 |
OCEMA Ogle County Emergency Management Agency email:
eoc@oglecounty.org |
Spotters Information Weather FAQ's Winter Weather Definitions Fujita Scale
ESDA HOME Back to County Index
Definitions
Watch
Conditions are favorable for severe weather in or near the watch area. Watches are issued for tornadoes, severe thunderstorms and flash floods, and are for relatively large geographic areas, such as portions of or multiple states.
Warning
The severe weather event is imminent or occurring in the warned area. Warnings are issued for tornadoes, severe thunderstorms, flash floods and river flooding and are for relatively small geographic areas, such as single or small groups of adjacent counties.
Severe Thunderstorm
A storm that produces hail 3/4 inch in diameter or larger and/or wind gusts of 58 mph or more.
Flash Flood
A rapid rise in water, usually within 12 hours of a period of heavy rain or other causative agent (i.e. dam break).
Downburst
A strong downdraft with an outrush of damaging wind on or near the ground.
Funnel Cloud
A rotating cone-shaped column of air extending downward from the base of a thunderstorm (or a wall cloud), but not in contact with the ground.
Tornado
A violently rotating column of air extending from the base of a thunderstorm (or a wall cloud), in direct contact with the ground.
Rain Free Base
An area of smooth, flat cloud base beneath the main storm tower, where little or no precipitation is falling.
Wall Cloud
An isolated lowering of the rain-free base found near the updraft/downdraft interface, indicating the strongest inflow or intake into the thunderstorm.