National Weather Service United States Department of Commerce

Tornado Safety

It is important to have a plan of action in the event a tornado threatens your family, and to rehearse that plan frequently. Such a plan should include what you and your family should do when at home, work, school, or outdoors. The time spent planning now could determine whether or not you survive a tornado.

Plan Ahead

First, know the county in which you live. Severe weather warnings are issued for counties, or for portions of counties. By keeping a highway roadmap nearby, you can follow storm movements, and better determine if you are threatened.

The links below will help you find out what you can do now to prepare for a tornado. Preparation is key to staying safe and minimizing impacts.

  • Be Weather-Ready: Check the forecast regularly to see if you're at risk for tornadoes. Listen to local news or a NOAA Weather Radio to stay informed about tornado watches and warnings. Check the Weather-Ready Nation for tips.
  • Sign Up for Notifications: Know how your community sends warnings. Some communities have outdoor sirens. Others depend on media and smart phones to alert residents of severe storms capable of producing tornadoes.
  • Create a Communications Plan: Have a family plan that includes an emergency meeting place and related information. If you live in a mobile home or home without a basement, identify a nearby safe building you can get too quickly, such as a church or family member.
  • Pick a safe room in your home, such as a basement, storm cellar, or an interior room on the lowest floor with no windows. Check more ideas for your family plan at: https://www.ready.gov/make-a-plan
  • Practice Your Plan: Conduct a family severe thunderstorm drill regularly so everyone knows what to do if a tornado is approaching. Make sure all members of your family know to go there when tornado warnings are issued. Don't forget pets if time allows.
  • Prepare Your Home: Consider having your safe room reinforced. You can find plans for reinforcing an interior room to provide better protection on the Federal Emergency Management Agency website.
  • Help Your Neighbor: Encourage your loved ones to prepare for the possibility of tornadoes. Take CPR training so you can help if someone is hurt.

** If you see a tornado, or hear that the National Weather Service has issued a Tornado Warning for your location... **

Know Where to Go and What to Do

Find out what you can do when a tornado strikes. Acting quickly is key to staying safe and minimizing impacts.

  • Stay Weather-Ready: Continue to listen to local news or a NOAA Weather Radio to stay updated about tornado watches and warnings.
  • Read or listen to the text of a Tornado Warning from the NWS:  The locations (counties, towns) that are most at-risk from the potential or actual tornado will be listed. There is very important information contained in the text of the warning - including where, when and what to expect. It will also detail some safety actions you may take to keep yourself and family/friends/neighbors safe. Some of our safety tips follow:
  • At Your House: If you are in a tornado warning, go to your basement, safe room, or an interior room away from windows. Don't forget pets if time allows.
  • At Your Workplace or School: Follow your tornado drill and proceed to your tornado shelter location quickly and calmly. Stay away from windows and do not go to large open rooms such as cafeterias, gymnasiums, or auditoriums.
  • Do not open windows! This is a mistake - it will only serve to allow strong winds to enter your home and perhaps cause more damage.
  • Outside: Seek shelter inside a sturdy building immediately if a tornado is approaching. Sheds and storage facilities are not safe. Neither is a mobile home or tent.  If you have time, get to a safe building.
  • In a vehicle: Being in a vehicle during a tornado is not safe. The best course of action is to drive to the closest permanent shelter. If you are unable to make it to a safe shelter, either get down in your car and cover your head, or abandon your car and seek shelter in a low lying area such as a ditch or ravine. Do not seek shelter under a highway overpass! That has been proven to be more dangerous than lying flat in a ditch. 

General Tornado Info

Frequently Asked Tornado Questions (link to the NWS Storm Prediction Center).

Local Tornado Historical Climatology

Here is a link to a fantastic page we have about previous tornadoes and tornado statistics for Pennsylvania.

A few statistics follow below:

Central PA Tornadoes by County through 2010

 

PA Tornadoes by Month:

 

The Enhanced Fujita Scale
(EF Scale)

How we rate the strength of the winds in a tornado


The EF Scale, which became operational on February 1, 2007, is used to assign a tornado a 'rating' based on estimated wind speeds and related damage. When tornado-related damage is surveyed, it is compared to a list of Damage Indicators (DIs) and Degrees of Damage (DoD) which help estimate better the range of wind speeds the tornado likely produced. From that, a rating (from EF0 to EF5) is assigned.

The EF Scale was revised from the original Fujita Scale to reflect better examinations of tornado damage surveys so as to align wind speeds more closely with associated storm damage. The new scale has to do with how most structures are designed.


EF SCALE
EF Rating 3 Second Gust (mph)
0 65-85
1 86-110
2 111-135
3 136-165
4 166-200
5 Over 200

*** IMPORTANT NOTE ABOUT EF SCALE WINDS: The EF scale still is a set of wind estimates (not measurements) based on damage. Its uses three-second gusts estimated at the point of damage based on a judgment of 8 levels of damage to the 28 indicators listed below. These estimates vary with height and exposure. Important: The 3 second gust is not the same wind as in standard surface observations. Standard measurements are taken by weather stations in open exposures, using a directly measured, "one minute mile" speed.


Assigning a Tornado Rating Using the EF Scale

The NWS is the only federal agency with authority to provide 'official' tornado EF Scale ratings. The goal is assign an EF Scale category based on the highest wind speed that occurred within the damage path. First, trained NWS personnel will identify the appropriate damage indicator (DI) [see list below] from more than one of the 28 used in rating the damage. The construction or description of a building should match the DI being considered, and the observed damage should match one of the 8 degrees of damage (DOD) used by the scale. The tornado evaluator will then make a judgment within the range of upper and lower bound wind speeds, as to whether the wind speed to cause the damage is higher or lower than the expected value for the particular DOD. This is done for several structures not just one, before a final EF rating is determined.


Enhanced F Scale Damage Indicators

NUMBER
(Details Linked)
DAMAGE INDICATOR ABBREVIATION
1 Small barns, farm outbuildings SBO
2 One- or two-family residences FR12
3 Single-wide mobile home (MHSW) MHSW
4 Double-wide mobile home MHDW
5 Apt, condo, townhouse (3 stories or less) ACT
6 Motel M
7 Masonry apt. or motel MAM
8 Small retail bldg. (fast food) SRB
9 Small professional (doctor office, branch bank) SPB
10 Strip mall SM
11 Large shopping mall LSM
12 Large, isolated ("big box") retail bldg. LIRB
13 Automobile showroom ASR
14 Automotive service building ASB
15 School - 1-story elementary (interior or exterior halls) ES
16 School - jr. or sr. high school JHSH
17 Low-rise (1-4 story) bldg. LRB
18 Mid-rise (5-20 story) bldg. MRB
19 High-rise (over 20 stories) HRB
20 Institutional bldg. (hospital, govt. or university) IB
21 Metal building system MBS
22 Service station canopy SSC
23 Warehouse (tilt-up walls or heavy timber) WHB
24 Transmission line tower TLT
25 Free-standing tower FST
26 Free standing pole (light, flag, luminary) FSP
27 Tree - hardwood TH
28 Tree - softwood TS
Other background information: