Public Information Statement
Issued by NWS Goodland, KS
NOUS43 KGLD 281220
...2017 Severe Weather Awareness Week for Nebraska...
Today marks the second day of Severe Weather Awareness Week for the
state of Nebraska, which continues through Friday, March 31st.
The topic for today is Severe Thunderstorms.
A thunderstorm is considered severe when it produces hail that is
one inch in diameter or larger, damaging winds equal to or greater
than 58 miles per hour, or a tornado.
There are numerous aspects of severe thunderstorms that pose a
threat to life and property. Along with the threat of large hail,
damaging winds, and tornadoes, everyone must also be aware of the
possibility of dangerous lightning and flooding. Lightning,
flooding, and tornadoes will be discussed later during the week.
Hail is produced in a thunderstorm as rising currents of air, known
as updrafts, carry water droplets to a height where freezing occurs.
Hail continues to grow inside of a thunderstorm until it becomes too
heavy and can no longer be supported by the storm updraft. Once
this occurs, the hailstone falls to the ground. Large hail is an
indication that a thunderstorm is quite intense with a very strong
updraft. The largest hailstone ever recorded in the United States
fell in Vivian, South Dakota. This hailstone had a diameter of 7.9
inches, a circumference of over 18 inches and weighed 1.94 pounds.
Another significant severe weather threat is damaging winds,
which can be caused by an event known as a downburst. A downburst
is a small area of rapidly descending air beneath a thunderstorm.
Once this descending air hits the ground, it spreads out in all
directions. Downbursts and the resulting straight line winds can
cause damage comparable to a tornado.
Additional information on severe thunderstorms, hail, and wind can
be found at: