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Thunderstorms/Tornadoes

A tornado is defined as a violent rotating column of air extending from a thunderstorm to the ground, often formed when warm and cold air masses clash.  They are capable of tremendous destruction, creating damage paths in excess of one mile wide and 50 miles long.  Tornadoes’ speed can vary from nearly stationary to up to 70 mph; however, the wind speed from these formations can exceed 250 mph.

Tornadoes are classified using the Enhanced Fugita Scale. Most tornadoes (approximately 88 percent, are considered weak (F0 or F1) and about 95 percent of all U.S. tornadoes are below F3 intensity.

From 1996 through 2010, Arkansas averaged 60 tornado events per year; therefore, the probability that Arkansas will experience a tornado event is “highly likely”.

Thunderstorms and lightening occur in every region of Arkansas.  Thunderstorms are responsible for significant structural damage to buildings, forest and wildfires, downed power lines and trees, and flash flooding.  In Arkansas, an average of 168 severe storm events occur per year, along with 21 deaths, 215 injuries, and $50 million in property damage.  Hail usually occurs during severe thunderstorms, which also produce frequent lightning, flash flooding and strong winds, with the potential for tornadoes.

Key Points:

  • Severe weather such as thunderstorms and tornadoes can occur at any time
  • Strong winds, hail, and lightening often will accompany severe weather.
  • Severe weather can uproot trees and knock down utility poles, and blow down buildings
  • Lightening can strike causing fires, electrocution, and damage to equipment
  • Severe weather can last for hours
  • Extremely high winds, flying debris, as well as the debris left behind can cause personal injury or possible death
  • Tornadoes are unpredictable and can cause major damage and destruction in seconds.
  • Outdoor warning systems may not always be heard in all areas.

Watches and Warnings

THUNDERSTORM WARNING – A severe thunderstorm warning is issued when either trained storm spotters or Doppler weather radar report or indicate that a thunderstorm is producing or will soon produce dangerously large hail or high winds, capable of causing significant damage.

TORNADO WATCH – A tornado watch is issued when atmospheric conditions are favorable for the development of tornadoes in and close to the watch area.  Tornado watches are normally issued well in advance of the actual occurrence of severe weather.  During the watch period, people should review tornado safety rules/procedures and be prepared to move to a place of safety if threatening weather approaches.  Under watch conditions stay informed by listening to radio or television.

TORNADO WARNING – A tornado warning is issued when a tornado or funnel cloud is indicated by Doppler weather radar or sighted by spotters.  People in the affected area should seek safe shelter immediately.  A tornado warning indicates a tornado is imminent.  If the warning is for your area you should take shelter immediately.

TAKE ACTION

Before the Storm

  • Review actions to take should the situation change to a Tornado Warning, or if a tornado funnel is sited or radar-indicated.
  • Locate a basement or corridor shelter in your building.
  • Stay informed through local media sources.
  • Keep a good reliable flashlight in your office/work area.

During the Storm – Possible Indicators of a Tornado

  • Dark, often greenish sky
  • Large hail
  • Loud roar, similar to a train
  • Cloud of debris (the tornado may not be visible)
  • Wind suddenly becomes calm and still
  • Frequent lightning
  • Tornadoes generally occur near the trailing edge of a storm

During the Storm – When Taking Shelter

  • Vacate upper floors and move to a lower floor or to the basement of any building that has a basement. (Safe locations have been posted in every building on campus.)
  • Occupants of wood-framed or brick buildings with wood floors should leave the building and go directly to a more substantial concrete building, preferably with a basement.
  • When possible, avoid auditoriums, gymnasiums, dining rooms, large lounges or other rooms with long roof spans and few supporting beams.
  • Avoid corridors that may become wind tunnels. These are corridors with exterior doors allowing direct exit outside.
  • Avoid spaces opposite doorways or openings into rooms that have windows in the exterior walls, particularly those facing south or west.
  • Avoid interior locations that contain windows such as display cases, transoms above doors and door skylights.
  • Do not use building elevators, electrical power failure may occur.
  • Assume a seated position on the floor with the head down and hands locked over the head during the storm period. If you are wearing a heavy jacket or have access to other heavy cloth material, use these items to cover your upper body and head. This will help to protect you from flying glass or debris. Always try to stay close to the floor.

Severe Weather Alerts at UCA

Upon the issuance by the National Weather Service of a tornado warning, and the warned area includes the UCA campus, the UCAAlert system will automatically alert the entire campus community via text, voice, and email messages.  Additionally, alert messages will be posted on Facebook and Twitter and outdoor tornado warning sirens* will be activated.

*Testing of UCA’s outdoor warning siren system occurs at 11:50 AM on the first Wednesday of each month except during periods of adverse weather conditions.