Part 1 of a 5-part series
FRANKLIN COUNTY — Its Severe Weather Awareness Week in Pennsylvania and the National Weather Service wants to educate the public about different aspects of the term “severe” when it comes to weather.
Every day through Friday, NWS will tackle a different subject. Today’s is tornadoes.
While most tornadoes that occur in Pennsylvania are not as strong as their counterparts in the plains, strong and damaging tornadoes can and do occur here.
In fact, Pennsylvania ranks in the top 25 for tornado occurrence in the United States, averaging twenty tornadoes per year.
Between May 31st and June 2nd of 1998, Pennsylvania was hit by 40 tornadoes, some of which had wind speeds over 200 mph.
Definition of a Tornado
A tornado is a violently rotating column of air touching the ground, usually attached to the base of a thunderstorm.
Tornadoes are nature”s most violent storms. Spawned from powerful thunderstorms, tornadoes can cause fatalities and devastate a neighborhood in seconds.
Winds of a tornado may reach 300 miles per hour. Damage paths can be in excess of one mile wide and 50 miles long. Strong downburst (straight-line) winds may also occur due to the same thunderstorm.
Hail is commonly found very close to the tornadoes, as the strongest thunderstorms that spawn tornadoes are formed under the atmospheric conditions that are also highly likely to make hail.
Every state is at some risk from this hazard. Pennsylvania has its share, and they can happen at time of the year. The peak months are spring and summer, however.
Some tornadoes are clearly visible, while rain or nearby low-hanging clouds obscure others. Tornadoes develop extremely rapidly, and may dissipate just a quickly. Most tornadoes are on the ground for less than 15 minutes.
Before a tornado hits, the wind may die down and the air may become very still. A cloud of debris can mark the location of a tornado even if a funnel is not visible. Tornadoes generally occur near the trailing edge of a thunderstorm. It is not uncommon to see clear, sunlit skies behind a tornado.
The Difference Between a Tornado Watch and a Tornado Warning
A Tornado Watch is issued by the National Weather Service in order to alert you that severe thunderstorms are expected to develop. And to highlight that those storms have the potential to produce tornadoes.
A Tornado Watch covers a very wide area, generally about the size of a state. A Tornado Watch will last for several hours, expiring only when the threat of thunderstorms is expected to end.
What should you do when a Tornado Watch is issued? Go about your normal activities, but watch the sky around you for developing storms. Periodically listen to NOAA Weather Radio or media outlets for updates and possible warnings. Know which county you live in, and which ones border your community.
Think of a safe place to move to quickly if a tornado warning is issued for your location, or if thunderstorms approach.
A Tornado Warning is issued when meteorologists spot a developing tornado using Doppler radar, or when a tornado has been sighted by trained Skywarn spotters.
The warning means a tornado is going to move through your area soon, so you need to take immediate action to protect your life and property.
Tornado Warnings issued by National Weather Service meteorologists typically cover areas smaller than one county, and for a duration of generally less than one hour.
In the text of the warning statement, NWS tries to make a specific list of towns that are likely to be in the path of the tornado.
You should listen to hear if communities or landmarks near you are mentioned in the warning.
What You Should Do When a Tornado Warning Is Issued
Take immediate action, but remain calm. If you are at home or in a small building, go to the basement or to an interior room on the lowest floor.
Closets, bathrooms, and other interior rooms without windows offer the best protection. Avoid windows and get under something sturdy or cover yourself with a mattress.
If you are in a school, hospital, or shopping center, go to a pre-designated shelter area. Stay away from large open areas such as gyms or auditoriums.
Hallways and small interior rooms offer the best protection. Do not go outside to your car.
If you are in a high-rise building, go to an small interior room or hallway on the lowest floor possible. Do not use the elevator.
Mobile homes are easily tossed about by the strong winds of a tornado. Immediately take shelter in a substantial structure.
If you are caught outdoors and cannot get to a safe building, as a last resort, you should get in a vehicle if you have access to one. Buckle your seat belt and try to drive to the closest sturdy shelter.
If your vehicle is hit by flying debris while you are driving, pull over and park. Stay in the car with the seat belt on. Put your head down below the windows, cover your head with your hands and a blanket, coat or other cushion if possible.
If you can safely get noticeably lower than the level of the roadway, leave your car and lie in that low area, covering your head with your hands.
Your choice of whether to stay in your car should be driven by your specific circumstances. If you are in a car or if you seek shelter in a depression or ditch with a tornado approaching, you remain at risk.
The safest place to be is in an underground shelter, basement or safe interior room.
For additional information on tornadoes and severe weather check out NWS’ web site.
Come back to Franklin County Free Press tomorrow to lean about thunderstorm safety.