Tornadoes’ high wind speeds, ability to travel long distances, and quick striking ability with minimal warning can make them are one of nature’s most fearsome phenomena. These destructive rotating columns of air come in contact with the ground and make their ways along a span of land, picking up dust and debris and obliterating structures in their way.
According to the National Oceanic and Atmospheric Administration (NOAA), the highest tornado wind speed on record was 318 mph, measured on May 3, 1999, near Bridge Creek/Moore, Oklahoma. The greatest death toll came from the “Tri-state tornado,” which killed 695 people along its 219-mile track through Missouri, Illinois and Indiana on March 18, 1925. About 1,000 tornadoes touch down each year in the United States, leading to about 60 deaths annually. A very small percentage of these storms reach the top forces on the Fujita scale, the measurement used to indicate the strength of a tornado based on wind speed.
Though tornadoes can be very destructive, certain climatic factors indicate when one could possibly form. and allow for preparedness measures. Be aware of the following signs, which indicate that conditions are right for tornado formation:
- Dark, often greenish sky
- Wall cloud (a large, lowering and rotating base of a cloud)
- Large hail
- Loud roar, similar to a freight train
According to the NOAA, thunderstorms develop in warm, moist air in advance of eastward-moving cold fronts. These thunderstorms can produce large hail, strong winds and tornadoes. In the winter and early spring, tornadoes are associated with storm systems moving from central U.S. states to the east. In these cases, several states may be affected by numerous severe thunderstorms and tornadoes.
During the spring in the Central Plains, thunderstorms frequently develop along a “dryline,” which separates very warm, moist air to the east from hot, dry air to the west. Tornado-producing thunderstorms may form as the line moves east.
According to NOAA, along the front range of the Rocky Mountains, in the Texas panhandle and in the southern High Plains, thunderstorms frequently form as air near the ground flows “upslope” toward higher terrain. If other favorable conditions exist, these thunderstorms can produce tornadoes.
Important preparedness steps include developing a family plan about where to meet and what to do if a tornado is expected. Communication is the most important part of preparing. An additional communication source is keeping a battery-powered weather service radio in order to receive warnings. Some warnings and watches include:
- TORNADO WATCH: Tornadoes are possible in your area. Remain alert for approaching storms.
- TORNADO WARNING: A tornado has been sighted or indicated by weather radar. If a tornado warning is issued for your area and the sky becomes threatening, move to your pre-designated place of safety.
- SEVERE THUNDERSTORM WATCH: Severe thunderstorms are possible in your area.
- SEVERE THUNDERSTORM WARNING: Severe thunderstorms are occurring.
Make sure if the above warnings are issued to take proper safety actions: Find a safe place such as a pre-designated shelter or a basement. If an underground shelter is not available, move to an interior room or hallway on the lowest floor and get under a sturdy piece of furniture and stay away from windows.
Never attempt to escape a tornado by trying to outrun it in a vehicle; instead, leave it immediately. Stay in a pre-designated shelter or basement. As quickly as a tornado may approach, it may also leave the area rapidly.
To learn more about tornadoes from the National Weather Service, visit http://www.spc.noaa.gov/faq/tornado/.
Photo courtesy of the National Oceanic and Atmospheric Administration.