Statement of James Lee Witt, Director, Federal Emergency Management Agency, National Press Club 

Release Date: March 28, 2000
Release Number: HQ-00-049a

On May 3, 1999 more than 70 violent tornadoes struck from Texas to the Northern Plains. They left death and destruction in their wake.

A single F5 tornado touched down outside of Oklahoma City at 6:55 in the evening and blasted through Bridge Creek, Moore, Del City and Midwest City, demolishing entire neighborhoods.

Forty-one people died in Oklahoma City and more than 2,750 homes and apartments were destroyed. Another 8,000 homes were damaged.

We have not seen a tornado outbreak like this in 20 years.

In all, 49 people died in Oklahoma and Kansas and nearly 4,000 homes in the two states were completely destroyed.

FEMA responded with all kinds of assistance --- search and rescue, medical teams, mortuary teams, debris clearance and, of course, financial assistance.

We also took the opportunity to look at the kind of damage those tornadoes did to homes and business. We sent in a team of structural engineers, wind engineers and architects.

Their job was to examine the impact of these tornadoes on structures that were in the direct path of the tornadoes - buildings that were near the direct path and those that were on the edge. They were there to try to understand what these tornadoes did to these structures - how and why buildings failed - or did not fail.

We learned a great deal from their research and today we want to share with you what we believe is the most important information to come out of their work.

Unlike what many of us might believe, we do not have to be helpless victims in the face of even the most violent tornadoes.

We already know that safe rooms can save lives.

People who live in parts of the country that often see tornadoes can learn from people living in hurricane-prone regions.

Now I want to make it clear that just about everything in the path of a violent F5 tornado will be reduced to rubble - except well-constructed "safe rooms" and other engineered shelters.

And that's what we saw in Oklahoma City.

But violent tornadoes - such as F4s and F5s - are rare.

And the total area within the direct path -- or the vortex -- of a tornado is estimated to be only about one percent of the total area affected.

So, we know now that there is much we can do to build stronger structures that will stand up even if they are near the direct path of violent tornado - or even in the direct path of weaker tornadoes.

As the video I am about to show indicates, the tremendous flow of wind that surrounds a tornado outside of its vortex can either cause a house to collapse or leave it structurally intact.

(VIDEO)

The simulation you just saw represents the difference between a house that was built with high winds in mind and a home that could not stand up to the inflow winds of a violent tornado.

FEMA's Project Impact - our program to work at the local level to build disaster resistant communities - conducted a survey of people living in tornado-prone areas.

We found that half of the people we surveyed believed there was nothing they could do to save their homes in the face of a nearby tornado.

More importantly, among the half who thought they could do something, not many actually do.

This graphic video clearly shows the minor damage a home can sustain if constructed with the right materials and using proven wind resistant building techniques that go beyond code, such as those used in hurricane-prone areas.

Let me take this opportunity to review what our team found ... some of the conclusions that we have drawn ... and then I have some recommendations for communities, homeowners and businesses.

Residential Structures

The team saw significant damage to thousands of single-family homes, multi-family housing and manufactured homes.

They saw building failures that resulted from wind-borne debris and high winds that produced forces on buildings that they were not designed to withstand.

They saw building failures that resulted from improper construction techniques, poor selection of construction materials and ineffective detailing of connections of homes to foundations, floors to walls and walls to roofs.

Many of these homes were unable to stand up because of the tremendous internal pressure that resulted from breaches in the building envelope that allowed the wind to penetrate the interior of the structure.

A significant cause of breaches in the building envelope appears to be the failure of double-wide garage doors.

Breaches of windows and entry doors also caused significant damage, but the breaches are not as dramatic as those associated with garage doors, which are larger.

Most garage doors were not rated or tested for wind pressures calculated from design wind loads in building codes for one- and two-family homes currently in use throughout the Midwest.

If the garage doors had been designed for the wind speed indicated in the code, damage in inflow areas of weak and strong tornadoes might have been significantly reduced.

Masonry chimneys that fell on roofs caused considerable damage to homes that otherwise had very minor wind damages. This placed the people inside at significant risk of death or injury from falling masonry debris.

The team concluded that the wind speeds that caused these chimney failures were as low as 75 to 85 mph.

We have concluded that there would have been considerably less damage to residential structures if newer building codes and engineering standards had been adopted, followed and enforced.

Constructing homes to the wind provisions of the most recent versions of the codes and standards would have reduced damage in areas near the direct path of a violent tornado - even an F4 or an F5.

Building or upgrading homes to the most recent versions of the codes and standards would have reduced significant damage to homes in the direct path of less violent tornadoes.

Many building failures could have been avoided with better construction techniques, better building materials and the effective use of structural connections.

Non-residential Structures

The team also looked at non-residential structures ... and found that they were vulnerable to the same types of damages as conventionally built residential construction ... including failure of connections ... roofs lifting up ... walls collapsing.

However, compared to residential buildings, the damage typically was not as complete or devastating.

The team believes that this difference is a result of the special construction methods and degree of engineering that is required by model building codes for non-residential buildings.

Building to national wind standards would have reduced or minimized damage in areas affected by inflow winds of all tornadoes.

And it would have reduced damage to non-residential construction.

Better attention to design and selection of materials for connections throughout the structural system would have reduced building failures.

This is true for buildings on the edge of the path of violent tornadoes. And it's true for buildings in direct path of the less violent tornadoes such as F1, F2s or F3s.

Paying close attention to how perimeter wood nails, copings and metal edge flashings are attached - this will help roofs come through such storms better. And it could help reduce air-borne debris.

Another critical point of failure for non-residential buildings is rollup or overhead doors, which can initiate or contribute to major failures of primary structural systems.

Overhead doors that fail near building corners may significantly contribute to the catastrophic failure of exterior walls and roof systems -- especially for pre-engineered metal, light-steel frame buildings.

Just as for residential structures, the breach of the building envelope resulted in extensive collateral damage.

The team found that garage doors and large windows were real problems. All garage and roll-up doors should meet national wind standards.

Manufactured Housing

Manufactured housing did not do as well as conventional site-built detached single-family dwellings. They did not do as well in resisting the inflow winds of violent and strong tornadoes - that is in the areas near the direct path. Nor did they do as well when they were in the direct path of the tornadoes - not even the weaker ones.

This primarily was because they could not resist uplift and overturning - the problem was the anchorage and tie-downs used in the foundations.

On the bright side -- the team found that the newer manufactured homes performed better than the older ones -- especially the double-wide models installed on permanent foundations.

Although permanent foundations performed better in resisting lateral winds, the connections of chassis and perimeter joists to the permanent foundations were not strong enough.

They could not resist even moderate wind uplift and overturning forces at the edge of most tornado tracks the team investigated.

Many ground anchors pulled out of the soil because they were not deep enough. Many steel anchor shafts weren't strong enough to withstand lateral wind forces, leading to failures of the superstructure.

Ground anchors did not appear to comply with the requirements of Federal Manufactured Home Construction and Safety Standards, as revised in 1994.

Connections of strapping to chassis beams often came loose and were on the ground; there were no positive bolted or welded connections.

Galvanized steel strapping in several instances failed from uplift and overturning wind forces - or they became loose when the home moved laterally from wind forces.

Many of these kinds of damages - to homes, to businesses and even manufactured homes - are preventable.

Recommendations

Today, I am urging local officials in tornado areas to help their communities come through a tornado event by adopting, following and rigorously enforcing the latest model building codes and national consensus wind engineering standards.

I am urging local officials in tornado areas to take steps to ensure that manufactured homes are installed and secured properly.

I am urging insurance companies to offer lower rates to people who reduce their risks by securely anchoring their manufactured homes - or even better, put them on a permanent foundation.

Today, I am urging homeowners in tornado states to find out whether or not their homes meet the most recent model building codes and standards. And if not - I urge you, if it's at all possible, to upgrade your home to meet the newest standards. And if you can - go beyond the high wind requirements of the current model building codes.

It could save your home, and your life.

Have an inspector look at your garage door - especially if it is a double-wide door. Bring it up to or exceed the code.

If you have a masonry chimney that is higher than six feet above your roof -- retrofit with continuous vertical reinforcing steel in the corners to help resist high winds.

Make sure your door-frames are anchored strongly to the house. Double doors can be very dangerous in high winds if they are not securely fastened.

Make sure that the architectural features of you home are designed, manufactured and installed to limit the creation of wind-borne debris.

Today, I urge businesses in tornado areas to use construction techniques that have been perfected in coastal regions to limit hurricane damage.

Make sure your buildings meet or exceed current model building code requirements.

Make sure your garage doors comply with the latest national wind loads standards. Retrofit your existing garage doors to improve their resistance against high winds -- especially double-wide garage doors.

Before I conclude I want to touch on one other area.

Everything we discussed here today was about saving property.

If you are in the direct path of a violent tornado, the most important thing at that moment is to be in a well-built safe room or shelter.

When President Clinton and I toured the Oklahoma City area after those devastating tornadoes he and I discussed the need for "safe rooms" in each home.

In fact, the President said publicly that he believed the best investment people who live in Tornado Alley could make was to incorporate a safe room in the building or rebuilding of their home or business.

Business, homes, schools, hospitals and manufactured home communities must all have safe rooms or shelters.

You can save your life, your home, your business and your community.

Last Modified: Friday, 31-Oct-2003 09:25:25