FALSE: Tornadoes have been known to act erratically, often suddenly changing
direction very quickly. Sturdy shelter is the only safe place to be during a tornado.

16. Lightning Myths/Facts
“Lightning never strikes the same place twice.”
MYTH: Lightning often strikes the same place repeatedly, especially if it’s a tall, pointy,
isolated object. The Empire State Building is hit nearly 100 times a year.
“If it’s not raining or there aren’t clouds overhead, you’re safe from lightning.”
MYTH: Lightning often strikes more than three miles from the center of the
thunderstorm, far outside the rain or thunderstorm cloud. “Bolts from the blue” can strike
10-15 miles from the thunderstorm.
“If you are in a house, you are 100% safe from lightning.”
FACT: A house is a safe place to be during a thunderstorm as long as you avoid
anything that conducts electricity. This means staying off corded phones, electrical
appliances, wires, TV cables, computers, plumbing, metal doors and windows. Windows
are hazardous for two reasons: wind generated during a thunderstorm can blow objects
into the window, breaking it and causing glass to shatter and second, in older homes, in
rare instances, lightning can come in cracks in the sides of windows.

17. Lightning Myths/Facts Continued
"If outside in a thunderstorm, you should seek shelter under a tree to
stay dry.”
MYTH: Being underneath a tree is the second leading cause of lightning casualties.
Better to get wet than fried!
“Structures with metal, or metal on the body (jewelry, cell phones,Mp3 players, watches,
etc), attract lightning.”
MYTH: Height, pointy shape, and isolation are the dominant factors controlling where a
lightning bolt will strike. The presence of metal makes absolutely no difference on where
lightning strikes. Mountains are made of stone but get struck by lightning many times a
year. When lightning threatens, take proper protective action immediately by seeking a
safe shelter & don’t waste time removing metal. While metal does not attract lightning, it
does conduct it so stay away from metal fences, railing, bleachers, etc.

18. SUMMARY
 Know the difference between a watch and a warning
 Know where you’ll go
 Flying debris is the greatest danger in High Wind Conditions
 Have a NOAA weather radio that will wake you up at night
 Not all tornadoes will have a warning issued before they hit