Official Notice


This notice is intended for all addresses located in or adjacent to the 100-Year Floodplain between the Madison and Jefferson Rivers. Purpose of this Notification is to inform you of the Flood Hazard associated with these drainage ways and suggest possible actions one may take to protect yourself.


Maps showing the location of the 100-Year Floodplain are on file at the Three Forks City Hall. Floodplain information is also available in the Three Forks Community Library. Based upon these maps, approximately 90% of the residences lie within the floodplain and are flood prone.

The 100-Year Floodplain is an area that will be flooded on an average of once every 100 years. There is a 1% chance of being flooded in any given year. Putting it another way, it has a 25% chance of being flooded over the life of a 30-year mortgage. Smaller floods have a greater chance of occurring in any year and can still create a significant Flood Hazard to people and property. Three Forks is subject to flooding in January and February; flooding can be caused by extreme cold and ice jams.


City of Three Forks adopted a flood warning system. Warning will be disseminated by Local Sheriff's Deputies and Fire vehicles equipped with public address systems. Warnings will also be given Reverse 911 calls and by local radio station KGLT 91.9 FM.


In the Floodplain one should be concerned about Flood Hazard. There are several actions you can take to mitigate the flood hazard should it occur:

  1. Know the Flood warning procedure.

  2. Keep children away from flood waters, street drains or areas of deep water.

  3. Be especially cautious during hours of darkness.

  4. Plan escape routes; keep drainage ways open.

  5. Stay tuned to radio for flood warnings.

  6. Do not attempt to cross flooded water by foot or auto.

  7. Evacuate flood hazard area when advised by police or fire department.

  8. Be careful of electrical shock hazards that can occur by downed electrical wires.

  9. Obtain Flood Insurance.


Your Home Owner’s Insurance Policy will not cover losses due to flooding. For many people, their home and its contents represent their greatest investment. We strongly urge you, if you are in the floodplain, to protect yourself against losses due to flooding.

Information about flood insurance can be obtained from your Insurance Agent. You do not have to live in a floodplain to qualify for flood insurance. Renters can insure their possessions and property owners can insure their buildings and contents.

Just because your house has not been flooded in the past does not mean you are safe. There is also a 30-day waiting period from the date of application before a flood insurance policy takes effect.


Information concerning permanent and emergency measures that you can take to protect your property can be obtained at the City Office or additional information is available at the Three Forks Library. Steps necessary to retrofit a house (i.e. elevation, flood proofing, etc.) and measures to reduce damage during a flood (i.e. sandbagging, moving furniture, etc.) are explained. For more information contact the City Office.


Construction and development in a floodplain requires approval and review by the Floodplain Administrator. In most cases a floodplain permit must be applied for and issued prior to any development in the floodplain. The floodplain permit is required to ensure that construction and development is in compliance with the adopted regulations. Adopted regulations ensure only a minimal risk for property damage in the flood hazard areas. Illegal developments in the floodplain increase risk to all properties which are in the flood hazard areas. Any time an existing building is expanded by more than 50% of its market value or is more than 50% damaged in any way then the entire structure must be brought up to current floodplain regulations. Please report any suspected illegal construction to the City Office (285-3431).

The City also maintains a file of all Elevation Certificates and Letters of Map Amendments and Revisions that can be obtained upon request.


Maintenance of the existing drainage channels is necessary to ensure obstructions are not allowed to exist that would prohibit flood water free passage downstream. Illegal dumping into channels or free flowing areas can create areas which will allow debris to become stuck and thereby prevent free passage of flood waters down stream. Please report any illegal dumping to the City Office (285-3431).