MID-SOUTH SEVERE WEATHER AWARENESS WEEK February 28 March 5, 2016 In preparation for the spring severe storm season, the week of February 28-March 5 has been declared Mid-South Severe Weather Awareness Week. Monday through Friday of the week, your NWS Office in Memphis will post graphics, information, and statements discussing the weather hazards we face. The dates and topics are listed below: Monday Feb. 29 Severe Thunderstorms Tuesday Mar. 1 Floods Wednesday Mar. 2 Tornadoes Thursday Mar. 3 Lightning Friday Mar. 4 Warning Reception Severe Weather Awareness Week is an excellent time to ensure that you and your family are ready for severe weather season. It s an opportunity to practice your severe weather plan at home, school, and work. It s a chance to ensure you can receive critical severe weather information in time to take action to protect yourself. TORNADO DRILL AND SAFETY SELFIES 9:15 AM, Wednesday March 2 The mock warning will be broadcast as a weekly test message on NOAA Weather Radio. The drill is a great time for everyone to ensure their NOAA Weather Radios are in good working order and to test their severe weather plans. During the tornado drill, take a safety selfie in your shelter location. Tweet it using the hashtag #safetyselfie. Let everyone know that you re ready for severe weather! We at NWS Memphis will retweet the best of the Safety Selfies that we see. TWITTER Q & A PROGRAM During the week, NWS Memphis will conduct a severe weather preparedness question-and-answer session on Twitter. NWS meteorologists will be available to answer questions regarding Mid-South weather hazards, the severe weather warning system, and severe weather planning. Details on the Q&A program will be coming soon.
SEVERE THUNDERSTORMS A thunderstorm is considered severe if it produces one or more of the following: * Hail 1 inch in diameter (the size of a quarter) or larger * Wind 58 mph (50 knots) or stronger * A tornado Thunderstorm Winds Straight-line winds are any winds not associated with the rotation of a tornado. Straight-line winds are responsible for most thunderstorm wind damage. Straight-line winds can exceed 125 mph! A downburst is a small area of rapidly descending air beneath a thunderstorm. Thunderstorm winds can cause damage equivalent to a strong tornado and can be extremely hazardous to aviation. Hail Hail is the most destructive hazard produced by thunderstorms, causing over $1 Billion in damage each year. Large hailstones can fall at speeds faster than 100 mph! The largest hailstone ever recovered in the United States was a 7 inch wide chunk of ice that landed in Aurora, Nebraska, in June 2003. Severe Thunderstorm Safety Tips If a severe thunderstorm warning is issued for your area, or if storms approach, move inside a strong building and stay away from the windows. Don t minimize the threat! Non-tornadic severe storms have caused six deaths, 30 injuries, and over $500 Million damage in Tennessee, Arkansas, and Mississippi since 2013. Mobile homes and vehicles offer poor protection from thunderstorm winds, especially winds that are stronger than 70 mph. Move to a stronger shelter if possible. Vehicles offer protection from hail smaller than the size of a golf ball. Hail that is golf ball size or larger may break the windows.
FLOODS Flash floods are the #1 thunderstorm-related killer. A flash flood is a rapid rise of water, usually during or shortly after a heavy rain event. Flash floods can also occur due to dam breaks, levee failures, or debris jams underneath bridges. Most flash flood deaths occur in vehicles. Two feet of moving water is sufficient to float most vehicles. Flash floods can wash out road beds and damage bridge pilings. Six inches of moving water can knock you off balance, and you may slip and fall into the water. A river flood is the inundation of a normally dry area caused by an increased water level in an established river. River flooding is usually caused by widespread excessive rain, persistent thunderstorms over the same area for an extended time, and spring snowmelt. River floods can last for days or weeks depending on the situation. The 2011 floods caused over $2 Billion damage. River flood severity is classified as minor, moderate, and major based on the impacts which may result. Flood Safety Tips Know your flood risk. If you are in a risk area, have an evacuation plan in place before flooding occurs. Discuss flood plans and flood safety with your family. Turn Around, Don t Drown! Stay clear of flooded areas or areas where water covers the road. If you are driving and encounter flooding, find a different way to your destination or wait for the water to go down. If you are camping or hiking, learn where the high ground is in your area and how to get to it quickly. Have a NOAA Weather Radio and other ways to keep up with weather developments. If a flood or flash flood warning is issued for your area, act quickly. Keep children from playing near rivers, creeks, and drainage ditches. Be extra careful at night, when the water depth can be harder to see, and the road condition can be difficult to determine.
TORNADOES A tornado is a violently rotating column of air, attached to the base of a thunderstorm, and in contact with the ground. Each year, over 1,200 tornadoes strike the U.S., causing over 60 fatalities and 1,500 injuries. The average tornado lasts 8-10 minutes and covers a couple of miles along the ground. The longest-lived tornadoes can last for over an hour, and may have path lengths of over 50 miles. Tornadoes are rated using the Enhanced Fujita (EF) Scale, which goes from EF-0 to EF-5. EF-0 and EF-1 tornadoes are considered weak, EF-2 and EF-3 are strong, EF-4 and EF-5 are classified as violent. Weak tornadoes may still have winds stronger than hurricane force. Violent tornadoes may have winds in excess of 200 mph. The Holly Springs-Ashland, MS tornado of December 23 was one of only three EF-4 tornadoes to occur in the U.S. in 2015. It was up to 3/4 mile wide and had a path length of over 70 miles. Tornado Safety Tips Practice your tornado safety plan, so everyone knows what to do during an actual event. At home, school, or work, an underground shelter is the best place to be. An above-ground safe room is the second-best place to be. If no shelter or safe room is available, go to a small interior room (without windows) on the lowest floor, such as interior bathrooms or hallways. Use blankets or overcoats for protection, and put on a helmet if one is available. If you are driving, get to a sturdy reinforced building and follow the above tips. Avoid overpasses they are NOT safe shelters in a tornado. If you are in a mobile home, get to a sturdy reinforced building and follow the above tips. If you are in the open and no building is nearby, get into a ditch or depression and cover your head. Beware of flash flooding, though!
LIGHTNING Lightning is an electrical discharge from a thunderstorm. Lightning is the #2 thunderstorm-related killer in the U.S., trailing only flash floods. The temperature of a lightning strike can reach 50,000 degrees F, and the energy from a single lightning strike could light a 100-watt light bulb for 3 months. Lightning tends to strike the tallest objects in an area, such as trees, light poles, telephone poles, and radio towers. Lightning can strike many miles from the rain area of a thunderstorm. If you can hear the sound of the thunder from a storm, you are in range of the lightning. The majority of lightning victims were going to a safe place when they were struck, but waited too long before seeking shelter. Lightning Safety Tips If a thunderstorm approaches, go inside a strong, grounded building. If no building is nearby, take shelter in a hardtop vehicle. If time permits, turn off and unplug all non-essential electrical items. If you are boating, camping, or golfing, take a NOAA Weather Radio or other ways to find out about weather developments. Give yourself plenty of time to get to shelter if storms approach. Don t use a corded phone during a lightning storm. Cell phones and cordless phones are safe to use. Stay inside for 30 minutes after you hear the last thunder. Give the storm time to move a safe distance away.
WATCHES AND WARNINGS Make sure you know the difference between a watch and a warning. A WATCH means that conditions are becoming favorable for tornadoes and/or severe thunderstorms, or flash floods. A WARNING means that the hazardous weather (tornado, severe thunderstorm, flash flood) has been observed and reported, or detected on radar. WATCHES are valid for several hours, and typically cover a large area (most of west Tennessee, northern Mississippi, or eastern Arkansas, for example). WARNINGS are usually valid for less than 1 hour, and are issued only for the areas that will be affected by the particular storm or flash flood. During a WATCH, pay closer attention to the weather. Make sure that your severe weather plan is ready. Be ready for action if a warning is issued or storms approach. During a WARNING, listen closely to the text of the warning. If you are near the forecast path of the storm, then take action immediately! How To Receive Warnings NOAA Weather Radio is one of the best ways to receive watch and warning information. NOAA Weather Radio is a 24-hour continuous broadcast of weather information directly from NWS offices. Weather radio receivers have alarms that activate when a watch or warning is issued for your county. Weather radios may be purchased at some department and home improvement stores, and online. Make sure that your weather radio has a battery backup, and the SAME (county-specific) capability. NWS Offices are now posting weather information on Twitter and Facebook. Facebook is used mainly for outlooks, summaries, and general weather information. Twitter is used mainly for fast-breaking information such as warnings and storm updates. Our addresses are: http://www.facebook.com/nwsmemphis, and http://www.twitter.com/nwsmemphis, and our Twitter handle is @NWSMemphis. All of our watch and warning information is posted on our website, http://www.weather.gov/memphis. The website also features radar and satellite images, climate data, safety and preparedness information. A number of companies have developed innovative apps for smartphones. Many of these apps use the phone s location service to determine if you are in a warning area or not, and will alarm only if you are in (or very close to) the warning area. Some of the apps also include access to radar data and the actual text of the warnings. We cannot endorse a particular app or manufacturer; however, we encourage you to ensure that your app uses official NWS information.