US TORNADOES 2010US TORNADOES 2010

GROUP MEMBERS

BUSHRA NAEEM

FAZEELAT NIAZ

SUMAYYAH KHAN

ZAREEN ALI

Tornadoes are one of nature's most powerful and destructive forces

Tornadoes, sometimes called twisters, or cyclones, are violent windstorms that take the form of a rotating column of air, or vortex, that extends downward from a cumulonimbus cloud.

Some tornadoes consist of a single vortex, but within many stronger tornadoes are smaller intense whirls called suction vortices that rotate within the main vortex.

Tornadoes' distinctive funnel clouds are actually transparent. They become visible when water droplets pulled from a storm's moist air condense or when dust and debris are taken up. Funnels typically grow about 660 feet (200 meters) wide.

Path Length and Speed Tornado paths range from 100 yards to one

mile wide and are rarely more than 15 miles long. They can last from several seconds to more than an hour, however, most don't exceed 10 minutes. Most tornadoes travel from the southwest to northeast with an average speed of 30 mph, but the speed has been observed to range from almost no motion to 70 mph.

Tornado genesis It is not fully understood. 11 different hypotheses to explain the

formation of the tornado. Typically, tornadoes develop several

thousand feet above the earth's surface inside of a severe rotating thunderstorm. This type of storm is called a supercell thunderstorm.

Conditions for Tornadoes Change in wind direction Increase in wind speed Increasing height Rising air within a thunderstorm

Tornado Clues High winds Very large hail Dark, often greenish sky Loud roar; similar to a freight train

Frequency and Seasonal Pattern They occur more often in late afternoon,

when thunderstorms are common More prevalent in spring and summer. However, tornadoes can and do form at

any time of the day and year.

Classification of Tornadoes Weak Tornadoes 69% of all tornadoes Less than 5% of tornado deaths Lifetime 1-10+ minutes Winds less than 110 mp

Strong Tornadoes 29% of all tornadoes Nearly 30% of all tornado deaths May last 20 minutes or longer Winds 110-205 mph

Violent Tornadoes Only 2% of all tornadoes 70% of all tornado deaths Lifetime can exceed 1 hour

Tornadoes around the Globe

Occurrence in the US: No other country has nearly as many

tornadoes as the U.S. The United States has the most

tornadoes of any country, nearly four times more than estimated in all of Europe

It has over 1200 tornadoes per year (but only 2% of those are severe) causing70 fatalities and 1,500 injuries

The conditions that lead to the formation of tornadoes are most often met in the central and southern U.S., where warm, humid air from the Gulf of Mexico collides with cool, dry air from the Rockies and Canada.

Peak months of tornado are April, May, and June. However, tornadoes have occurred in every month and at all times of the day or night. A typical time of occurrence is on an unseasonably warm and sultry Spring afternoon between 3 p.m. and 9 p.m

Tornado Alley In the United States, the area where the

tornadoes hit the most is called Tornado Tornado AlleyAlley. The states which are in the tornado alley are:

Texas Nebraska Colorado Iowa

Illinois

Indiana

Missouri

Arkansas

US Tornadoes 2010

There were 1,531 tornadoes reported in the US in 2010 (of which at least 1,266 were confirmed), with 45 confirmed fatalities.

Tornado Outbreaks The March 2010

Carolinas tornado outbreak

March 28, 2010. 13 confirmed

tornadoes Southeast United

States

The April 2010 tornado outbreak

April 22–25, 2010 88 confirmed

tornadoes Southern United

States, High Plains the Mississippi and Tennessee Valleys.

The May 2010 tornado outbreak

May 10–13, 2010 91 confirmed

tornadoes Oklahoma,

Kansas, and Missouri

The Mid-June 2010 tornado outbreak

June 16-17, 2010 82 confirmed

tornadoes Midwest and

Northern Plains of the United States

Forecasting Tornadoes and Outlooks

Because severe thunderstorms and tornadoes are small and short-lived phenomena, they are among the most difficult weather features to forecast precisely.

When necessary, the Storm Prediction Center of the National Weather Service issues severe thunderstorm outlooks several times daily.

Doppler Radar With its ability to detect air motion within a

cloud, Doppler radar technology has greatly advanced the accuracy of tornado warning.

Using the principle known as the Doppler effect, Doppler radar can identify the initial formation and subsequent development of the mesocyclone within a thunderstorm that frequently precedes tornado development.

Doppler on Wheels -- DOWMobile radar with tornado

© Joshua Wurman

Causes of tarnado

Super cells. Most strong and

violent tornadoes occur with super cell thunderstorms.

Winds turn from south to west with height.

Cont…. Instability Instability refers to unusually

warm and humid conditions in the lower atmosphere, and possibly cooler than usual conditions in the upper atmosphere.

Low pressure systemThe intense spinning of a

tornado is partly the result of the updrafts and downdrafts in the thunderstorm .

Formation of tornado

Step 1Before a t-storm, a

change in wind direction and an increase in speed forms an invisible, horizontal spinning effect in the lower atmosphere (at the base of the storm)

Step 2Rising air within the

t-storm (updrafts) tilts the rotating air from horizontal to vertical

Step 3Vertical rotation

now extends 2-6 miles up into the t-storm. Now a tornado may form and extend from this area of rotation to the ground.

vulnerability vulnerability is conditions (susceptibility) that

reduce the ability of people or places to respond to and recover from environmental threats, while vulnerability is the degree to which different social groups are at risk from hazards .

Types of vulnerability Physical

Economical

Locational

Social

Physical vulnerability Mobile home residents

Mobile home residents are known to be highly vulnerable to tornadoes.

Mobile home residents are more vulnerable than permanent home residents.

Locational vulnerability Demographic shifts from the Northeast and

Midwest to the South and eastern coastal areas amplified the hazard potential in these areas.

Riebsame. (1986) noted similar demographic shifts to ‘Sunbelt’ states in the West and the South, which may have helped to increase the vulnerability of these areas to weather-related hazards

Factors effects social vulnerability False Alarm Rate . Simmons and Sutter (2010) noted tornadoes occurring in

areas with higher FAR tend to cause more death and injury .

For example, a one standard deviation increase in the FAR raised death rates between 12 and 29% and injury rates between 14 and 32%.

Ashley in 2010 identified the American south region is more vulnerable to tornado.

According to him many factors make south region more vulnerable, mobile home density, seasonality, the day of time tornado strike and resident attitudes.

Cont… Ashley in 2010 identified the American

south region is more vulnerable to tornado.

According to him many factors make south region more vulnerable, mobile home density, seasonality, the day of time tornado strike and resident attitudes.

The Fujita ScaleMost tornado damage is caused by tremendously

strong winds. One commonly used guide to tornado intensity is

the Fujita Intensity Scale, or simply F-scale. A rating on the F-scale is determined by assessing

the worst damage produced by a storm. Although most tornado damage is done by violent

winds, most tornado injuries and deaths result from flying debris.

Fujita Wind-Damage Scale

Six levels: F0: Light damage F1: Moderate damage F2: Considerable damage F3: Severe damage F4: Devastating damage F5: Incredible damage

Fujita-Pearson Tornado Scale F-0: 40-72 mph, chimney damage, tree

branches broken F-1: 73-112 mph, mobile homes pushed

off of foundations or overturned F-2: 113-157 mph, considerable damage,

mobile homes destroyed, trees uprooted F-3: 158-205 mph, roofs and walls torn

down, trains overturned, cars thrown

F-4: 207-260 mph, well constructed walls are leveled

F-5: 261-316 mph, homes lifted off foundations and carried considerable distances, autos lifted as far as 100 meters

DESTRUCTION FROM TORNADOES IN U.S

A tornado can be the most horrific and threatening of all natural disasters.

Most deaths are caused by flying debris.

CONT . . . . .

Tornadoes develop from thunderstorms.

Tornadoes vary in speed, size, and time limits.

Regions of Tornadoes in United States:

Florida

Tornado Alley

The Alley of Destruction: Tornado Alley

Definition

Occurrence

What makes this area Tornado Alley?

Timing

U.S APRIL 2O1O TORNADOES OUTBREAK:

Types of Tornado Damage

Tornadoes are violent, unpredictable windstorms in which winds can reach up to 225 mph and devastate the areas through which they pass. Many dangers are associated with tornadoes, both immediate and long-term, and anyone caught in a tornado should seek shelter below ground or in a concrete room away from windows until the storm has passed.

Wind Damage

The strong winds present during a tornado can uproot trees and level buildings. Sudden changes in air pressure due to the force of moving air currents can shatter windows and stress structures such as homes and barns when the building expands or contracts. A tornado can tear the roof or entire stories from a building as it passes. Tornado-force winds can also cause phone, power and other utility lines to break and fall.

Damage From Debris

Flying debris can destroy property and even kill people during a tornado. Even tiny objects such as pebbles or straw can penetrate much larger objects when speeding through the air, damaging buildings, automobiles and other structures.

Long-Term Damage

Even after a tornado has passed, there are dangers in its wake. Downed power lines can pose serious risks of electric shock and death. Bridges and other infrastructure may be weakened from wind damage or debris, and buildings may be unsafe to enter for the same reasons.

High Speed Collisions and Impacts

A person, animal or object can be swept through the air or over considerable distances along the ground by tornado winds. When caught in these winds, a collision with stationary objects or the ground is not only likely, but potentially fatal.

Hazards and Impact of U.S Tonadoes: Hazards from Tornadoes Extremely Strong Winds and Flying

Debris Strong Updrafts Subsidiary Vortices Abrupt drop in Pressure

Direct Costs Loss of Life

Injuries

Property Damage

Transportation

Interruption of Economic Activity

Disruption of Power, Communications, Drinking Water.

Damage from Tornadoes & Individual Response Investment in

Construction

Listening to Radio or TelevisionResponse to Visual Signs

Confidence in Warning System

Mental and Physical Stress

Social Response Funding for Research

Disaster awareness and Education

Community Shelters

Community Support Systems

Tornado Safety tips

Prepare for tornadoes by gathering emergency supplies

take shelter indoors Avoid windows and seek

additional protection by getting underneath large, solid pieces of furniture

Avoid automobiles and mobile homes, which provide almost no protection from tornadoes.

Long-Term Tornado Recovery Disaster Services has worked hard to ensure

that families receive the support and care they deserve.

This support began with a call for help which was answered by hundreds of volunteers who worked over 1,000 hours to help families clean-up and rebuild. Next, LSSMN Disaster Services helped the citizens of Wadena develop the Wadena/ Otter-Tail Long Term Recovery Committee (WOLTRC), which was

Cont. established to help develop resources for

the rebuilding and recovery efforts in Wadena and Otter Tail counties. Then, LSSMN hired and continues to supervise staff in disaster case management, volunteer recruitment and reconstruction management to support families as they work through this difficult time in their lives.

Disaster Case Management has assisted 139 families locate the resources to rebuild their lives and homes and has helped WOLTRC distribute over $265,000. By recruiting dozens of volunteers and supervising those volunteers many homeowners are finally moving back “home”.

financial support can help people in these communities to rebuild and recover.

Emergency Disaster Service (EDS) Emergency Disaster Service (EDS)

personnel from divisions in the Southern Territory are providing food, drink, emotional and spiritual care to the victims and other resources, like clean-up kits, are available as needed in a number of areas.

Tornado Safety in Schools

Develop a severe weather action plan and have frequent drills,

Each school should be inspected and tornado shelter areas designated by a registered engineer or architect

If the school's alarm system relies on electricity, have a compressed air horn or megaphone to activate the alarm in case of power failure.