Natural Disasters

Natural disasters by far account for the greatest loss of life and the greatest amount of property damage than any other type of event.

The United States is becoming more vulnerable to natural hazards mostly because of changes in population and national wealth density--more people and infrastructure have become concentrated in disaster-prone areas.

Worst Earthquake

July 28, 1976 - The world's most devastating quake of the 20th century (magnitude 7.8) hit the sleeping city of Tangshan, in northeast China. The official death toll was 242,000. Some unofficial estimates put the actual

number of dead as high as 655,000.

Worst Volcano

May 8, 1902 - Mt. Pelee erupted on the Caribbean island of Martinique, destroying the capital city of St. Pierre. Up to 40,000 were killed.

Worst Flood

July-August 1931 - Massive flooding of China's Yangtze River led to more than three million deaths from drowning, disease and starvation.

Worst Pandemic

1918-1919 - An epidemic of "Spanish Flu" spread around the world. At least 20 million died, although some estimates put the final toll at 50 million.

It is estimated that between 20 per cent and 40 per cent of the entire world's population got sick.

Worst US Flood

1889 May 31, Johnstown, Pa.: collapse of South

Fork Dam left more than 2,200 dead.

Worst US Hurricane

1900 Sept. 8, Galveston, Tex.: an estimated

6,000–8,000 dead, mostly from devastation due to tidal surge.

Worst US Tornado

1925 March 18, Mo., Ill., and Ind.: great “Tri-State

Tornado”; 689 dead; over 2,000 injured. Property damage estimated at $16.5 million.

Worst US Earthquake

1906 April 18, San Francisco: earthquake

accompanied by fire razed more than 4 sq mi; estimates range from 700 to 3,000 dead or missing.

Natural Disasters

Natural hazards are more predictable than any other hazard.

Although may not know exactly when a natural disaster will occur, precisely where they will strike, or how severe they will be, past experience can be used to identify areas that are most vulnerable to certain types of natural disasters.

Natural Disasters

The largest single category of repetitive threats results from weather or geological events that can affect any area of the country.

Their impact can be localized or widespread, predictable or unpredictable; resulting damage can range from minimal to major.

Natural Disasters

Depending on the severity of the incident, they can have a long-term impact on the infrastructure (roads, bridges, and utilities) of any given location.

Threats involving landslide, tornado, tsunami, volcano, wildlife, thunderstorm, and winter storm.

Natural Disaster Planning Specifically, the following steps are involved in the process:

Writing a management policy Organizing a planning committee Identifying perils or threats and assessing vulnerability to

these hazards Assessing the availability and capabilities of public

emergency services, company personnel, and equipment resources

Deciding the level of response capability based upon local needs and regulatory requirements

Organizing the emergency response team Writing the plan Training personnel Testing the plan

Earthquakes

An earthquake is a wave-like movement of the earth's surface.

The earth's crust and upper part of the mantle are consistently pushing and moving against one another along what are known as fault lines.

When rock masses slip along a fault, the energy of an earthquake is released in seismic waves.

An earthquake also can be produced by volcanic eruptions. Earthquakes can be extremely violent.

Interstate highway collapse in 1989 San Francisco

Earthquake where 41 motorists were killed.

Richter Scale

Richter scale, invented by Charles F. Richter in 1934. The damage caused by an earthquake depends on

its severity or intensity. The most widely known indicator of severity, the

Richter scale, measures the energy released A change of one full point in the Richter scale

represents a difference factor of about 30 in energy released.

Thus, an earthquake of magnitude 7 is roughly 30 times as powerful – in terms of energy released – as one of magnitude 6.

Richter Scale

Richter Magnitudes

Earthquake Effects

Less than 3.5 Generally not felt, but recorded.

3.5-5.4 Often felt, but rarely causes damage.

Under 6.0 At most slight damage to well-designed buildings.

Can cause major damage to poorly constructed buildings over small regions.

6.1-6.9 Can be destructive in areas up to about 100 kilometers across where people live.

7.0-7.9 Major earthquake. Can cause serious damage over larger areas.

8 or greater Great earthquake. Can cause serious damage in areas several hundred kilometers across.

Modified Mercalli (MM) Intensity scale Another scale is the Mercalli scale. Invented by Giuseppe Mercalli in 1902 Today, geologists use what is known as the

Modified Mercalli (MM) Intensity scale to measure the intensity of ground shaking at a particular site.

Signs and Warnings

Earthquakes usually occur without warning. Earthquake monitoring is conducted by the

U.S. Geological Survey, the National Oceanic and Atmospheric Administration, and universities throughout the United States.

However, the exact time and place an earthquake will occur still cannot be precisely.

Earthquake Risk Maps

Though quakes usually strike without warning, scientists have produced risk maps that show areas where an earthquake is likely to occur.

Other clues to the probability of a quake come from studying faults, measuring the tilt of the earth's crust, watching changes in the water levels of wells, and even observing the behavior of animals.

Immediate Dangers

The actual movement of the ground is seldom the direct cause of death or injury.

Earthquake-related casualties are commonly caused by: partial or total building collapse, including toppling chimneys

or walls, falling ceiling plaster, light fixtures, and pictures; flying glass from broken windows and skylights (this danger

may be greater from windows in high-rise structures): overturned bookcases, fixtures, and other large furniture

and appliances; fires from broken chimneys and broken gas lines: fallen power lines; and an inappropriate or drastic human reaction caused by fear.

Secondary Emergencies

Fires caused by earthquakes are particularly dangerous.

Water mains may be broken and fire-fighting equipment may be unable to reach the fire.

Broken gas lines often are a major cause of earthquake-related fires. Damage to buildings, utility lines, bridges, or dams.

Water supplies can become contaminated by seepage around broken water mains.

Damage to roadways and to other means of transportation may create food and other resource shortages if transportation is interrupted.

Advanced National Seismic System Network The Advanced National Seismic System

Network will be a nationwide network of at least 7000 shaking measurement systems, both on the ground and in buildings.

Advanced National Seismic System Network Provide emergency response personnel

with real-time earthquake information. Provide engineers with information about

building and site response. Provide scientists with high-quality data to

understand earthquakeprocesses and solid earth structure and dynamics.

Seismic Probability MapsU.S. Geological Survey Hazard maps are available from the US

Geological Survey http://earthquake.usgs.gov/research/hazmaps/

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Floods

Floods can be slow or fast rising. They are sometimes seasonal, as when

winter or spring rains and melting snow fill river basins with too much water too quickly.

Flash floods are usually the result of extremely heavy rain or snow and are sudden.

1993 Mississippi Flood The 1993 midwest flood was one of the most

significant and damaging natural disasters ever to hit the United States.

Damages totaled $15 billion, 50 people died, hundreds of levees failed, and thousands of people were evacuated, some for months.

Comparison Photos of the Mississippi, 1993

Mississippi and Missouri River Basin, 1993

Flood Experiences

On the average, each year more than 300,000 people are driven from their homes by floods, 200 flood-related fatalities occur, and $2 billion in total flood damages are sustained.

The worst recorded flood in terms of loss of lives was the 1889 flood in Johnstown, Pennsylvania, which resulted in the loss of more than 2,200 lives.

FEMA Map Services

Special flood hazard areas for some 18,000 communities are identified on a Flood Hazard Boundary Map or a Flood Insurance Rate Map issued by FEMA.

Many maps provide base flood elevations.

Floodways

FEMA also provides many communities with data to help them designate floodways.

The floodway is that part of the stream channel, plus any adjacent floodplain land, that must be reserved in order to allow the discharge of the base flood ("100-year flood") without increasing flood heights.

National Flood Insurance Program

Every community participating in the National Flood Insurance Program (NFIP) is required to maintain a repository for their flood maps.

The NFIP is a Federal program enabling property owners to purchase flood insurance.

FEMA administers the NFIP in communities throughout the United States.

Communities in the NFIP must require new buildings in the special flood hazard area to be constructed so that the lowest floor will be located at or above the base flood elevation.

Signs and Warnings

A flood may be build in areas near streams and rivers

Monitor radio for flood forecasts Flash floods occur swiftly. Flood warnings are issued by the National

Weather Service. Local police, the sheriff, the highway patrol,

the county flood control district office, and other local agencies may also supply flood warnings.

Signs and Warnings

A flash flood watch is issued when flash flooding is possible within the designated watch area: be alert

A flash flood warning is issued when a flash flood has been reported or is imminent: take necessary precautions

A flood warning is issued as an advance notice that a flood is imminent or is in progress at a certain location or in a certain river basin.

Immediate Dangers

The immediate danger from flash floods is from the strength of the water current as it surges through an area, carrying debris and causing injuries and drowning

Floods can interrupt power, disable fuel sources, and make roads impassable. People may be stranded in their homes, or be unable to reach their homes.

Long Term Dangers

Long-term dangers include the outbreak of disease, widespread animal death, broken sewage lines and widespread water supply pollution broken gas lines, downed power lines, and fires.

Large-scale flooding can disrupt a community for a long time while utilities are restored, debris is cleared, and property is repaired.

Preparedness

Stockpile emergency building materials such as sandbags, plywood, plastic sheeting, and lumber.

Develop an evacuation and preparedness plan.

If in a flash flood area, have several alternate routes to ensure rapid evacuation.

Maintain emergency supplies such as a first aid kit, portable radio,

Store drinking water in jugs and bottles.

Prevention

Avoid building in a floodplains Implement flood prevention strategies into

building designs and equipment designs

Mitigation

FEMA'S The Mitigation Division manages the National Flood Insurance Program (NFIP) and a range of programs designed to reduce future losses to homes, businesses, schools, public buildings and critical facilities from floods, earthquakes, tornadoes and other natural disasters.

Mitigation includes such activities as: Complying with or exceeding NFIP floodplain

management regulations. Adopting zoning ordinances that steer development

away from areas subject to flooding, storm surge or coastal erosion.

Response

As flood waters rise, take these key precautions: Secure all outdoor items or store them inside on upper levels Move all valuable household possessions to upper levels away

from rising floods. Move cars, machinery, and all livestock to higher ground Check emergency food and water supplies – keep them high

and dry. Listen to radio announcements from emergency officials. If you

are told to evacuate, do so immediately. Do not attempt to drive over a flooded road In a flash flood warning, move immediately to high ground. Because of the speed with which a flash flood travels, there is

no time to save any possessions or implement any precautionary measures.

Recovery

Have all drinking water tested by local health authorities before using.

Before entering a building, check for structural damage; make sure it is not in danger of collapsing.

Check utilities Report broken utility lines to appropriate

authorities Keep in mind that floods can cause

landslides, mudflows, and power outages

Tornadoes Tornados are relatively short-lived local storms. They are composed of violently rotating columns of air that

descend in the familiar funnel shape from thunderstorm cloud systems.

The weather conditions that tend to generate tornados are unseasonably warm and humid earth surface air, cold air at middle atmospheric levels, and strong upper-level jet stream winds.

Tornados can occur anywhere in the United States during any month of the year.

The destruction path of a tornado averages about 250 yards in width and 15 miles in length.

However, in extreme conditions, a tornado may travel more than 300 miles and leave a path of total destruction more than a mile wide.

Tornados will travel up to sixty miles per hour, with wind speeds approaching 400 miles per hour within the tornado's center.

SKYWARN Spotters Network

To obtain critical weather information, the National Weather Service of the U.S. Department of Commerce’s National Oceanic and Atmospheric Administration, and cooperating organizations, have established SKYWARN Spotter Networks

Greensburg, KS, June 4, 2007

At 9:45 p.m. CDT on May 4, 2007, Greensburg was hit by an EF5 tornado.

The tornado was estimated to be 1.7 miles in width and traveled for nearly 22 miles.

Ninety-five percent of the city was confirmed to be destroyed, with the other five percent being severely damaged.

The National Weather Service estimated winds of the tornado to reach 205 mph.

Twelve fatalities were attributed to the tornado, ten of them residents of Greensburg.

Tornado sirens sounded in the city twenty minutes before the tornado struck, and a tornado emergency was issued, which undoubtedly saved many lives.

Greensburg, KS, June 4, 2007

Tornado Myths

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.

Signs and Warnings

Tornados develop during severe thunderstorms and hurricanes.

While not all thunderstorms and hurricanes create tornados, the potential is there.

The Enhanced Fujita Scale

The Fujita Scale is used to classify the intensity and damage from tornadoes.

Developed in 1971 by Tetsuya "Ted" Fujita Through extensive research the Fujita Scale was

developed based on damage, not wind speeds Storm researchers came up with the Enhanced

Fujita scale to better reflect a tornado’s strength. The new Enhanced Fujita scale started use in

February  2007.

Tornado Watches and Warnings

The National Severe Storms Forecast Center in Kansas City, Missouri, issues tornado watches.

Local National Weather Service offices issue tornado warnings.

Local officials may sound sirens in a tornado warning. A tornado watch indicates that conditions are right for

a tornado to develop and that the sky should be watched.

A tornado warning indicates a tornado has been sighted or is spotted on radar.

Warnings will give the location of the tornado and the area immediately affected by the warning.

Immediate Dangers

The immediate threat from tornados is danger to life and damage to property from violently whirling winds and debris hurled through the air by winds.

Long-Term Dangers

Long-term risks include the possibility of building collapse, fallen trees and power lines, broken gas lines, broken sewer and water mains, and the outbreak of fires.

Agricultural crops and industries may be damaged or destroyed.

Preparedness

The best preparation for a tornado is to designate a safe place as a tornado shelter.

Tornado shelters are safest if they are underground.

A basement away from windows offers the best protection.

If neither of these are available, plan to find shelter under heavy furniture near an inside wall on the ground floor.

Get under solid furniture.

Prevention

Follow relevant building code practices such as the use of wind-resistant design.

Response

Get to adequate shelter immediately Do not drive. If driving in a city and spot a tornado, get out of your

car and go into a nearby building. If driving in open country, drive at a right angle away

from the tornado's path if you can safely do so. Do not try to outrun the storm. If you cannot avoid the tornado, get out of your car. Lie flat in the nearest depression, such as a ditch,

culvert, or ravine. Protect your head, and stay low to the ground.

Recovery

Communicating with employees, vendors and clients Recovering documents and electronic data Protecting equipment and physical resources Locating alternate physical facilities Finding alternate suppliers/ sources of raw materials Maintaining cash flow Addressing legal issues Processing insurance and medical claims.

Hurricane Preparedness

Hurricane hazards come in many forms: storm surge high winds tornadoes flooding

Storm Surge

Storm surge is simply water that is pushed toward the shore by the force of the winds swirling around the storm. This advancing surge combines with the normal tides to create the hurricane storm tide, which can increase the mean water level 15 feet or more.

Storm Surge

One tool used to evaluate the threat from storm surge is the SLOSH model.

Hurricane Katrina

SLOSH Model

SLOSH (Sea, Lake and Overland Surges from Hurricanes) is a computerized model run by the National Hurricane Center (NHC) to estimate storm surge heights and winds resulting from historical, hypothetical, or predicted hurricanes by taking into account: Pressure Size Forward speed Track Winds

Hurricane Katrina

SLOSH Model

The SLOSH model is generally accurate within plus or minus 20 percent. For example, if the model calculates a peak 10 foot storm surge for the event, you can expect the observed peak to range from 8 to 12 feet.

High Winds

Hurricane intensity measured on the Saffir-Simpson Scale

The scale was developed in 1971 by civil engineer Herbert Saffir and meteorologist Bob Simpson, who at the time was director of the U.S. National Hurricane Center (NHC).

Categories 1-5 Based upon wind speeds

Hurricane Katrina

Estimating Potential Damage from Disasters FEMA’s HAZUS-MH Potential loss estimates analyzed in HAZUS-MH

include: Physical damage to residential and commercial

buildings, schools, critical facilities, and infrastructure;

Economic loss, including lost jobs, business interruptions, repair and reconstruction costs; and

Social impacts, including estimates of shelter requirements, displaced households, and population exposed to scenario floods, earthquakes and hurricanes.