Severe Weather

Background:

Every year hundreds of people are injured or killed from severe weather, which includes severe thunderstorms, lightening and tornados. In many instances lives could be saved and serious injury avoided if there had been sufficient advanced warning and everyone knew the appropriate actions to take. A delay of as little as two minutes can literally mean the difference between life and death. The University of West Georgia already has a severe weather warning siren system in place, so the focus here is to detail the responses one should take when a siren sounds.

Tornados are the most severe of the weather-related events generated by thunderstorms; they can spawn at any time in a thunderstorm cell, they may appear very quickly and cause significant damage before they are even detected by such means as Doppler radar, etc. Once spawned, tornados can travel in any direction and can often out race the advancing storm front itself.

Clearly tornados are the chief concern in a severe weather episode; however, there are several other aspects of thunderstorms that you should consider. High velocity straight-line winds in excess of 58 miles per hour can overturn a mobile home that is not properly tied down. Wind speeds of 58 miles per hour and above cause thunderstorms to be classified as severe thunderstorms. High winds can break large limbs from trees and knock down power lines. Entire trees may be uprooted and fall. Hail may also be produced in sizes that can cause injury and serious property damage. Torrential rains may cause flash flooding in low-lying areas.

Lightening between the clouds and the ground can strike as far as ten miles in advance of a frontal system, well before it starts to rain. Similarly, lightening can strike as far as ten miles or more behind a passing frontal system, even after the heavy rains have already begun to subside. Persons who are exposed in open areas are potentially high-risk targets for lightening strikes. Golf courses produce the highest number of human lightening strikes in this country followed by boaters on open bodies of water. The expression “like a bolt out of the blue” has its basis in weather science.

Definitions:

Thunderstorm – Rainstorm accompanied by lightening and thunder.
Severe Thunderstorm – A thunderstorm having straight-line winds of 58 miles per hour or greater.
Funnel Cloud – A collection of winds spinning at high speeds in a circle or vortex.
Tornado – A funnel cloud making contact with the earth’s surface. Tornados are classified as to their size and power from F-0 to F-5, with F-5 being the most powerful and most devastating.

Watches And Warnings:

Watches are issued when the conditions are “right” for the production of a severe weather event. The National Weather Service normally issues watches for a period of six hours.

Warnings are issued when an actual severe weather event has been detected or sighted. The National Weather Service issues watches for a period of one hour. There is no “all clear” signal to cancel a watch. It automatically expires after one hour unless the siren has sounded again, then the one-hour clock is reset back to one hour. Warnings are frequently cancelled before the one-hour period has passed. This information can be obtained by listening to a local radio station. Generally calls to the local Emergency Management Agency or Police Department only serve to clog the telephone lines and prevent important information from being passed if there is damage or an emergency situation. Without reliable outside information, persons are advised to remain in sheltered areas for the full hour and then proceed out with caution, being especially cautious of falling materials and downed power lines.

Severe Thunder Storm Watch – Conditions are right for the formation of a severe thunderstorm (issued for six hours).
Severe Thunderstorm Warning – A severe thunderstorm has been detected and is posing an immediate threat to the surrounding area (in effect for one hour, unless the warning is re-issued, then an hour from the subsequent re-issuance).
Tornado Watch – Conditions are right for the formation of tornados (issued for six hours).
Tornado Warning – A tornado or funnel cloud has been sighted or detected in the immediate area. The siren will sound continuously for three minutes. Everyone should be in a sheltered area well before the siren has stopped sounding. This warning is issued for a period of one hour and will automatically self-cancel at the end of that period. However, a subsequent sounding of the siren will start a new one-hour period. Depending upon conditions, it is possible for there to be several siren soundings during a major severe thunderstorm event that is spawning multiple tornados.

It is important to take warnings seriously. When the siren sounds, there is a tornado in the area. It has been detected by radar or sighted visually often by members of a tornado spotters’ network. You may have less than two minutes to get to shelter! Seconds count, do not delay!

Actions To Take When The Siren Sounds

OUTSIDE - If you are outside, quickly enter the closest building and seek shelter in the safest part of the building (see the section “INSIDE,” below). If you are not near any buildings, lay down in any low area or any depression you can find.

MOTOR VEHICLE – If you are driving in a motor vehicle and you see a tornado or hear the warning siren, pull off of the road and get out of the vehicle. If there is a building nearby, try to get to the building as quickly a possible. If the tornado is overtaking you, lay down in any low area or any depression you can find.

MOBILE HOME – Do not remain in a mobile or manufactured home. Leave and proceed to a nearby building, if at all possible. If there is no building nearby and the tornado is approaching, lay down in any low area or any depression you can find.

INSIDE – Immediately proceed to the safest part of the building. To determine where this is, use the following guide:

Do not leave the building to go to another building!
Avoid glass doors and windows; don’t look for the tornado!
Go to the lowest level of the building.
Seek small, interior rooms that have no windows or outside walls. Avoid large rooms with open-span ceilings.
Try to have two walls between you and the outside.
Restrooms are usually good choices.
Avoid the Southwest portion of the building (most storms and tornados travel from Southwest to Northeast).
Note the time the siren sounded and remain in the shelter area for one hour or until the warning has been cancelled by the National Weather Service. If you have a radio, tune to a local station. Weather information will be passed by radio and television as it is released by the National Weather Service. If the warning is cancelled before it expires, this information will be announced over the radio and television. Do not use the telephone to call police or other emergency agencies. If there is damage, lines will need to be kept free for emergency calls.
If the siren is sounded again, note the time and remain in the shelter area for one hour. Each new warning is issued for an hour. This means another tornado has been detected.
If there is damage, be prepared to deal with fire and injuries. A loss of power may seriously reduce visibility.

After Warning Is Over:

You may proceed outside but do so with caution.
Avoid downed wires. Stay at least 25 feet from arcing power lines.
Look for limbs, building debris, etc. that could fall on you. Damaged buildings and trees may be on the verge of collapse.
Drive with care. Conditions may make driving extremely difficult. Roads may be littered with tree limbs, wires and other storm debris.
Do not drive across downed wires!
Give way to emergency vehicles.

Faculty & Staff Responsibilities:

Do not cancel class and send the students away.
Direct students to shelter areas and advise them to remain for one hour or until the warning is cancelled by the National Weather Service.
Advise them to use caution when leaving the shelter area after the warning has expired or has been cancelled.
After the warning has passed, classes may resume for the next period if there is no damage or disruption of power. In the event of damage, an evaluation will be made to determine what parts of the University can return to their normal routine.