Floods: Watch, Warning and Advisory Criteria

flood photo

The biggest part of being prepared is getting good information. Get familiar with National Weather Service terminology to understand weather forecasts.

In Maine, flooding can occur at any time of the year. However, typically, the greatest threat of flooding occurs in the spring when heavy rains and snowmelt can combine to produce excessive runoff. Ice jams can also produce flooding during the late winter and early spring.

To alert the public to these potentially threatening conditions, the National Weather Service isues flood WATCHES and WARNINGS.

FLOOD WATCH is issued when flooding is possible within the next 36 hours.
FLOOD WARNING indicates that flooding is imminent or is currently occuring.

The following are different types of Flood Warnings:

River Flood Warning

Issued specifically for major rivers, these warnings include forcasts of water levels and/or flows at certain points along the river. Widespread heavy rain, possibly coupled with snowmelt, is often responsible for this flooding.

Small River and Stream Flood Warnings

These warnings are issued by county for the smalle5r rivers and streams. Heavy rainfall, possibly combined with snowmelt, is often responsible for this type of flooding.

Flash Flood Warnings

These warnings are issued by county for rivers and streams when rapid rises in river and stream levels are expected during a short period of time. Heavy, slow moving thunderstorms and dam breaks are often the cause of this type of flooding.

Urban Flood Warnings

Issued for urban areas when local drainage systems are not able to handle the volume of runoff from heavy rain, and possibly snowmelt. In the fall, winter, and spring leaves or snow may contribute to the flooding by blocking drainage systems.

Coastal Flood Warnings

Issued when the combination of the astronomical tide and the storm surge will result in flooding of coastal areas. Onshore winds associated with large stroms contribute to this type of flooding.

Keep appraised of current weather conditions including latest FORECAST and any FLOOD STATEMENTS, WATCHES or WARNINGS for your area.

For More Information

National Weather Service

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