|
WEATHER SAFETY
(from NWS Birmingham's "Severe Weather Week" series of Public Information bulletins with some editing)
------------------------------------------------------------------------------------------
SEVERE THUNDERSTORMS
Thunderstorms are a common occurrence in Alabama during any time of the day, month, or year. There are about 2000 thunderstorms in progress around the world at any given moment. However, less than one percent of these classified as severe. Severe Thunderstorms are defined as those that produce hail three quarters of an inch or larger and strong wind gusts to 58 MPH or greater.
All thunderstorms generate potentially deadly lightning. However, lightning in a thunderstorm does not necessarily mean that the thunderstorm is severe. Ocassionally, a small percentage of severe thunderstorms produce tornadoes with little or no advance warning.
THUNDERSTORM SAFETY RULES
The best defense against thunderstorms is to stay inside a sturdy, substantial building that can sustain high winds. If caught outside, find shelter imediately. Thunderstorms typically last no more than an hour. Stay away from windows and avoid electrical equipment. Be sure to secure loose objects outside as these objects often become dangerous flying debris in high winds.
A SEVERE THUNDERSTORM WATCH means that conditions are favorable for severe thunderstorms to develop within the next few hours. People located in and around the watch area should keep an eye on the sky and listen to your NOAA weather radio or local broadcast media for further weather information.
A SEVERE THUNDER STORM WARNING means that either a severe thunderstorm is occurring, has been detected by radar, or has been reported to the NWS office by our storm spotters, local law enforcement, or emergency management agencies. When a SEVERE THUNDERSTORM WARNING is issued for your county, treat it the same as you would for a tornado warning by taking the proper safety precautions. Severe thunderstorms can produce strong damaging winds, large hail, lightning, and possible tornadoes.
-----------------------------------------------------------------------------------
LIGHTNING
The summer months of June through September are by far the most active months for lightning strikes. As many as one thousand lightning strikes have occurred in a five minute time period in one supercell thunderstorm over central Alabama.
Lightning research has shown that consecutive lightning strikes can occur as much as six miles apart. People often don't perceive lightning to be close if it is more than two miles away. However, the actual risk of the next strike being at your location is very high. Many lightning casualties occur during the beginning of a thunderstorm because people ignore these precursors. When thunderstorms are in the area but not directly overhead, the lightning threat can still exist even if it is sunny.
LIGHTNING SAFETY RULES
If you are caught outside, move into a well constructed home, large enclosed building, or an all metal vehicle. Once inside, do not use electrical appliances including telephones and stay away from windows.
If you are in a boat, get out of the water immediately and seek shelter in a substantial building or all metal vehicle. If you are caught in an open metal boat and cannot seek refuge from an approaching storm, lie down in the boat with the cushions between you and the metal sides and bottom.
If caught outdoors, crouch down and cover your head with your hands to avoid being the highest point for a lightning discharge. Remember to avoid lone trees and the tallest trees. If caught in the woods, pick a small grove of trees as your shelter and stand at least five feet from the trunk of the nearest tree to avoid flying bark if the tree is struck. If you are caught in a flat, open field or if you feel your hair standing on end, you could potentially be struck by lightning within a few seconds.
You should move away from motorcycles, scooters, golf carts, bicycles, tractors, and other metal farm equipment. Avoid wire fences, clotheslines, metal pipes, railroad tracks, and any other metallic items.
Remember there is no truth to the old myth that lightning never strikes the same place twice.
Practice the 30 30 rule. It could save your life. The first 30 means that you need to take cover if you hear thunder within 30 seconds of the lightning flash. The second 30 means that you should wait at least 30 minutes after the last flash or thunder in order to resume normal activity.
------------------------------------------------------------------------------
TORNADO
The Spring months of March through May are known as the Spring Tornado season. A fall Tornado Season also exists during the months of November through mid December. Alabama is one of the few locations in the world that has two distinct severe weather seasons. A Tornado is defined as a violently rotating column of air in contact with the ground. If the ciculation is not on the ground, then it is definded as a fullen cloud. Tornadoes usually descend from thunderstorms. Wind speeds in Tornadoes range from 40 MPH to around 318 MPH in the most violent of storms.
A TORNADO WATCH means that conditions are favorable for Tornadoes to develop within the next few hours. People located in and around the watch area should keep an eye on the sky and listen to your NOAA weather radio or local broadcast media for further weather information. A TORNADO WATCH is normally issued for a large area covering several counties. The WATCH is intended to give you time to prepare, and to review your safety rules. The sky may be sunny, but weather changes very quickly.
A TORNADO WARNING is issued when a developing tornado has been detected by radar or has been reported on the ground. A TORNADO WARNING is typically issued for only one or two counties at a time and usually lasts no more than 45 minutes. If a TORNADO WARNING is issued for your County, you should seek shelter immediately. If you see a Tornado or feel threatened, move to a safe place immediately as precious seconds can save your life.
TORNADO SAFETY RULES
If you are in a home or small business, go to the basement or to a small interior room such as a closet, bathroom, or interior hallway without windows on the lowest level. Put as many walls between you and the outside as possible. Be sure to get under something sturdy such as a heavy table or mattress to protect yourself from flying debris. Most injuries associated with high winds are from flying debris. Remember to protech your head. If available, put on a bicycle or motorcycle helmet to protect yourself from head injuries.
If you are in a large business, school, hospital, shopping center, or factory, go to the disignated shalter area. If a shelter area is not available, go to an interior hallway on the lowest level. Stay away from the structurally weather portions of buildings such as windows and rooms with expansive roof areas which are more lickely to collapse when Tornadoes strike. Don't waste time opening windows in an attempt to prevent damage. The old belief that damage could result from rapid pressure changes during a Tornado is not true. It will not make any difference if a window is open or not. Your safest course of action is to take shelter immediately when a TORNADO WARNING is issued for your area.
If you are in a mobile home or vehicle, get out and take shelter in a sturdy building. If there is not a building nearby, get to a low spot and cover your head to protect from flying debris. DO NOT take cover under an overpass as this DOES NOT provide adequate shelter during a Tornado.
----------------------------------------------------------------------------
FLOOD AND FLASH FLOOD
Alabama falls victim to Floods and Flash Floods every year. General river flooding occurs seasonally when Winter or Spring rains, or torrential rains associated with tropical systems, fill river basins too quickly. Flash Floods occur seddenly and usually within hours of excessive localized heavy rainfall. These Flash Floods can become raging torrents which rip through neighborhoods, streets, or valleys destroying everything in their path.
When Flash Flooding is anticipated, a FLOOD WATCH will be issued to emphasize the risk. This means that it is possible that heavy rains may cause Flash Flooding in and around a specified area. Stay weather alert by listening to your NOAA weather radio or local broadcast media for further weather updates. This is the time to start thinking about your plan of action if water begins to rise or a FLASH FLOOD WARNING is issued.
When a FLASH FLOOD WARNING is issued for your County, you must act quickly because these floods are an imminent threat to you and your family. You may only have seconds to move to higher ground.
FLASH FLOOD SAFETY RULES
During periods of heavy rains, stay away from known flood areas such as streams, dranage ditches and culverts. Move to high ground. Heavy rains should be signal to alert you to the possibility of dangerous flood conditions. If you live or work in known flood prone areas, remain especially alert during periods of heavy rain.
Never drive your car into water of unknown depth. Most Flash Flood deaths occur when people drive their vehicles into flood waters. Just remember the saying "Turn around, Don't drown". If your vehicle stalls, abandon it immediately to seek high ground. Flood water can rise very quickly; high enough to float, sink or carry away your vehicle. Be expecially cautious at night because it is harder to recognize flood dangers.
Stay out of flooded areas. Water may still be rising and is usually very swift. A rapidly flowing stream or ditch can sweep you off your feet or your car downstream. Children are especially vulnerable and should not be allowed to play in and around flowing water. Water can also run off strees and parking lots very rapidly causing natural and man made drainage systems to quickly overflow with rushing flood waters. These are very dangerous. They carry rocks, trees, trash and other type of debris that can be deadly to anyone in their path. Water is a very powerful force and shouold never be underestimated.
----------------------------------------------------------------------------------
NOAA WEATHER RADIO AND THE EMERGENCY ALERT SYSTEM
NOAA Weather Radio is commonly known as the voice of the National Weather Service. This broadcast system provides updated weather information 24 hours a day, every day of the year. NWS personnel prepare weather information that is normally broadcast in three to five minute cycles. This information includes forecasts, warnings, current conditions, climate data and other important weather information.
To receive NOAA weather radio broadcasts, a special radio capable of receiving signals in the Very High Frequency band, also known as VHF Public Service Band, is required. In Alabama, frequencies from 162.400 to 162.550 MHz are used. Alabama is served by 29 transmitters covering approximately 95 percent of the citizens in the State. (Residents of Lee County have two NOAA Weather transmitters in close proximity: 162.525 MHz in Auburn and 162.400 in Columbus - physically located in Phenix City).
NOAA Weather Radio is useful anytime, but is most important during severe weather. During threating weather, normal broadcasts are interrupted by important severe weather information. WATCHES, WARNINGS and current statements are given the highest priority and are updated frequently.
In an Emergency, each NOAA Weather Radio station will transmit a warning alarm tone signal followed by information on the emergency situation. This signal is capable of activating specially designed receivers by increasing the volume or producing a visual or audible alarm. Not all weather band receivers have this capability. But all radios that can receive NOAA Weather Radio can receive emergency broadcasts. The warning alarm device is tested each wednesday, usually between 11AM and noon central time, weather permitting.
A feature is available in the newest Weather Radio receivers called SAME which stands for Specific Area Message Encoding. SAME technology allows radios to be programmed to receive WATCH and WARNING message for your choice of Counties in your area without disturbing users for WATCHES and WARNINGS outside of the desired area. Local medial outlets are urged to use NOAA Weather Radio for up to date weather information and may free rebroadcast NOAA Weather Radio transmissions.
A new source of Weather information is the National Emergency Alert System (EAS), which replaced the Emergency Broadcast System. The EAS is a system of communications links that utilize data in a digital form. It is a reliable means of linking the NWS, Emergency Management Agencies, TV and Radio broadcast media together. The EAS will help participating radio and television stations receive and relay weather warnings and other emergency information in a timely manner. In the future, the EAS will expand to include Cable TV.
------------------------------------------------------------------------------
Your safety depends on being constantly aware of the possibility of severe weather. The best thing to do is start preparing the minute you hear the WATCH , take immediate action when you hear the WARNING and stay tuned to your NOAA weather radio or local broadcast media for the latest weather information.
NOW is the perfect time to review your emergency preparedness plans. Check food, water and other shelter supplies. Make sure your NOAA Weather Radio is working and has fresh batteries in it. Make sure you and your family know what to do if threatening weather approaches.
|
