It is estimated that at least 1,000 thunderstorms are in progress somewhere around the globe as we speak. Many of these storms will be harmless
in nature, but some will become severe, and unleash their fiery of destructive elements! The most violent breed of severe thunderstorms are known
as "Supercells". Supercells often unleash violent tornado outbreaks, or widespread "Derecho" events. Derecho is Spanish meaning straight
foreward. The most common elements of any "severe" thunderstorm are damaging straight-line winds of 58 mph or higher, large diameter hailstones of
at least 1 inch in diameter or larger, and of course, tornadoes. Other elements which are associated with severe storms are very heavy rainfall
which can result in dangerous flash floods, and vivid lightning displays. Knowing how to protect yourself from these storms is key to your own
Image at left shows thunderstorms as they appear from space. Taken from the International Space Station in 2016. Courtesy of NASA.
The most destructive element from a severe thunderstorm is known as a "tornado". By definition, a tornado is a violently rotating column of air in
the form of a funnel shaped pendent which extends from the base of a thunderstorm to the ground. It is not classified as a tornado unless the
funnel is on the ground! Tornadoes come in a variety of shapes and sizes, ranging from a thin rope-like funnel to a large wedge - often a mile or
more in width! The black or grey funnel may hop along and skip along the surface, and may appear as a single funnel, or as a group of tornadoes from
the same thunderstorm. The wind speed around a tornado vortex has never been accurately measured, but recent engineering studies from the damage left
by tornadoes seems to suggest the wind speeds could exceed 260 mph (EF5 rated tornado). Most tornadoes travel from the southwest to the northeast, but
have also traveled from northwest to southeast, at speeds ranging from stationary to 70 mph. A tornado which forms or moves over a body of water is
known as a "waterspout". Tornadoes of any magnitude can produce widespread destruction to property, and may even injure or kill people and animals in
their path. Theirfore, it's very important to take shelter quickly when a tornado is approaching your location!
Image at left courtesy of NOAA/NWS 2016.
Large hail in the form of odd shaped balls of ice which falls from a thunderstorm to the ground can be very destructive to crops and other outdoor
vegetation. It can also damage buildings, trees, and vehicles. Hailstones under 1 inch in diameter can still be damaging, but is not considered as
"severe" hail by definition. Hail can range in size from peas to audio CD's! Hail is formed inside the storm when updrafts of air carry a raindrop
higher into the storm where colder air freezes the raindrop into ice. This ice pellet then drops back down into the warmer air where another raindrop
forms on the ice pellet. Again, updrafts lift the ice pellet into the colder air where it refreezes. This process continues until the ice ball becomes
too heavy to stay inside the storm, so it falls to the ground as hail. The larger the hailstone, the more impact it will have. Remember, large hail
can injure you!
Image at left courtesy of NWS 1998.
DAMAGING THUNDERSTORM WINDS!
Severe thunderstorms can produce dangerous gusts of straight-line winds which often exceed 58 mph. These are known as "microbursts". Microburst winds
can produce heavy damage to trees, power lines, signs, water towers, buildings, and vehicles. If these winds become strong enough, they may develop into
a Derecho event, producing a more widespread area of destruction. Derechos are rare, but have occurred. The strongest known Derecho wind reported was 136
mph. When severe thunderstorms approach which cantains damaging winds, you should always take shelter.
Image at left courtesy of NOAA/NWS 2016.
YOUR SEVERE WEATHER SAFETY PLAN!
So, do you have a severe weather safety plan made? If you already have a plan in place, then you know what to do and where to go should severe weather
strike. But if you don't have a plan, then now is the time to create a plan. Before you create your plan though, you do need to do a few things.
One of those is to do a complete survey of where you live. Unless your well familiar with where you live, you need to know the general layout of the
building. This will help you to complete one part of your safety plan. Does your building have a basement for instance. Knowing what area of the building
is safest is the first part of your safety plan. Otherwise, my building does not have a basement, so where would the safest place be? The survey you do
will aid in finding this out. But now what if I live in a mobile home, where is the safest place to go? Unfortunately, for those of you who live in a
mobile home, there really is no safe place you can be. Even though the trailer may be tied down and well anchored, such units can be easily blown apart
by an F-2 rated tornado, or high winds. So if you live in a mobile home and you get word of a tornado warning, the best thing to do is evacuate it, and
head for a safer shelter area. The choices you make now, could mean the difference betwenn life or death.
Everyday people are forced to make many choices about things in their lives, and even choices they don't want to make. Many of those choices will likely be
wise ones, but others, not so wise. In fact, if a bad choice is made, it could be lethal! At the surface, many people would say and believe that it's wise
to have a smoke detector in your home. Why? The obvious answer is to alert you should a fire happen somewhere inside the building. After all, where their is
smoke there is fire! In fact many schools, hospitals and clinics even take this a step further by conducting monthly fire drills. Why? So that everyone knows
where to go and what actions to take if a fire broke out in the building. Now you may be asking, okay, but what does this have anything to do with severe
weather safety? By having a plan of action should a fire break out, everyone will know what to do, and where to meet. That same holds true for developing a
severe weather safety plan! So that everyone knows what to do, and where to go for safety. Think about it. Wouldn't it be a lot better to be safe then sorry?
So now you have a few more choices to make!
*Did you know that one bolt of lightning can reach a temperature of 50,000 F? It's true, and that's two times hotter then the
surface of the sun!
*Did you know that a tornado can sometimes be made up with several funnels at the same time? It's true, and such "extra" funnels
are referred to as "multiple vortices" which pivot around the primary funnel!
*Did you know that Derechos can cause widespread property damage, similiar to a tornado? It's true, but the damage pattern is more
straight forward, where a tornado's pattern is more circular.
*More fast facts coming soon!
SAFETY IS NO ACCIDENT! GET PREPARED NOW BEFORE IT'S TOO LATE!
Your survival during any severe weather event depends on one vital factor. PREPAREDNESS! There is no time like the present to start preparing for
what may happen at anytime. We cannot stress the term preparedness enough because it's so critical. Remember, the more prepared you are now, the safer you will
be when the event happens. The following are some general guidelines to help you create a severe weather safety plan:
Determine where the safest area is located where you live. In most homes and small office buildings, the basement would be your best option. Otherwise,
a suitable storm cellar is your next best option (rural locations). In homes and buildings without a basement or storm cellar, the lowest level is in order.
Get into any interior small room or hallway. A closet or bathroom is a good choice. Try to avoid rooms along the outside walls of the building!
For those who reside in pre manufactured homes (mobile homes), the only safe choice is to have a nearby shelter area you can get to on a moments notice.
Even though your home is well anchored and tied down, an F-2 rated tornado could easily destroy it in only seconds. This is why moblie homes are not safe
during a tornado or high winds.
When thunder roars head indoors! Severe thunderstorms don't need just tornadoes to injure or kill people. Their are other elements which can get the job
done just as easily. Those being damaging straight line winds, large hail, flash floods, and lightning. When a severe thunderstorm warning is issued for your
area, you need to cease all outdoor activities, and move indoors. Inside, stay clear and away from all windows and doors. Do not use any electrical items
during the storm i.e. radios, stereos, TV's, computers, hair driers, and the like. Likewise, don't use the telephone either during the storm. The lightning
may strike the line outside. Stay calm and know what the storm is doing. During the day, watch for signs of any wall cloud which may be rotating. If you see a
funnel cloud or tornado on the ground, take cover right away! Don't wait for a warning to come out!
Never be outside during a thunderstorm! If however, you are caught outside and no shelter is available, stay away from tall objects such as trees, power lines,
water towers, and bodies of water. Avoid being on hilltops or mountains. Try to get to a head-high clump of trees or brush. As an extreme last resort, crouch down
where you are in the open. Bend forward placing your hands on your knees. The idea is to remain as low of a target as possible.
Large hail and damaging straight-line winds of a severe thunderstorm are also dangerous. Damaging winds can cause tree and power line damage, as well as
damage to buildings and vehicles. Large hail can cause heavy crop damage, and also damage other outdoor vegetation. It can cause damage to vehicles and buildings.
These elements can inflict injury to people, and in some cases result in death. For these reasons, you need to be indoors when storms move through.
SOME TERMS OFTEN USED IN PREDICTING SEVERE WEATHER YOU SHOULD KNOW!
As part of severe weather safety, the National Weather Service (NWS) uses some terms that everyone should know and understand. Each of the following terms has
a different meaning, and that is also explained as well as any actions you should take in each situation. This is important for safety because you need to know
what kind of weather to expect, and what actions to take!
A few extra things to bear in mind....:
1). Although rare, on occasion conditions in the atmosphere may come together and trigger a more serious outbreak of either straight-line winds, or violent
tornadoes. These kind of events are known as Particularly Dangerous Situations or PDS for short. When PDS conditions are expected to occur, special
statements are issued by the National Weather Service to the public using every means available. Everyone in these areas should prepare immediately for the
rapid development and approach of any thunderstorms! Remember, Derecho events can often pack winds in excess of 120 mph! The stronger more violent tornadoes
can pack winds of 260 mph or greater! Either event can cause extreme damage to property, and result in injury or death. PDS situations should NOT be
WHAT IT MEANS ||
WHAT YOU SHOULD DO
SEVERE THUNDERSTORM WATCH
||Atmospheric conditions are favorable for severe thunderstorm development
in and close to the watch area over the next several hours.
||Continue with regular activity, but keep an eye to the sky every so often.
If you see cumulus clouds towering up into the atmosphere, this could indicate a developing storm.
Be ready to respond if a warning is issued. Remember, severe thunderstorms can and
generally do produce tornadoes, often with little or no advance warning!
SEVERE THUNDERSTORM WARNING
||Doppler radar has detected severe thunderstorms either within or about to enter
your county or parish.
||If you are outdoors, cease all activities and move inside your house or a
safe building at once. Indoors, stay away from all windows and doors. Don't use the telephone during
the storm unless it's an emergency. The lightning could strike the line outside. Make sure to unplug
all electrical items during the storm. Remain alert and informed.
||Atmospheric conditions are favorable for severe thunderstorms and tornadoes
in and close to the watch area over the next several hours.
||Continue with regular activity, but keep your eye on the sky occasionally
especially if you will be outdoors. If you observe cumulus clouds towering up into the atmosphere,
this could indicate a developing storm. Be ready to respond if a warning is issued.
||A thunderstorm capable of producing a tornado has been detected on Doppler radar,
or trained spotters have reported a confirmed tornado on the ground.
||If you live in the direct downstream location from the reported tornado, take
cover at once! Otherwise, remain fully alert and prepared to take cover if necessary since the storm
could produce additional tornadoes.
FLASH FLOOD WATCH
||Conditions are favorable for significant flash flooding over the next several
||If you live along or near to any river, creek, or small streams be alert and
watch for signs of rising water levels. If you observe flooding starting to occur, evacuate the area
at once. This also holds true for low lying areas which can flood easily.
FLASH FLOOD WARNING
||Flash flooding is imminent, or already occuring near your location.
||Evacuate the area immediately, and move to higher ground. Don't waste time
gathering clothes or food. Stay out of already flooded areas. Never attempt to cross a flooded
section of roadway! The water depth may be too great to allow for safe passage.
2). A common misconception amongst most people these days are that they actually feel less threatened during severe thunderstorm events as opposed to
tornado events. This stems apparently from the ideas that the storms will weaken and die out before reaching them, or change direction, and miss thei location
altogther. While it is possible these scenerios may happen, chances are good that if your area is put under a severe thunderstorm warning, such severe weather
is most likely to occur. You should never assume that a severe thunderstorm won't strike and therefore let down your gaurd. Always treat a severe
thunderstorm warning as seriously as a tornado warning.
3). The issuance of a severe thunderstorm watch does not preclude the occurance of tornadoes! In the vast majority of cases, tornadoes don't occur in
areas covered by a severe thunderstorm watch. However, in borderline cases, it becomes difficult for forecasters to fully determine whether or not tornadoes
may happen. It is for this reason people need to be aware that tornadoes could also occur during a severe thunderstorm watch period as well. In addition,
sometimes a watch can be issued for areas close to where you live, but your specific location is not included in the watch. Don't let this cause you to let
down your gaurd! If your area is close to the watch area, but not in the watch area, storms may still affect your area. Thunderstorms rarely ever follow a
straight line, or remain within man made boundaries created around them. So if your location is not "in" the watch area but close to it, you should also be
alert as well.
As previously mentioned above, the National Weather Service classifies a thunderstorm as "severe" if it contains one or more of the following:
When thunderstorms develop and then produce heavy to torrential rainfall over various locations, the ground may be unable to absorb all the water so quickly.
In most urban city areas, this excess water drains off into sewers and other drainage areas, while in rural locations, the excess water drains into nearby
rivers, creeks, and streams causing them to rise. If too much rainfall occurs, the sewers and other drainage areas, along with the rivers, creeks, and
streams begin to flood over, resulting in dangerous flash flood events. By definition though, a flash flood is a raging torrent of flood water which can
sweep up nearly everything in their path, including but not limited to trees, power lines, vehicles, boulders, and even whole buildings like houses. Some
people have driven their vehicles into flooded sections of roadway, and became stranded and trapped inside their vehicle. This is outright foolish because
the flood water could sweep you and your vehicle away, and you could loose your life. Here are some key things to remember:
||WINDS >= 58 MPH
The long and short of safety is knowing what to do in each instance, and having a thorough and complete knowledge of safety rules and related information .
This can go a long way toward your survival when such events occurs. The information provided on this page is intended for instructional purposes to help
educate the public about the dangers of severe thunderstorms, tornadoes, and flash floods. It is not intended as a complete guide to severe weather
safety. If you would like additional information, please contact our office through the contact page, or you can contact your local office of the National
VERY IMPORTANT! Midwest Weather Service is a small private establishment created for the sole purpose of severe
local storm prediction and forecast services for our clinets. We are in no way affiliate with, or have any ties with NOAA, it's National
Weather Service, or Storm Prediction Center. Our products are released for the coverage region we serve, and originate from, and are disseminated
by our Storm Center.
- If you live in low lying areas which are subject to sudden flooding, remain alert and
watch for signs of flooding starting to occur. If you are camping near any river or stream watch
for rising water levels.
- If you live near any rivers, creeks, or streams, keep a watch for signs of rising water
levels. If you see flooding starting to occur, evacuate the area at once! Don't wait for a warning
to get issued!
- If flooding is occuring, stay out of those locations. Select a route that will get you
to safer grounds. Do not go back to your home for clothing, food or other supplies.
- Never drive your vehicle through a flooded section of roadway! The water depth may be
too great to allow for safe passage. If you become stranded in your vehicle in a flooded section of
roadway, don't panic! Try to get out and move to a dry area if possible. Remember, flash flood
waters rise very quickly, and you could be engulfed in your vehicle.
- Be especially cautious at night when it's harder to recognize flood dangers.