Defined as a violently rotating column of air extending from a thunderstorm to the ground.

Tornadoes

• Occur in many parts of the world • Found most frequently in the United States east of the

Rocky Mountains • Most frequent during the spring and summer months. • An average of 800 tornadoes are reported nationwide

each year • 80 deaths and over 1,500 injuries average per year. • Capable of tremendous destruction with wind speeds

of 250 mph or more. • Damage paths can be in excess of one mile wide and 50

miles long.

Tornado Formation

Tornado Formation cont.d...

Tornado Formation Cont’d

• Change in wind direction along with an increase of speed causes horizontal spinning effect.

• Rotating air tilts becoming vertical, forming funnel shape.

• Funnel extends to the ground becoming the Tornado.

• “Wall cloud”-slow rotating cloud, parent to the Tornado.

When and Where they occur

•Southern states- March-May

•Northern states- Summer months.

• Mainly in the US but can occur anywhere

Historical Tornado Statistics for Southeast Lower Michigan(updated through 2001 season)

Wayne County All Counties

“Watches” versus “Warnings”

“Watch”- tornadoes are possible in your area

A tornado watch is issued by the National Weather Service when tornadoes are possible in your area. Remain alert for approaching storms. This is time to remind coworkers where the safest places within your office are located, and listen to the radio or television for further developments.

“Warning”- tornadoes have been sighted by weather radar

Many people confuse their meanings

A lower cloud base in the center of the photograph identifies an area of rotation known as a rotating wall cloud. This area is often nearly rain-free. Note rain in the background.

Moments later a strong tornado develops in this area. Softball-size hail and damaging "straight-line" winds can occur with this storm.

Look out for: •Dark, often greenish sky •Wall cloud •Large hail •Loud roar; similar to a freight train

• Some tornadoes may form during the early stages of rapidly developing thunderstorms.

• Occasionally, two or more tornadoes may occur at the same time.

• Tornadoes may appear nearly transparent until dust and debris are picked up.

• Waterspouts are weak tornadoes that form over warm water.

Different types of Tornado

1. The “Wedge” Tornado

• Straight on sides- not funnel shaped.

• Not stronger than a funnel shape but cover larger areas causing more damage.

Different types of Tornado

2. Another wedge with a different appearance

• Appear as a boiling well of fog as they are positioned close to the rain wall.

• The rain stops and the tornado appears

• Often blamed for striking without warning.

Different types of Tornado

3. Classic funnel but white.

• Tornado seen here is front lit by the sunlight so appears white

•Most Tornadoes are photographed from the west so appear black or grey

Different types of Tornado

4. Discontinuous funnel in the rain

• An example of what might lurk in a tornadic storm

• This funnel made a sudden appearance from out of the rain.

Classification of |Tornadoes• Done using the “Fujita Scale”

F-0: 40-72 mph, chimney damage, tree branches brokenF-1: 73-112 mph, mobile homes pushed off foundation or overturnedF-2: 113-157 mph, considerable damage, mobile homes demolished, trees uprootedF-3: 158-205 mph, roofs and walls torn down, trains overturned, cars thrownF-4: 207-260 mph, well-constructed walls leveledF-5: 261-318 mph, homes lifted off foundation and carried considerable distances, autos thrown as far as 100 meters

• Tornadoes hide in many ways -- under cover of darkness, heavy rain, landscape.

• They usually develop in areas in which a severe thunderstorm watch or warning is in effect. Remain alert to signs of an approaching tornado and seek shelter if threatening conditions exist

MYTH: Areas near rivers, lakes, and mountains are safe from tornadoes.FACT: No place is safe from tornadoes. In the late 1980's, a tornado swept through Yellowstone National Park leaving a path of destruction up and down a 10,000 ft. mountain.MYTH: The low pressure with a tornado causes buildings to "explode" as the tornado passes overhead.FACT: Violent winds and debris slamming into buildings cause most structural damage. MYTH: Windows should be opened before a tornado approaches to equalize pressure and minimize damage. FACT: Opening windows allows damaging winds to enter the structure. Leave the windows alone; instead, immediately go to a safe place.

• In a home or building, move to a pre-designated shelter, such as a basement.

• Stay away from windows• If an underground shelter is not available,

move to an interior room or hallway on the lowest floor and get under a sturdy piece of furniture.

Interior bathroom was all that was left standing of this house:• Mobile homes, even if tied down, offer little protection from tornadoes and should be abandoned.

• Go to an inside hallway at the lowest level (central 1st floor hallway).

• Stay inside• 1st floor aisle side cubicles under work surface• Rooms (restrooms, etc. adjoining 1st floor aisle• Avoid places with wide-span roofs areas

• Move away from exterior walls and windows• Get under a piece of sturdy furniture such as a cubicle

work surface or heavy table or desk and hold on to it. (Several of the people that survived the Jarrell tornado lived because they had gotten into a bathtub).

• Use arms to protect head and neck.

• Get out of automobiles. • Do not try to outrun a tornado in your

car; instead, leave it immediately.

•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.

•Get out of the car immediately and take shelter in a nearby building.

•If there is no 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.

Vehicle Procedures During a Tornado

•If possible, get inside a building.

•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.

•Use arms to protect head and neck.

Procedures for Outdoors

Conduct tornado drills each tornado season.Designate an area in the office as a shelter, and practice having everyone go there in response to a tornado threat.

Before A Tornado Happens

Tornado Drill Procedures •When the tornado alarm is given you must immediately:

•Always treat any alarm as the real thing.

•Take cover quickly

•Go to the designated tornado shelter for your office.

•Avoid places with wide-span roofs such as auditoriums, cafeterias, large hallways, or shopping malls.

•Get under a piece of sturdy furniture such as a workbench or heavy table or desk and hold on to it.

•Use arms to protect head and neck.

•Safety personnel should monitor the process and fill out the evacuation report.

After the All Clear Is Given

You must follow all procedures set forth in the emergency evacuation policy.

•Report to the designated meeting area for roll call.

•Remain calm, no smoking or talking.

•Follow the directions of safety personnel.

Evacuation Meeting area.

Communications Is Key Element After the Tornado.

Remember to follow the communications procedures set for your department. Staying in touch will help:

•Ease the concerns of family members.

•Formulate a response to the emergency with information supplied by you on the status of the system.

Destruction caused by Tornadoes

Schools out!

Just as well there was no-one in this car!

This church was never the same again

Its troublesome when you’ve got no home to come home to.

Summary

• Tornadoes are a serious problem causing widespread devastation.

• Quick thinking could save lives

Thank you!