A Flash Flood is a rapid and extreme flow of high water into a normally dry area, or a rapid water level rise in a stream or creek above an expected flood level, beginning within six hours of the causative event (e.g., intense rainfall, dam failure, ice jam). Please note, the actual time threshold may vary in different parts of the country.
Ongoing flooding can intensify to flash flooding in cases where intense rainfall results in a rapid surge of rising flood waters.
A Civil Emergency Message is issued by the National Weather Service in coordination with Federal, state or local government to warn the general public of a non-weather related time-critical emergency which threatens life or property, e.g. nuclear accident, toxic chemical spill, etc.
When this message is issued, it is advised to follow the instructions listed in the message and tune in to your local media outlet for further information.
Partly Sunny skies occur when 3/8ths to 5/8ths of the sky is covered by clouds. The term Partly Sunny is used only during daylight hours, and is replaced by Partly Clear at night.
Mostly Sunny skies occur when 1/8th to 2/8ths of the sky is covered by clouds. The term Mostly Sunny is only used during daylight hours, and is replaced with Mostly Clear at night.
An Alberta Clipper is a winter low pressure system that moves southeast out of the Canadian Province of Alberta and quickly passes over the Plains, Midwest, and Great Lakes regions of the US.
These systems usually bring snow, wind, and colder temperatures with it.
Humidity measures the amount of water vapor present in the air.