FLASH FLOOD AND HEADWATER GUIDANCEFlash Flood Guidance is used to predict flooding of smaller streams. Values are calculated for 1, 3, 6, 12, and 24 hour time periods for each county. Each value means: "if that amount of rainfall occurs over the given county in the given time period flooding of small streams is likely". It should be noted that these values are meant as guidance only. Just because 2 inches of rain falls in an hour in a county where the 1 hour flash flood guidance is 1.5 inches does not mean there will be flash flooding. Also it should be noted that this guidance is not applicable for urban, basement, or other flooding not associated with a stream.
Headwater Flood Guidance estimates
how much rain is needed to bring selected headwater streams to
flood in a given amount of time. As with flash flood guidance,
these numbers are meant to be used as guidance only.
County Flash Flood Guidance - text products
SIGNIFICANT RIVER FLOOD OUTLOOK