Tornadoes

Severe Weather Preparedness Week 2013
Day 3 - Wednesday February 6, 2013

This is day three of Severe Weather Preparedness Week. Today’s topic
is tornadoes.

A tornado is one of nature's most violent storms. It is a violently
rotating column of air in contact with the ground. Tornadoes vary
greatly in size, intensity and appearance. Tornado winds can
range from less than 100 mph to in excess of 200 mph with the stronger
tornadoes. The time tornadoes stay on the ground can also vary
from a quick touch down that does little or no damage to one that
stays on the ground for several hours and destroys nearly everything in
its path.

During 2011, there were a total of 97 tornadoes confirmed across
Mississippi. There were 68 tornadoes that were rated as EF0 or
EF1, which are considered to be weaker tornadoes. There were 15
tornadoes that were rated EF2 and 11 that were rated EF3. EF2 and EF3
tornadoes are considered to be strong. There was 1 EF4 tornado and 2 EF5
tornadoes in 2011. EF4 and EF5 tornadoes are considered to be violent.

The violent tornadoes all occurred on the afternoon of April 27. The
highest impact tornado, an EF5, hit the town of Smithville in Monroe
county causing extensive damage. A second EF5, moved through parts
of Neshoba, Kempner, Winston, and Noxubee counties. An EF4 tornado
tracked from Smith County across Jasper and Clarke counties and then
continued into Alabama.

When one looks at long term statistics for the number of tornadoes, strong to
violent tornadoes, long track strong to violent tornadoes and unfortunately
tornado fatalities, Mississippi ranks at or near the top in every category.
This presents a preparedness problem to the residents of the state.

Spotting tornadoes in Mississippi can be very difficult. Many of the tornadoes
are wrapped in rainfall, are hidden by trees, and have a forward motion up to
60 mph. Also, many tornadoes in the state occur at night which makes it very
difficult to warn the public.

Tornadoes can and do occur in every month of the year. In a normal year
there is a high frequency of tornadoes in the spring months from February
through May.

A tornado watch is issued when conditions are favorable for the
formation of both tornadoes and severe thunderstorms over a
particular area. During a watch, remain alert for signs of
threatening weather and make preliminary plans for action. People
who live in mobile homes should have plans for seeking shelter in
a more sturdy structure.

A tornado warning is issued when a tornado has been sighted by
a spotter or detected on radar. When a warning is issued it is
time to take necessary action to save your life.

A tornado emergency is issued when environmental conditions
favor the development of a strong or violent tornado, radar
indicates very strong rotation in a storm, and storm spotters
report a large tornado. The tornado emergency will only be issued
in rare situation where these criteria are met.

The National Weather Service will conduct a tornado drill this
Wednesday morning using the routine weekly test on NOAA Weather
Radio. We encourage schools, business, hospitals and families to
participate in this drill. It is important to know what to do when
severe weather approaches. Do not wait until the tornado impact is
imminent to decide what actions you are going to take.

Tornado safety rules are listed below.

In homes or small buildings, go to the basement or to an
interior room, interior hall, or to small rooms such as a
closet or bathroom on the lowest level. Get under something
sturdy like a heavy table or bed.

In schools, nursing homes, hospitals and shopping centers,
go to a pre-designated shelter area. Interior hallways on
the lowest floor are usually best. Stay away from large windows
or glassed areas. Also, stay away from large rooms like dining halls
or gymnasiums because they may have weakly supported roofs.

If you are in mobile homes or vehicle, leave it and go to a
substantial structure. If there is no shelter nearby, lie flat
in the nearest ditch, ravine, gully, or culvert with your
hands shielding your head. However, this may not be a good option
if heavy rain is falling.

Stay away from windows. Do not bother opening them. Opening windows
will not protect the structure but will in fact lead to more damage
if hit by a tornado. Also, you will just waste time and put yourself
and possibly others at greater risk. Use those valuable few seconds
to find safety.

Stay away from doors, windows, and outside walls.

Remember, tornadoes form very quickly and may occur with little
or no advanced warning. You may have only a few seconds to
find shelter. When a tornado threatens, your immediate action
can save your life.

Take the time this week to teach your children or your co-workers
about tornadoes. Show them the best shelter areas in your home
or business.

National Weather Service Weather Forecast Office