April through August are peak severe weather months for the continental United States. Climatological warming increases the risk of more severe thunderstorm events, which means people should get prepared now. Awesome technology is also improving advanced public warning, giving people the time they need to protect life and property. Despite advances in technology, life and death still involves personal preparedness responsibility. Surviving large hail, damaging winds, and killer tornadoes means knowing some basic science.
Severe Weather Science
According to Storm Prediction Center data for 2016, there were 20,238 severe weather reports. This breaks down to 1,059 tornadoes, 5,601 hail events, and 13,578 high wind events. The month of May had the most tornado reports, around 239, which is a statistically common month in tornado climatology. In 2016, the most severe weather reports happened between the months of April and August.
Tornadoes claimed 14 lives in 2016. However, there were 36 deaths in 2015, down from 47 in 2014. The deadliest place to be during a tornado is a mobile home or trailer. In 2015, 42% of deaths occurred from people being in mobile homes or trailers, followed by people in vehicles (28%).
Tornadoes can occur anytime, anywhere. Meteorologists rate tornadoes based on their damage (after they occur) using something called the Enhanced Fujita (EF) scale. Thankfully, the most violent tornadoes (EF-4/EF-5) are comparatively rare to weaker, more common (EF-0/EF-1). Strong tornadoes account for almost 70% of all tornado deaths.
The driving mechanism behind severe thunderstorms is not completely understood, especially when it comes to why some storms create tornadoes and others don’t. However, meteorologists have gained a very deep understanding of storm dynamics. There are several ingredients that come together to initially create and maintain dangerous storms. Some of these ingredients include: warm, moist air, wind shear, a lifting mechanism (front), and ample surface heating (usually 70°-80° F temperatures).
A front can become a strong gradient between different densities, especially during the spring as warm moist air meets with cold dry air. Fronts can enhance the risk of severe weather by forcing air to rise. Fronts and areas of wind shear are of particular interest to meteorologists. Wind shear is the change in speed in direction of wind with relatively short distance. The added changing wind direction, speed, and height factor can result in spins in the atmosphere. If the conditions are right, horizontal vorticity (spin) can be tilted in the vertical, which is a key theory in tornado development.
Surviving Severe Storms
It takes education and planning to survive severe weather. One major thing to help you survive tornadoes is knowing the difference between watches and warnings.
A severe thunderstorm watch is issues when severe weather is possible in and close to the watch area.
The definition of a severe thunderstorm is specific. In order to be called a severe thunderstorm, winds must be at least 58 mph or higher, and/or hail must be 1 inch in diameter or larger. It’s not rare for a severe thunderstorm to have large hail and high winds at the same time. It doesn’t take a tornado to kill. Keep in mind that severe thunderstorm winds can exceed 80 mph, which can cause significant damage.
A severe thunderstorm warning is issued when the criteria above is occurring or imminent. Severe weather can be detected by radar and also confirmed by storm spotters. Major severe weather outbreaks often include both ground severe weather reports as well as remote weather radar indications. Always take radar indicated warnings seriously, they are sufficiently accurate.
A tornado watch is issued when meteorologists are forecasting conditions favorable for severe thunderstorms and tornadoes. It’s not just large hail and high winds, it’s the added higher risk for tornadoes that sets this type of watch apart from the severe thunderstorm watch. Keep in mind that any severe thunderstorm can produce a tornado.
A tornado warning is issued when a tornado is indicated by radar or reported by a trained spotter. Many times there will be a radar indication of a tornado as well as a confirmed weather spotter report. Every tornado warning should be taken seriously and people should never hesitate to take cover immediately.
You may only have seconds or minutes to save your life, if a tornado threatens your location. Although we’re very good about issuing advanced tornado warnings (giving people several minutes to take cover), it’s possible that a tornado can occur with little to no warning. This is why it’s so important to pay close attention to rapidly changing weather conditions, especially during a severe weather watch.
The best place to be during severe weather is underground, away from windows, in a sturdy structure, surrounding yourself with as much strong material as possible (walls, etc.). If you are outdoors, find a sturdy structure indoors, or lie flat in a ditch while covering your head. If you are in a car, find a tornado shelter. There are some cases when you might be able to drive away from a tornado at right angles, if all other options fail. Never seek shelter under an overpass because winds are accelerated. Remember that watches and warnings are issued for a specific location and time. Pay close attention to the latest information from official sources to determine when it’s safe to come out of shelter. Part of knowing where you will seek shelter is to plan it all out while making your disaster preparedness kit.
Disaster Preparedness Kit
Once you understand the difference between watches and warnings, the key to surviving is having a disaster preparedness plan. These plans mean you know what to do in case of severe weather and also have the tools you need to prepare. Being prepared is much more than simply having some batteries and a flashlight.
The Federal Emergency Management Agency (FEMA) recommends people have a disaster preparedness kit that you can use to survive on your own for at least 72 hours. Visit the FEMA website for a list of things you might include in a disaster kit.
There are many ways you can stay informed on severe weather. The best source for official watches and warnings are your local National Weather Service office. All offices have a website with free weather information. You can also sign up for free text and email alerts from local news media. Never rely on outdoor warning sirens to alert you of a tornado. Always have more than one method of receiving weather alerts.
We also recommend getting a NOAA Weather Radio, which acts as similar to a smoke detector, only it goes off for severe thunderstorms and tornadoes. You can get a NOAA Weather Radio at most retail store locations or online. There are free programming videos all over YouTube that can help you set the radio up to alert your specific county.