With storm season already in progress, now is the time to become aware of tornado safety and preparation. While Pennsylvania doesn’t get as many tornadoes as tornado alley does, we still have tornadoes spin up every now and again. Here is what you need to know about safety and preparation.
To start, what exactly is a tornado? A tornado is a narrow, violently rotating column of air that extends from the base of a thunderstorm to the ground. Because wind is invisible, it is hard to see a tornado unless it forms a condensation funnel made up of water droplets, dust and debris. Tornadoes are the most violent of all atmospheric storms. How does a tornado form? The truth is that we don’t fully understand. The most destructive and deadly tornadoes occur from supercells, which are rotating thunderstorms with a well-defined radar circulation called a mesocyclone. (Supercells can also produce damaging hail, severe non-tornadic winds, unusually frequent lightning, and flash floods.) Tornado formation is believed to be dictated mainly by things which happen on the storm scale, in and around the mesocyclone.
How common are tornadoes, and how many form each year? About 1,200 tornadoes hit the U.S. yearly. Since official tornado records only date back to 1950, we do not know the actual average number of tornadoes that occur each year. Plus, tornado spotting and reporting methods have changed a lot over the last several decades.
What exactly is tornado season? Tornado season usually refers to the time of year the U.S. sees the most tornadoes. The peak “tornado season” for the Southern Plains is during May into early June. On the Gulf coast, it is earlier during the spring. In the northern plains and upper Midwest, tornado season is in June or July. But, remember, tornadoes can happen at any time of year.
Now that we covered the general tornado information (how it forms, how many, and where/when), we will talk about the difference between a watch and a warning. So, what exactly is a tornado WATCH and a WARNING? A Tornado WATCH is issued by the NOAA Storm Prediction Center meteorologists who watch the weather 24/7 across the entire U.S. for weather conditions that are favorable for tornadoes. A watch can cover parts of a state or several states. Watch and prepare for severe weather and stay tuned to NOAA Weather Radio to know when warnings are issued. A Tornado WARNING is issued by your local NOAA National Weather Service Forecast Office meteorologists who watch the weather 24/7 over a designated area. This means a tornado has been reported by spotters or indicated by radar and there is a serious threat to life and property to those in the path of the tornado. ACT now to find safe shelter! A warning can cover parts of counties or several counties in the path of danger.
It is also important to have a plan of action in case of a severe storm or a tornado. Here are some things to do, to prepare for a tornado:
Identifying Shelter Locations
An underground area, such as a basement or storm cellar, provides the best protection from a tornado. If an underground shelter is unavailable, consider the following:
- Seek a small interior room or hallway on the lowest floor possible
- Stay away from doors, windows, and outside walls
- Stay in the center of the room, and avoid corners because they attract debris
- Rooms constructed with reinforced concrete, brick or block with no windows and a heavy concrete floor or roof system overhead
- Avoid auditoriums, cafeterias and gymnasiums that have flat, wide-span roofs.
Personnel should also be aware of what to do if caught outdoors when a tornado is threatening. Seek shelter in a basement or a sturdy building. If one is not within walking distance, try to drive in a vehicle, using a seat belt, to the nearest shelter. If flying debris is encountered while in a vehicle, there are two options: 1) staying in the vehicle with the seat belt on, keeping your head below the windows and covering it with your hands or a blanket, 2) if there is an area which is noticeable lower than the roadway, lie in that area and cover your head with your hands.
The following steps are recommended to help ensure the safety of personnel if a tornado occurs:
- Develop a system for knowing who is in the building in the event of an emergency
- Establish an alarm system to warn workers
- Test systems frequently
- Develop plans to communicate warnings to personnel with disabilities or who do not speak English
- Account for workers, visitors, and customers as they arrive in the shelter
- Use a prepared roster or checklist
- Take a head count
- Assign specific duties to workers in advance; create checklists for each specific responsibility. Designate and train workers alternates in case the assigned person is not there or is injured
Some businesses are required to have an Emergency Action Plan meeting the requirements under 29 CFR 1910.38, see Evacuation Plans and Procedures eTool for more information. Though Emergency Action Plans primarily involve evacuations, emergency planning for tornadoes involve identifying safe places of refuge for workers to go to in the event of tornadoes.
- Get emergency supply kits and keep them in shelter locations
- Basic Disaster Supplies Kit
- Learn more about NOAA Weather Radio, at NOAA’s website.
Training and Exercises
- Ensure that all workers know what to do in case of an emergency.
- Practice shelter-in-place plans on a regular basis.
- Update plans and procedures based on lessons learned from exercises.
For more information, see the preparedness guide developed by NOAA, FEMA and the American Red Cross.