Winter Storms
Winter Weather Terms
Being familiar with terminology used by the Weather Service will help you know what to expect when weather warnings are issued. The following terms are used frequently in reference to winter weather.
- Freezing rain - occurs when temperatures
are below 32 degrees F and rain freezes on impact. This causes
an ice coating on all exposed surfaces. If the coating is heavy,
falling trees or wires can be additional hazards.
- Ice storm - freezing rain or drizzle is
called an ice storm when a substantial glaze layer accumulates.
In some parts of the country, ice storms are called "silver
thaws" or "silver frosts."
- Silver thaw -
term used in reference to an ice storm.
- Silver frost -
term used in reference to an ice storm.
- Sleet -
frozen rain drops (ice pellets) that bounce on surface
impact. Sleet does not stick to other objects, but sufficient
accumulations can cause dangerous driving conditions.
- Traveler's advisory -
report to inform travelers that falling snow and/or drifting
snow, strong winds, freezing rain, drizzle of other weather
condition may make driving hazardous.
- Blizzard -
when wind speeds of 35 miles per hour or more, with blowing
or drifting snow, are expected.
- Severe blizzard - great density of falling
and/or blowing snow, wind speeds of 45 mph or more and temperatures
of 100 degrees F or lower.
- Snow squalls -
brief, intense snow falls accompanied by gusty surface
winds.
- Stockmen's
advisory -
report issued when weather combinations (cold rain and/or
snow with temperatures of 45 degrees F or colder and winds
25 miles per hour or higher) occur. If the temperatures
are in the mid 30's or lower, the wind speed criteria for
an advisory is lowered to 15 miles per hour.
- Wind
chill factor - the combined effect
of wind and cold. (For example, a very strong wind combined
with a temperature below freezing can have the same chilling
effect as a temperature nearly 50 degrees lower with no wind.)
- Snow
drift - snow banked up by the wind.
- Heavy snow - when four or more inches of snow fall during a 12-hour period, or when six inches or more fall during a 24-hour period.