Heavy to Excessive Rainfall in Montana; Bering Sea Low to Bring Impacts to Southwest Alaska

Heavy to excessive rainfall is forecast across portions of Montana Wednesday, along with an isolated flash flooding threat. A Slight Risk of Excessive Rainfall (level 2 of 4) is in effect for central Montana. A Bering Sea low will continue to bring strong winds, moderate to heavy rainfall, and high seas to southwest Alaska. A North Pacific Low may impact southwest Alaska at the end of the week. Read More >

Flash Flood

Flooding that begins within 6 hours, and often within 3 hours, of the heavy rainfall (or other possible cause)

Flash floods are the most dangerous kind of floods, because they combine the destructive power of a flood with incredible speed. Flash floods occur when heavy rainfall exceeds the ability of the ground to absorb it, or when enough water accumulates for streams to overtop their banks, causing rapid rises of water in a short amount of time. They can happen within minutes of the causative rainfall, limiting the time available to warn and protect the public.

Flash Flood Terminology

Flash Flood Watch	Flash flooding is possible within the designated watch area -- Be alert !
Flash Flood Warning	Flash flooding has been reported or is imminent -- Take necessary precautions at once!
Small Stream Advisory	Flooding of small streams, roads and low-lying areas is occurring.
Flash Flood Statement	Follow-up information regarding flash flood event.