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Winter Weather Definitions
| Blizzard |
The following life-threatening conditions are expected to prevail for three hours or longer:
(1) Sustained wind or frequent gusts to 35 mph or greater AND
(2) Considerable falling and/or blowing snow that frequently reduces visibility to less than 1/4 mile. |
| Blowing Snow |
Wind-driven snow that reduces surface visibility (6 miles or less). |
| Freezing Rain/Drizzle |
Rain/Drizzle that freezes on contact with surfaces such as the ground, trees, power lines, motor vehicles,
roads, etc. |
| Heavy Snow |
6 inches or more in 12 hours OR 8 inches or more in 24 hours. |
| High Wind | Sustained winds of 40 mph or greater, or gusts to 58 mph or greater (not due to thunderstorms), that
last for an extended period of time. |
| Sleet |
Pellets of ice composed of frozen or mostly frozen raindrops (or refrozen melted snow) that usually bounce
after hitting the ground or other hard surfaces. |
| Warning |
An NWS product that means severe weather or dangerous events are occurring or are imminent.
TAKE ACTION NOW! |
| Watch |
An NWS product that means conditions are favorable for severe weather or dangerous events to occur. Be alert,
monitor NOAA Weather Radio or any other weather information source, and BE PREPARED to take immediate action if the watch
is upgraded to a warning. |
| Advisory |
An NWS product that means conditions may become life-threatening if caution is not exercised. |
Spring and Summer Weather Definitions
| Flash Flood |
A dangerous rise in water level of a creek, stream or river in a few hours or less, caused by heavy
rain, ice jam break-up, earthquake, or dam failure. |
| Flood |
A rise in water level of a creek, stream or river that results in water overflowing into the surrounding
basin; usually caused by heavy rain, snowmelt, or a combination of the two. |
| Funnel Cloud |
A visibly rotating column of air extending from the base of a cloud but not touching the ground. |
| High Wind |
Sustained winds of 40 mph or greater, or gusts to 58 mph or greater (not due to thunderstorms), that
last for an extended period of time. |
| Microburst |
A small downburst from a thunderstorm with horizontal outflow winds extending 2.5 miles or less. Wind
speeds of 50 to 100 mph or greater are possible. Microbursts are usually associated with high based (dry) thunderstorms. |
| Severe Thunderstorm |
A thunderstorm which produces winds of 58 mph or greater and/or hail three-quarters (3/4)
of an inch in diameter or larger. |
| Tornado |
A violently rotating column of air that is in contact with the ground. Tornadoes usually develop from severe
thunderstorms and can produce winds of 100 to 300 mph. |
| Warning |
An NWS product that means severe weather or dangerous events are occurring or are imminent.
TAKE ACTION NOW! |
| Watch |
An NWS product that means conditions are favorable for severe weather or dangerous events to occur. Be alert,
monitor NOAA Weather Radio or any other weather information source, and BE PREPARED to take immediate action if the watch
is upgraded to a warning. |
| Advisory |
An NWS product that means conditions may become life-threatening if caution is not exercised. |
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National Oceanic and Atmospheric Administration
National Weather Service
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