As a member of FEMA’s Hazard Mitigation disaster workforce, you are expected to be able to explain to the public:

1. Future risks associated with the hazard event that resulted in the disaster declaration
2. Mitigation measures available to improve personal safety and reduce or eliminate the risk of future damages to structures and personal property

This independent study course is part of a series of five, intended for the Hazard Mitigation disaster workforce. These courses address basic mitigation measures to reduce risk from earthquakes, floods, hurricanes, tornadoes, and wildfires, at a level appropriate for communication to the general public. For more information about the other courses, refer to the EMI website available at https://training.fema.gov.

Course Goal

The goal of this course is to enable you to select the essential hazard mitigation information to communicate to members of the public following a tornado event.

To help accomplish this goal, you will learn about:

• Two types of winds that cause damage
• Mitigation measures specific to manufactured housing
• The importance of directing impacted individuals to local building officials, engineers, and other specialists before starting repairs
• Official FEMA information, publications, and websites that support the mitigation recommendations made to the public

This lesson provides an overview of the course and an introduction to various course features and functionality.

At the end of the lesson, you should be able to describe the:

• Course structure
• Screen features and navigation
• Knowledge Check functionality
• Course credit requirements

Take a moment to review the Lesson List located on the right side of your screen.

This course has five lessons. The lessons may be accessed sequentially or independently. The time to complete each lesson varies. A page tracker is displayed at the bottom middle of the screen to help you gauge your movement through the lesson. The estimated time required to complete each lesson will be stated on the lesson’s first screen.

After completing the course, take the Final Exam to:

• Gauge your knowledge of the topic
• Receive credit for taking the course

This completes this lesson.

In this lesson, you learned:

• What this course is about
• How to complete this course
• How to receive credit for this independent study course

There are two types of winds associated with tornadoes and severe thunderstorms:

• Rotating vortex
• Straight-line

Each type of wind causes damage in different ways; therefore the mitigation measures are specific to each wind type.

In this lesson you will:

• Examine how rotating vortex winds cause damage to structures
• Learn about mitigation measures to help protect people from the effects of vortex wind, including the use of safe rooms and shelters

At the end of this lesson you will:

• Recognize tornado damage caused by rotating vortex winds
• Identify FEMA-recommended actions to protect life from rotating vortex winds

The National Weather Service website at https://www.weather.gov/phi/TornadoDefinition defines a tornado as a violently rotating column of air touching the ground, usually attached to the base of a thunderstorm. 

The tornado's violently rotating column of air is usually visible because of the dust and debris that it carries. The forward speed of a tornado may vary from nearly stationary to 70 mph. The destruction and injury caused by a tornado depends on the intensity, size, path, time of day, and the amount of time that the tornado is on the ground.

The strongest tornadoes have rotating vortex winds of more than 200 mph. It is this extreme force that:

• Rips structures apart
• Destroys trees
• Lifts vehicles off the ground

The same storm that spawns tornadoes may also have strong straight-line winds. We will talk about straight-line winds in the next lesson.

Most injuries and fatalities from tornadoes are caused by being struck or cut by falling or wind-borne debris. The only effective life-safety protection from the vortex of a strong tornado is a safe room or shelter specifically designed to withstand a tornado’s destructive force.

Safe rooms built within a secure structure can protect individuals from the high winds and flying debris associated with tornadoes.

Properly constructed residential and community safe rooms built to the standards of FEMA Publication 361: Safe Rooms for Tornadoes and Hurricanes, provide near absolute protection that reduces the risk of injury or death from the dangerous forces of extreme winds. A community safe room is intended for larger populations such as schools or areas with larger vulnerable populations. Safe rooms can be built as stand-alone projects or as a retrofit of existing interior rooms.

Additional information and some prescriptive plans about residential tornado safe rooms can be found in FEMA Publication 320: Taking Shelter from the Storm.

FEMA 320: Taking Shelter from the Storm and FEMA 361: Safe Rooms for Tornadoes and Hurricanes are discussed in more detail in lesson 5 of this course.

If it is not possible or cost effective to build a safe room within an existing structure, a stand-alone shelter is the better option.

External shelters may be constructed:

• Above grade
• Partially above-grade
• Below grade

Occupants of dwellings who do not have safe rooms or access to shelters or safe rooms should identify the best available refuge area within their homes before a tornado or high wind event occurs.

When people identify and take refuge in the best available space within a building, they are less likely to be injured or killed.

However, it is important to remember that “best available refuge areas” are not specifically designed as storm shelters or safe rooms, so occupants still may be harmed during a tornado.

• Types of damage caused from a vortex wind
• Mitigation measures for protecting human lives from vortex winds, including safe rooms and shelters

Straight-line winds can also cause damage to property and carry a risk of casualties.

Straight-line winds rushing outward from a severe thunderstorm can be similar to the winds of a hurricane.

In this lesson you will learn about:

• Straight-line wind damage to structures and measures that mitigate or reduce the risk of these damages in future wind events
• Other mitigation activities outside of the structure that can lessen damage to property and improve life safety, including measures for outbuildings, and trees

At the end of this lesson you will:

• Recognize wind damage caused by straight-line winds
• Recall the purpose and procedure for hardening a structure using a continuous load path
• Identify mitigation measures to reduce risk of damage from straight-line winds to the roof, windows, and doors
• Recognize opportunities to reduce damage from straight-line winds by anchoring outbuildings and pruning or eliminating trees near structures

Straight-line winds are any wind not associated with the rotation of a tornado. Straight-line, high-velocity winds can exert significant force, or “loads,” on structures. Straight-line winds may also be called a derecho, thunderstorm outflow, or microburst. Straight-line winds may:

• Tear off all or part of a roof
• Break windows
• Damage siding
• Cause a structure to collapse completely
• Blow down trees and vegetation

Many wind mitigation activities involve enhancing a structure’s building performance to resist these loads.

Mitigation actions to reduce the risk of damage to structures from these winds requires connecting and reinforcing the connections between the main parts of a structure to create a continuous load path.

When all of the connections are properly reinforced, wind loads can be effectively transferred from the top of the structure to its foundation in the ground. The important connections in this path are:

• Roof to upper floor walls
• Upper walls to lower walls
• Lower walls to main floor
• Main floor to foundation

Metal brackets and straps, often called “hurricane straps,” are used to strengthen these connections. To be effective, these brackets and straps should be attached at the studs and rafters, not to the plywood sheathing.

When all of the connections are properly reinforced in this manner, a building is less likely to collapse.

Roof failures are a common cause of major damage to buildings and their contents from high winds. There are mitigation measures that can be taken to reduce potential roof damage.

These mitigation measures include:

• Designing Wind-resistant Roofs
• Reinforcing Gable Roof Ends
• Securing Sheathing Properly
• Installing Shingles Properly

In new construction or roof replacement in high-wind hazard areas, installing a hip roof increases the strength of the roof framing and its wind performance.

A hip roof is more resistant to wind damage than a gable-style roof because hip roofs are sloped on all sides. The slopes of a hip roof do not resist winds, while the ends of a gable roof present large obstacles to the full force of the wind.

The shingles are the first part of a roof to experience damage from high winds. Choosing the right shingle and installing it properly is the best way to reduce the risk of wind damage.

While shingles are available in different wind speed and durability ratings, the rating systems are not standard among manufacturers. In general, roof shingles with longer warranties provide greater durability.

Local building codes provide specific installation requirements, but two conventional installation guidelines are:

• Roofing nails perform better than staples or adhesives in high winds.
• Stainless steel nails are recommended when building within 3,000 feet of salt water.

Exterior doors and windows are the weakest parts of a structure’s outer shell. If they are broken or blown in, high winds can enter a structure and create internal pressures which act on the roof and walls, resulting in serious damage. Once the structure is breached, wind, debris, and rain can damage the interior of the structure or injure any person inside.

Breach point mitigation measures include:

• Reinforcing Garage Doors
• Securing Double-entry Doors
• Installing Impact-resistant Glass

Windows are particularly vulnerable components on most structures. High winds and wind-blown debris can break unprotected windows and then enter a building. Once inside, wind and debris can cause more damage. Impact-resistant glass is intended to:

• Prevent damage to the building
• Reduce the likelihood that people will be hurt by broken glass and debris
• Prevent water entry and further damage through broken windows

Impact-resistant glass is laminated with a thin film to keep the glass from shattering. It is also sealed to its frame with structural adhesive.

Other actions can be taken to help protect people, their homes, and other structures from the high winds. If a structure has any unattached buildings or trees near it, there may be opportunities to mitigate possible damage resulting both to and from these objects.

Mitigation measures include:

• Anchoring outbuildings
• Pruning and thinning trees

• How straight-line winds cause damage
• How a continuous load path can mitigate straight-line loads
• How specific components of a building are affected by straight-line winds and mitigation measures to reduce or prevent damage to property and people
• Other mitigation opportunities outside of the structure that can lessen damage and improve life safety

Manufactured homes require special mitigation techniques to help resist the high-wind loads.

Like other structures, damage includes risk of blown-off roof panels, loss of roof framing, loss of wall panels and framing, and window breakage. Window damage can result from wind-borne debris or from the force of the wind.

However, because of how they are constructed and installed on the site, manufactured homes also may experience damage if the anchoring system fails, resulting in the shifting or rolling of the home off of its foundation.

• Mitigation actions to help reduce the risk of damage to manufactured homes from high winds

At the end of this lesson you will be able to:

• Recognize the different damages possible to manufactured home from high winds
• Identify the mitigation measures that will reduce the risk of these damages

Damage to new manufactured homes often is the result of connection failures. Examples are nails or staples that do not secure roofing, siding, or roof sheathing, or poorly-secured wall sheathing that pulls out and allows damage to the home.

Adding fasteners and straps to improve wind performance usually involves temporarily removing siding, roofing, or sheathing to secure the framing of the home. For that reason, this type of mitigation activity is more likely to be implemented on the manufactured home during maintenance activities or when it is being repaired.

When a manufactured home is lifted, slides, or is rolled off its foundation, an “anchorage failure” has occurred.

An anchorage failure can destroy a home, even when there is no wind damage.

The risk of anchorage failure can be reduced through the following mitigation actions:

• Installing and Maintaining Proper Anchors
• Building a Conventional Foundation

A qualified engineer can design anchoring systems and foundations according to the manufacturer’s requirements, local codes, and any circumstances specific to the local geography and climate.

In most manufactured homes, anchorage is provided by ground anchors and steel straps.

Ground anchors are designed to move slightly when loads are applied. In fact, they derive much of their resistance to wind loads through this movement. To be effective, the correct ground anchors for the soil type must be selected. Then once installed, the straps should be inspected regularly, and all corroded or substandard straps or anchors removed and replaced.

The potential for damage to manufactured homes significantly increases when additions like carports, awnings, or porches are attached to the home

If attachments are being considered, they should be engineered to meet local code requirements.

Most home manufacturer warranties prohibit attachments to their homes unless special provisions to support those attachments were built in during the original construction.

This completes this lesson. In this lesson you learned about:

• Using fasteners and straps to mitigate the impact of connection failures caused by high winds
• Using anchoring systems and foundations to help reduce damage to manufactured homes caused by wind-related anchoring failures
• The potential for increased damage when additions like carports, awnings, or porches are attached to the home

Hazard Mitigation staff have a variety of FEMA resources available to help educate the public on tornado and high-wind mitigation techniques. Other resources are intended for the enrichment of building and emergency management professionals. Spend the time needed to become familiar with the purpose of and audience for the resources and publications that are included in this lesson.

At a disaster, the Hazard Mitigation Community Education and Outreach (CEO) group, in collaboration with the state, will decide which of these approved publications and resources support the Hazard Mitigation Strategy for the disaster.

In this lesson you will learn:

• Why it is important to direct members of the public to local building officials before they begin repairs or rebuilding
• How FEMA addresses the topic of disaster-related mold with the public
• Which FEMA publications are available to help the public understand tornado mitigation
• Which organizations offer mitigation information on their websites that complements the information provided by FEMA

At the end of this lesson you will:

• Identify why the public should be directed to local building officials before repairing or rebuilding structures damaged in a tornado or by high winds
• Recognize the information and advice to provide regarding mold
• Select websites that contain FEMA mitigation publications and FEMA partner organizations that promote tornado and wind mitigation

When advising members of the public about reducing the risk of future hazard damages, always tell them to visit the local building official before beginning any repairs or rebuilding because:

• Building codes, permits, inspection requirements, and zoning ordinances may be involved
• A floodplain ordinance will affect rebuilding when the structure has sustained substantial damage and is situated in a floodplain
• Building officials will reinforce the point that only licensed professionals are qualified to perform structural repair or structural mitigation work

Heavy rains often accompany tornadoes and high wind events. If water enters a damaged structure and there is sufficient moisture left inside, conditions will be favorable for mold to grow.

Some basic facts about mold that can be shared with the public are:

• Mold grows where there is sufficient moisture.
• Musty or earthy odors may indicate mold.
• Walls that are not completely dry may allow mold spores to grow quickly.
• Mold exposure may cause or aggravate asthma or respiratory problems in adults and children.
• Mold can cause structural damage to buildings – the longer it grows the more damage it can cause.
• Cleaning to remove the mold without fixing the moisture problem will most likely result in the mold coming back.

Clean-up of mold does not protect a building from mold recurring in future hazard events. However, it does reduce the risk of illness and additional damage from the mold conditions created by the flooding.

Several federal agencies also publish information about mold, including:

• Centers for Disease Control
• Environmental Protection Agency
• FEMA
• U.S. Public Health Service

Hazard Mitigation staff distribute ONLY the mold publication provided by the Hazard Mitigation Community Education and Outreach Group.

FEMA has one post-disaster mitigation grant program to assist communities in reducing long-term hazard risk.

Individuals are not eligible to apply for these grants but may participate in a community initiative. This is one of the reasons for directing individuals to local officials to discuss hazard mitigation options.

If local officials have questions about mitigation grant programs direct them to the State Hazard Mitigation Officer or a FEMA Hazard Mitigation Grant Specialist at the Joint Field Office (JFO). Ask your supervisor for the correct contact information.

NFIP has provisions for financial relief to individual policy holders whose homes:

• Were built prior to the current floodplain ordinance
• Are located in a Special Flood Hazard Area and are substantially damaged by flooding

Refer individuals who may meet these criteria to their flood insurance agent or a Hazard Mitigation Insurance Specialist to find out how to file a claim for Increased Cost of Compliance.

Below are several FEMA publications on reducing the risks related to tornado damage. These can also be accessed from the FEMA website.

• Taking Shelter From the Storm: Building a Safe Room For Your Home or Small Business Design
• Safe Rooms for Tornadoes and Hurricanes: Guide for Community and Residential Safe Rooms
• 2007 Tornado Recovery Advisories
• Tornado Protection: Selecting Refuge Areas in Buildings

This publication will help members of the public decide how best to provide near-absolute protection for themselves, their families, or employees, and answers many questions concerning safe rooms.

Taking Shelter From the Storm: Building a Safe Room For Your Home or Small Business Design is available at https://www.fema.gov/media-library-data/1418837471752-920f09bb8187ee15436712a3e82ce709/FEMA_P-320_2014_508.pdf

This publication offers important information about the design and construction of community safe rooms for twelve to several hundred people. Note that this document is for local governments and other groups intending to build community safe rooms, not individual homeowners.

Safe Rooms for Tornadoes and Hurricanes: Guide for Community and Residential Safe Rooms is available at https://www.fema.gov/media-library-data/1467990808182-0272256cba8a35a4e8c35eeff53dd547/fema_p361_July2016_508.pdf

These fact sheets cover a variety of tornado mitigation topics.

• Recovery Advisories from the Tornado MATs for Alabama, Mississippi, Tennessee, Georgia, and Missouri (2011) webpage available at https://www.fema.gov/media-library/assets/documents/22024 has links to eight (8) new Recovery Advisories (RAs) from the Tornado Mitigation Assessment Teams (MATs) for Alabama, Mississippi, Tennessee, Georgia, and Missouri.


• Tornado Risk and Hazards in the Southeaster United States, February 2007 available at https://www.fema.gov/media-library-data/20130726-1604-20490-5503/2007_tornado_recoveries1.pdf includes:
• Storm Shelters: Selecting Design Criteria
• Residential Sheltering: In-Residence and Stand-Alone Shelters
• Understanding and Improving Performance of Older Manufactured Homes During High-Wind Events
• Understanding and Improving Performance of New Manufactured Homes During High-Wind Events


• Tornado Risk and Hazards in the Midwest United States, February 2007  available at https://www.fema.gov/media-library-data/20130726-1619-20490-0806/ra1_tornado_risks_in_midwest_us_final_9_14_07.pdf

This publication presents information that will aid qualified architects and engineers in identifying the best available refuge area in existing buildings

Tornado Protection: Selecting Refuge Areas in Buildings is available at https://www.fema.gov/media-library-data/20130726-1456-20490-4099/fema_p_431.pdf

Some of FEMA’s hurricane mitigation publications also contain information and illustrations that reinforce principles of wind mitigation. Be sure to differentiate between measures that are effective against tornado vortex winds and those effective against straight-line winds.

• FEMA's Mitigation Assessment Team (MAT) reports
• FEMA’s Home Builder’s Guide to Coastal Construction: Technical Fact Sheet Series
• The How-To Series: Protecting Your Property from Wind
• Avoiding Hurricane Damage: A Checklist for Homeowners

After especially large and destructive disasters, FEMA’s Building Science Branch may send a Mitigation Assessment Team (MAT) to review the damage patterns and to list possible changes in construction and regulations that could mitigate future losses.

To find tornado-related MAT reports, go to the FEMA Mitigation Assessment Team (MAT) Reports web page available at https://www.fema.gov/fema-mitigation-assessment-team-mat-reports and expand the Natural Disaster Reports and Presentations option.

Scroll down until you see the Tornadoes header. The publications listed have been developed by the Building Science Branch of FEMA's Federal Insurance and Mitigation Administration (FIMA). They cover natural and man-made disasters.

This publication is designed for building contractors and trades involved in coastal construction. Several of the fact sheets illustrate measures to reduce the impact of high winds on residential buildings.

High-wind related fact sheets include:

• Siding Installation in High-Wind Regions available at https://www.fema.gov/media-library-data/20130726-1537-20490-5098/fema499_5_3.pdf
• Attachment of Brick Veneer in High-Wind Regions available at https://www.fema.gov/media-library-data/20130726-1537-20490-2673/fema499_5_4.pdf

These publications provide information to homeowners and construction professionals on securing and protecting windows, doors, roofing, garage doors, and Exterior Insulation Finishing System (EIFS) walls.

The Protect Your Property from High Winds How to Series is available at https://www.fema.gov/media-library/assets/documents/13270. From there you can select one or more of the topic areas.

This publication provides the homeowner with an action item fact sheet for what can be done to protect the home from damage due to high winds and flooding. Hurricanes are often accompanied by tornadoes. A property may not be in the path of a tornado but still damaged by the high winds of the storm.

Avoiding Hurricane Damage: Action Items for Homeowners fact sheet is available at https://www.fema.gov/media-library-data/1502885361653-0192e680f333456f9037081bd0e320b9/Avoiding-Hurricane-Damage-2017_508.pdf.

There are several websites that contain tornado mitigation information. Aside from official FEMA websites, there are FEMA-partner organizations that provide comprehensive, user-friendly information and guidance on tornado mitigation.

• FEMA’s Hazard Mitigation Disaster Workforce Website (located behind the FEMA firewall)
• Institute for Business & Home Safety (IBHS)
• Federal Alliance for Safe Homes, Inc. (FLASH)
• National Association of Home Builders

FEMA has one post-disaster mitigation grant program to assist communities in reducing long-term hazard risk.

Individuals are not eligible to apply for these grants but may participate in a community initiative. This is one of the reasons for directing individuals to local officials to discuss hazard mitigation options.

If local officials have questions about mitigation grant programs direct them to the State Hazard Mitigation Officer or a FEMA Hazard Mitigation Grant Specialist at the Joint Field Office (JFO). Ask your supervisor for the correct contact information.

The National Association of Homebuilders (NAHB) represents the building industry for members and affiliated state and local builders’ organizations. The National Association of Homebuilders (NAHB) website is available at www.nahb.org.

The site includes recommended mitigation strategies for most types of natural hazards.

When speaking with members of the public about reducing the risk of future hazard damages:

1. Explain the risk and the mitigation activities clearly and at a level of detail appropriate to the listener.
2. Refer to publications and websites that reinforce or provide additional information about rebuilding or repairing to reduce future risk of damages.
3. Do not give specific repair directions. ALWLAYS direct people to local building officials when they are planning repairs or mitigation.

Remember that you are THE face and voice of hazard mitigation. What you say and do makes a real difference in people’s lives!

This completes the final lesson in this course. In this lesson you learned about:

• Where to find official FEMA publications and partner websites for educating yourself and the informing the public about tornado and wind mitigation
• What appropriate actions to take when advising the public