Tornado safety and resilience for businesses

Whether in person or only via television news reports, we have all seen the aftermath of the devastating power of tornadoes: leveled buildings and homes, trees toppled, vehicles upturned, debris scattered and — in the worst cases — lives lost. Tornadoes are among the most violent and destructive storms we experience, with wind speeds that can go higher than 200 miles per hour and recorded damage paths up to one mile in width and up to 50 miles in length.

Adding to worries for businesses is that a tornado doesn’t have to come close to maximum severity to do potentially serious harm to your operations. Even if your company’s property goes untouched, a long-lasting power outage can impact communications with customers, vendors and suppliers. Or if area streets and highways are closed due to storm damage, your fleet may be delayed for days in getting shipments out.

The average number of tornadoes in the U.S. has been fairly consistent over the last 30 years. According to data specialists Statista, the nation averaged over 1,200 tornadoes each of the first 21 years of this century¹ and NOAA's National Centers for Environmental Information shows a similar average from 1991 through 2010.²

That’s a lot of tornadoes. And while businesses in tornado-prone regions need to be most aware of their risks, tornadoes and derechos in big cities like Washington, D.C. and Chicago show these types of storms are not restricted to lower-population areas or the Great Plains. They can occur anywhere in the world and develop very quickly, so every business needs an Emergency Response Plan (ERP) for tornadoes.

What causes tornadoes?

The NOAA’s National Severe Storms Laboratory defines a tornado as “a narrow, violently rotating column of air that extends from a thunderstorm to the ground.”³  They are spawned by collisions of warm, wet air masses with cool, dry ones. Of course, not all thunderstorms lead to tornadoes. What makes twisters particularly menacing is that they form quickly, with little warning. Summer is peak tornado season, but they can occur any time of the year … even during winter.

What is an Emergency Response Plan for tornadoes?

As with most ERPs for natural hazards, a company’s ERP for tornadoes can be divided into four phases: mitigation, preparedness, response and recovery. The plan should be developed with risk specialists and communicated to all employees, with response plan actions assigned as needed to specific teams or workers. Make sure the ERP is in writing and easily accessible. Required testing and training related to the ERP is also a good precaution to ensure your people are ready if and when a tornado strikes.

1. How can you mitigate tornado risks?

This is the ongoing work to keep your people and property as shielded from the impacts of a tornado as possible. Mitigation can range from long-term, high-investment work on building structures to much simpler, low- or no-cost steps. Your ERP should include these mitigation actions:

• Have architectural/engineering evaluations of your existing property performed.
• Upgrade existing structures as needed based on those evaluations.
• For new construction, work with an architect or contractor to incorporate wind-mitigation techniques and high wind-rated products.
• If possible, have a thoroughly tornado-proofed shelter or “safe room” installed near or inside your business property. There are three basic types:

Underground shelters – Constructed from reinforced steel or concrete and typically installed near a structure, these are designed for maximum survivability during a tornado. They protect those inside from falling or flying debris that still could be a threat in a basement. Underground shelters should be situated close enough to your building to be quickly and readily accessible during already difficult weather conditions, as when a tornadic storm may be approaching.

Shelters built into the facility – If ground conditions such as high local water tables or the likelihood of flooding preclude underground shelters, a suitable alternative can be a safe room built inside a facility during initial construction or renovation. Constructed of reinforced concrete or steel, these should be self-contained and firmly anchored to the foundation to prevent overturning or dislodging during a storm.

Prebuilt shelters – If the first two options are impractical, manufacturers of pre-built shelters can provide installations made from sturdy steel frames and panels that can be retrofitted into existing structures. Once again, the shelter must be firmly anchored to the building’s foundation for maximum effectiveness.

• Situate network servers and other vital equipment in protected areas of a building, preferably in tornado-resistant rooms.
• Have a well-maintained and fueled generator to supply your facility with emergency power during an outage.
• Review your current insurance coverages to ensure they reflect your exposures.

2. How should you prepare for potential tornado impacts?

These preparation steps need to be in place before any storm is imminent.

Preparing your people

• Identify the safest areas in a building for people to shelter in the event of a tornado warning. If you do not have a specially designed safe room as described in the mitigation section above, this safest area will often be in the basement or the level that is the lowest point in your building.
• Post signs in buildings to direct employees, customers and visitors to safe areas.
• Designate roles and responsibilities of supervisors and employees, including the appointment of tornado wardens.
• Practice your sheltering plan so you know how long it takes to move everyone to safety. The average warning time is 13 minutes, but tornadoes are unpredictable.
• Practice an evacuation plan for the potential of authorities putting evacuation orders into effect.
• Stay informed by keeping tabs on official warnings issued by the National Weather Service (and consider purchasing an NOAA Weather Radio with a tone alert feature), and local TV and radio weather broadcasts.
• Be aware of changing weather conditions around you, such as darkening skies; high, gusty winds; low-lying clouds; sharply defined front lines and wall clouds; and hail.

Preparing your property

If an official tornado watch is in effect, or if there has been enough volatile weather to indicate one might go into effect soon, the following actions are recommended:

• Remove and secure outdoor gear and small equipment.
• Secure outbuildings to prevent them from becoming airborne missiles.
• Remove or secure any construction scaffolding.
• Reinforce any vulnerable areas of a building, such as  building openings.
• Stock up on emergency supplies, including: Flashlights and batteries, drinking water, First Aid kits.

Preparing for business continuity

As mentioned near the start of this article, whether your business experiences severe property damage or not, operational and/or supply chain interruptions can occur in the aftermath of a tornado. These steps can help make sure your business is prepared to forge ahead with the response and recovery phases of your ERP:

• Plan for communication among employees and management if your facility experiences significant damage, such as dedicated channels for cell phone calls and text messaging via mobile devices. Cell towers can also be damaged during tornadoes, however, so it can be prudent to have non-cellular wireless devices, or so-called “walkie-talkies,” ready as backups.
• Work with your company’s IT and cyber specialists on back-ups and restoration plans for data and information technology.
• Determine how supply chain logistics will be maintained or restored as needed.
• If possible, plan to move manufacturing and other critical business operations to other facilities until a damaged building is repaired or replaced.

3. How should  you respond when a tornado is imminent or active?

If a tornado warning is in effect or it is clear a threat is imminent, the first priority must be keeping people safe. Most injuries and deaths during tornadoes are caused by flying debris from structural damage, so these three precautions are key:

• Take shelter – Ensure all employees, customers and visitors are inside. If employees are on an outdoor job site, in a vehicle or unable to get to the company’s best-protected property, they should get to the nearest substantial structure as quickly as possible. Remaining outside, exposed to wind-driven debris is a recipe for disaster.
• Stay low – Once inside, all employees, customers and visitors should move to the shelter area designated during the preparation phase of your ERP. If a safe room, basement or lowest-level shelter is not accessible, move people to an internal hallway with best structural integrity to withstand tornado-force winds. Move everyone away from all windows, doors and other openings.
• Take cover – All building occupants should take cover underneath anything that may provide increased protection — a table, desk, pillows, a mattress or whatever can safely come between you and airborne debris. Have occupants wear hardhats and other protective gear if available.

4. What are the key recovery actions to take after a tornado?

Even when the skies have cleared, safety has to be job number one as your business works to recover following a tornado. Management, employees and all other occupants of the building need to be cognizant of multiple hazards that can be created from the effects of tornado damage. Similarly, off-site employees must be informed when the property and surrounding region is safe for them to return to the workplace. There are two key components for safe recovery efforts: communication and caution.

Communication

• The preparation phase of an ERP includes planning for emergency communication channels. If there are power outages, downed telephone lines or damage to buildings that people need to be alerted to, now is the time to use those channels — cell phone calls, “walkie-talkies,” texting, email, etc. — to pass information about current conditions.
• Notify local media outlets of conditions so they might broadcast that information, hopefully reaching anyone who might be away from the area who is planning to return to it before conditions are safe.

Caution

For those inside the building:

• If the building you are occupying was damaged, use extreme care when exiting.
• If you smell gas or sense flammable liquids may be present, do not use an open flame, such as matches or  cigarette lighters.
• Anyone trapped should remain calm and text or call for help. If possible, bang on a wall or exposed pipe to attract attention.

For those outside the building:

• Do not enter any damaged structures until they are deemed structurally stable by first responders.
• Watch for, avoid and report downed power lines.
• During cleanup in the days following the storm, use care when using chainsaws and removing debris.
• Wear appropriate footwear and gloves to protect against sharp edges, exposed nails and other hazards.

With a proper tornado Emergency Response Plan in place, your business will be better prepared to avoid the most severe consequences of these very common and dangerous storms, or at least be in a strong position to respond and recover more quickly from the damage they inflict. Good business planning means good resilience planning. Make this ERP a part of it.

Tornadoes are not the only severe weather threat that could affect your business and property. Here are additional articles offering insights on how to help mitigate, respond to and recover from these events:

Visit the Convective Storm Resource Hub for additional articles offering insights on how to help mitigate, respond to and recover from lightning strikes, hailstorms and convective storms.

1. “Number of tornadoes in the United States from 1995 to 2020.” Statista. 2020.

2. National Oceanic and Atmospheric Administration/National Centers for Environmental Information. U.S. Tornado Climatology page. Accessed 26 July 2021.

3. National Oceanic and Atmospheric Administration/ National Severe Storms Laboratory. “Severe Weather 101: Tornado Basics.” Accessed 26 July 2021.