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Tornado / Severe Weather


  • SEVERE THUNDERSTORM: Officially defined as storms that are capable of producing hail that is an inch or larger or wind gusts over 58 mph. Hail this size can damage property such as plants, roofs and vehicles. Wind this strong is able to break off large branches, knock over trees or cause structural damage to trees. Some severe thunderstorms can produce hail larger than softballs or winds over 100 mph. Thunderstorms also produce tornadoes and dangerous lightning; heavy rain can cause flash flooding.
  • FUNNEL CLOUD: A rotating, cone-shaped column of air extending downward from the base of a thunderstorm. When it reaches the ground, it is called a tornado.
  • TORNADO: A violently rotating column of air extending from the base of a thunderstorm down to the ground. Tornadoes are capable of completely destroying well-made structures, uprooting trees, and hurling objects through the air like deadly missiles. Tornadoes can occur at any time of day or night and at any time of the year. Although tornadoes are most common in the Central Plains and the southeastern United States, they have been reported in all 50 states. The Fujita Scale classifies tornados based on wind damage:
    • F0, 40 – 70 mph winds, light damage
    • F1, 73 – 112 mph winds, moderate damage
    • F2, 113 – 157 mph winds, considerable damage
    • F3, 158 – 206 mph winds, severe damage
    • F4, 207 – 260 mph winds, devastating damage
    • F5, 261 – 318 mph winds, incredible damage
  • WEATHER SIREN: Generally a continuous steady tone lasting 3 minutes or longer.  You generally will NOT receive an all clear via the siren, and just because it stops does NOT mean danger has passed.  Weather sirens are used for tornados, and some areas may also use them for severe storms.
  • SEVERE THUNDERSTORM WATCH: Severe thunderstorms are possible in and near the watch area. Stay informed and be ready to act if a severe thunderstorm warning is issued.
  • SEVERE THUNDERSTORM WARNING: Severe weather has been reported by spotters or indicated by radar. Warnings indicate imminent danger to life and property. Take shelter in a substantial building. Get out of mobile homes that can blow over in high winds.
  • TORNADO WATCH: Tornadoes are possible in and near the watch area. Be ready to act quickly if a warning is issued or you suspect a tornado is approaching.
  • TORNADO WARNING: A tornado has been sighted or indicated by weather radar. There is imminent danger to life and property. Move to an interior room on the lowest floor of a sturdy building. Avoid windows. If in a mobile home, a vehicle, or outdoors, move to the closest substantial shelter and protect yourself from flying debris.
  • HURRICANE WARNING: Hurricane conditions (sustained winds of 74 mph or greater) are expected somewhere within the specified area. NHC issues a hurricane warning 36 hours in advance of tropical storm-force winds to give you time to complete your preparations. Evacuate immediately if so ordered.
  • TROPICAL STORM WARNING: Tropical storm conditions (sustained winds of 39 to 73 mph) are expected within your area within 36 hours.
  • EXTREME WIND WARNING: Extreme sustained winds of a major hurricane (115 mph or greater), usually associated with the eyewall, are expected to begin within an hour. Take immediate shelter in the interior portion of a well-built structure.


  • Be weather-ready: Check the forecast regularly to see if you’re at risk for severe thunderstorms or tornadoes. Listen to local news or a NOAA Weather Radio to stay informed about severe thunderstorm or tornado watches and warnings.
  • Sign up for notifications: UIU utilizes the UIU Alert system in the event of an emergency.  Many communities also have outdoor sirens and deliver alerts to smart phones.
  • Know where you will go.  Signage is posted in UIU buildings indicating where to go in severe weather.  You will generally be directed to the innermost location of the building on the lowest floor, ideally one with no windows or outside doors.
  • Help Your Neighbor: Encourage others to prepare for the possibility of severe thunderstorms and tornadoes.

In an Emergency

  • Stay weather-ready: Continue to listen to local news or a NOAA Weather Radio to stay updated about severe thunderstorm or tornado watches and warnings. UIU utilizes the UIU Alert system in the event of an emergency.
  • At your UIU location: Stay away from windows if you are in a severe thunderstorm warning and damaging wind or large hail is approaching. If a tornado siren sounds, a tornado warning is issued, or you have other reason to believe a tornado may be in the area, proceed to your tornado shelter location quickly and calmly. If you cannot get to a designated shelter area, go to an interior room or hallway on the lowest level of the building, away from doors and windows, and sit as low to the ground as possible. Protect your head. Stay away from large open rooms, such as cafeterias, gymnasiums, or auditoriums.
  • At your house: Go to your secure location if you hear a severe thunderstorm warning. 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.
  • Outside: Seek shelter inside a sturdy building immediately if severe thunderstorms or a tornado are approaching. Sheds, storage facilities, tents, and shelter under a tree are not safe. If you have time, get to a safe building.
  • In a vehicle: Being in a vehicle during severe thunderstorms is safer than being outside; however, drive to closest secure shelter if there is sufficient time. Being in a vehicle during a tornado is not safe. The best course of action is to drive to the closest 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.
  • Follow directions of emergency responders where applicable.