Emergency Management:
Spring and summer weather
Tornadoes
Emergency statistics
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The best protection during a tornado is an interior room on the lowest level of a building,
preferably a basement or storm cellar.
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Tornadoes strike with incredible velocity. Wind speeds may approach 300 miles per hour,
travel distances over 100 miles and reach heights over 60,000 feet above ground. These
winds can uproot trees and structures, and turn harmless objects into deadly missiles, all
in a matter of seconds. Mobile homes are particularly vulnerable to tornadoes.
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Injuries or deaths related to tornadoes most often occur when buildings collapse, people
are hit by flying objects or are caught trying to escape the tornado in a car.
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Tornadoes are most destructive when they touch ground. Normally a tornado will stay on the
ground for no more than 20 minutes; however, one tornado can touch ground several times in
different areas.
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Tornado season is generally March through August, although tornadoes can occur at any time
of the year. They tend to occur in the afternoons and evenings: over 80 percent of all
tornadoes strike between noon and midnight.
Preparing for a tornado
When a tornado is coming, you have only a short amount of time to make life-or-death decisions.
Advance planning and quick response are the keys to surviving a tornado.
Designate an area in your home as a shelter and practice having everyone in the family go there
in response to a tornado threat. Discuss with family members the difference between a "tornado watch" and a "tornado warning".
Have the following disaster supplies on hand:
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Flashlight and extra batteries.
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Portable, battery-operated radio and extra batteries.
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First aid kit and manual.
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Emergency food and water.
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Non-electric can opener.
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Essential medicines.
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Cash and credit cards.
Develop an emergency communication plan
In case family members are separated from one another during a tornado (a real possibility
during the day when adults are at work and children are at school), have a plan for getting
together.
Ask an out-of-state relative or friend to serve as the family contact. After a disaster, it's
often easier to call long distance. Make sure everyone in the family know the name, address and
phone number of the contact person.
Tornado watches and warnings
A tornado watch is issued by the National Weather Service when tornadoes are
possible in your area. Remain alert for approaching storms. This is the time to remind family
members where the safest places within your home are located, and listen to the radio or
television for further developments.
A tornado warning is issued when 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. Turn on a battery-operated radio and wait for
further instructions.
When the sirens sound to notify you of bad weather conditions please tune into a local
broadcast channel.
PLEASE DO NOT CALL 911.
Mobile homes
Mobile homes are particularly vulnerable. A mobile home can overturn very easily even if
precautions have been taken to tie down the unit. When a tornado warning is issued, take
shelter in a building with a strong foundations. If shelter is not available, lie in a ditch or
low-lying area a safe distance away from the unit.
Tornado danger signs
Look out for:
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Dark, often greenish sky.
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Wall cloud.
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Large hail.
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Loud roar, similar to a freight train.
Caution:
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Some tornadoes appear as a visible funnel extending only partially to the ground. Look for
signs of debris below the visible funnel.
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Some tornadoes are clearly visible, while others are obscured by rain or nearby low-hanging
clouds.
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Before a tornado hits, the wind may die down and the air may become very still.
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An approaching cloud of debris can mark the location of a tornado even if a funnel is not
visible.
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Tornadoes generally occur near the trailing edge of a thunderstorm. It is not uncommon to
see clear, sunlit skies behind a tornado.
During a tornado
At home:
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Go at once to the basement, storm cellar, or the lowest level of the building.
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If there is no basement, go to an inner hallway or a small inner room without windows, such
as a bathroom or closet.
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Get away from windows.
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Go to the center of the room. Stay away from corners because they tend to attract debris.
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Get under a piece of sturdy furniture such as a workbench or heavy table and hold on to it.
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Use arms to protect head and neck.
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If in a mobile home, get out and find shelter elsewhere.
If at work or school:
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Go to the basement or to an inside hallway at the lowest level.
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Avoid places with wide-spa roofs such as auditoriums, cafeterias, large hallways, or
shopping malls.
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Get under a piece of sturdy furniture such as a workbench or heavy table or desk and hold
on to it.
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Use arms to protect head and neck.
If outdoors:
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If possible, get inside a building.
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If shelter is not available or there is no time to get indoors, lie in a ditch or low-lying
area or crouch near a strong building. Be aware of the potential for flooding.
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Use arms to protect head and neck.
If in a car:
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Never try to out-drive a tornado in a car or truck. Tornadoes can change direction quickly
and can lift up a car or truck and toss it through the air.
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Get out of the car immediately and take shelter in a nearby building.
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If there is not time to get indoors, get out of the car and lie in a ditch or low-lying
area away from the vehicle. Be aware of the potential for flooding.
Help injured or trapped persons
Give first aid when appropriate. Don't try to move the seriously injured unless they are in
immediate danger of further injury. Call for help.
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Turn or radio or television to get the latest emergency information.
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Stay our of damaged buildings. Return home only when authorities say it is safe.
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Use the telephone only for emergency calls.
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Clean up spilled medicines, bleaches or gasoline or other flammable liquids immediately.
Leave the buildings if you smell gas or chemical fumes.
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Take pictures of the damage-both to the house and its contents-for insurance purposes.
Remember to help your neighbors who may require special assistance-infants, the elderly, and
people with disabilities.
Inspecting utilities in a damaged home
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Check for gas leaks. If you smell gas or hear a blowing or hissing noise,
open a window and quickly leave the building. Turn off the gas at the outside main valve if
you can and call the gas company from a neighbor's home. If you turn off the gas for any
reason, it must be turned back on by a professional.
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Look for electrical system damage. If you see sparks or broken or frayed
wires, or if you smell hot insulation, turn off the electricity at the main fuse box or
circuit breaker. If you have to step in water to get to the fuse box or circuit breaker,
call an electrician first for advice.
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Check for sewage and water lines damage. If you suspect sewage lines are
damaged, avoid using the toilets and call a plumber. If water pipes are damaged, contact
the water company and avoid using water from the tap. You can obtain safe water by melting
ice cubes.
Thunderstorms and lightning
Severe thunderstorm watches and warnings
A severe thunderstorm watch is issued by the National Weather Service when the
weather conditions are such that a severe thunderstorm (damaging winds 58 miles per hour or
more, or hail three-fourths of an inch in diameter or greater) is likely to develop. This is
the time to locate a safe place in the home and tell family members to watch the sky and listen
to the radio or television for more information.
A severe thunderstorm warning is issued when a servers thunderstorm has been
sighted or indicated by weather radio. At this point, the danger is very serious and everyone
should go to a safe place, turn on a battery operated radio or television, and wait for the
"all clear" by the authorities.
Some thunderstorms can be seen approaching, while others hit without warning. It is important
to learn and recognize the danger signs and to plan ahead.
Learn the thunderstorm danger signs:
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Dark, towering or threatening clouds
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Distant lightning and thunder
Have the following disaster supplies on hand:
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Flashlight and extra batteries.
-
Portable, battery-operated radio and extra batteries.
-
Emergency food and water.
-
Non electric can opener.
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First aid kit and manual.
-
Essential medicines.
-
Cash and credit cards.
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Sturdy shoes.
After a thunderstorm
Check for hazards in the yard. Dead or rotting trees and branches can fall during a severe
thunderstorm and cause injury or damage.
Make sure that all family members know how to respond after a thunderstorm. Teach family
members how and when to turn off gas, electricity and water.
Teach children how and when to call 911 and which radio station to tune to for emergency
information.
Learn how to respond to a tornado and flash flood. (Follow the tips listed above in the tornado
preparedness lists.)
If indoors:
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Secure outdoor objects such as lawn furniture that could blow away or cause damage or
injury. Take light objects inside.
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Do not handle electrical equipment or telephones because lightning could follow the wire.
Television sets are particularly dangerous at this time.
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Avoid bathtubs, water faucets, and sinks because metal pipes can transmit electricity.
If outdoors:
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Attempt to get into a building or car.
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If not structure is available, get to an open space and squat low to the ground as quickly
as possible. (If in the woods, find an area protected by a low clump f trees-never stand
underneath a single large tree in the open.) Be aware of the potential for flooding in
low-lying areas.
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Kneel or crouch with hands on knees.
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Avoid tall structures such as towers, tall trees, fences, telephone lines or power lines.
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Stay away from natural lightning rods such as golf clubs, tractors, fishing rods, bicycles,
or camping equipment.
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Stay away from rivers, lakes, or other bodies of water.
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If you are isolated in a level field or prairie and you feel your hair stand on end (which
indicates that lightning is about to strike), drop to your knees. Do not lie flat on the
ground.
If in a car:
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Pull safely onto the shoulder of the road away from any trees that could fall on the
vehicle.
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Stay in the car and turn on the emergency flashers until the heavy rains subside.
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Avoid flooded roadways.
Estimating the distance from a thunderstorm
Because light travels so much faster than sound, lightning flashes can be seen long before the
resulting thunder is heard. Estimate the number of miles you are from a thunderstorm by
counting the number of seconds between a flash of lightning and the next clap of thunder.
Divide this number by five.
Important: You are in danger from lightning if you can hear thunder. Knowing how far away from
a storm is does not mean that you're in danger only when the storm is overhead.
Hail
Hail is produced by many strong thunderstorms. Hail can be smaller that a pea or as large as a
softball and can be very destructive to plants and crops. In a hailstorm, take cover
immediately. Pets and livestock are particularly vulnerable to hail, so bring animals into a
shelter.
Check for injuries
A person who has been struck by lighting does not carry an electrical charge that can shock
other people. If the victim is burned, provide first aid and call emergency assistance
immediately. Look for burns where lightning entered and exited the body. If the strike caused
the victim's heard and breathing to stop, give cardiopulmonary resuscitation (CPR) until
medical professionals arrive and take over.
Report any downed utility wires.
Drive only if necessary. Debris and washed-out roads may make driving dangerous.
Thunderstorm and lightning facts
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Thunderstorms can bring heavy rains (which can cause flash flooding), strong winds, hail,
lightning and tornadoes. In a severe thunderstorm get inside a sturdy building and stay
turned to a battery-operated radio for weather information.
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Lightning is a major threat during a thunderstorm. In the United States, between 75 and 100
American are hit and killed each year by lightning. If you are caught outdoors, avoid
natural lightning rods such as tall, isolated trees in an open area or top of a hill and
metal objects such as wire fences, golf clubs and metal tools.
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It is a myth that lightning never strikes twice in the same place. In fact, lightning will
strike several times in the same place in the course of one discharge.
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At any given moment, nearly 1,800 thunderstorms are in progress over the surface of the
earth.
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On average, the United States gets 100,000 thunderstorms each year. Approximately 1,000
tornadoes develop from these storms.
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Straight-line winds exceeding 100 mph are responsible for most thunderstorm damage.
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The power of lightning's electrical charge and intense heat can electrocute on contact,
split trees, ignite fires and cause electrical failures.
What is a thunderstorm?
A thunderstorm is formed from a combination of moisture, rapidly rising warm air and a force
capable of lifting air such as a warm and cold front, a sea breeze or a mountain. All
thunderstorms contain lightning. Thunderstorms may occur singly, in clusters, or in lines.
Thus, it is possible for several thunderstorms to affect one location in the course of a few
hours. Some of the most severe weather occurs when a single thunderstorm affects one location
for an extended time.
What is lightning?
Lightning is an electrical discharge that results from the buildup of positive and negative
charges within a thunderstorm. When the buildup becomes strong enough, lightning appears as a
"bolt." This flash of light usually occurs within the clouds or between the clouds and the
ground. A bolt of lightning reaches a temperature approaching 50,000 degrees Fahrenheit in a
split second. The rapid heating and cooling of air near the lightning causes thunder.
*Reprinted courtesy of the Minnesota Department of Public Safety
For more information, contact:
Bloomington Police Department
PH: 952-563-4900, FAX: 952-563-4936
E-mail: police@ci.bloomington.mn.us
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