FAQs

Property owners can contact the CDP and speak with the County Floodplain Manager, or you can go to the County's Interactive Mapping site and type in your address.

Yes. Public disclosure of a property in the floodplain before a sale is required by law. 

No. The County Floodplain Ordinance allows for some residential and non-residential building in the floodplain. Contact the CDP to find out about the requirements. 

Several benefits may result from implementation of flood mitigation improvements including:

1. Avoided property losses;

2. Avoided travel, business, and education interruption;

3. Avoided loss of critical infrastructure;

4. Revitalized neighborhoods;

5. Improved public spaces;

6. Enhanced public safety;

7. Enjoyed ecosystem benefits; and

8. Increased competitiveness for the community for other funding opportunities.

If flooding is imminent, residents can call Lewis and Clark County Disaster and Emergency Services and find out where the nearest sandbag filling site is. Property owners should elevate important documents and valuables in their home and keep extra drinking water on hand.

No. About 25% of flood losses occur outside of the regulated floodplain.

Yes. Flood insurance is available to anyone. Individuals that want to purchase flood insurance that aren’t near a mapped floodplain will also get a lower premium. 

An alluvial fan is a fan-shaped deposit of gravel, sand, and silt. An alluvial fan occurs where a fast-moving mountain stream empties out onto a relatively flat plain. When this happens, sediment that was being carried by the stream deposits itself in the stream channel as the water velocity slows. This causes a build-up of alluvial (stream-transported) sediments in the area where the stream slope abruptly changes from steeper mountain terrain to relatively flat valley terrain.

Alluvial fan flooding is common to communities in the mountains of the western United States. Alluvial fan flooding can occur when stream flows are large enough to exceed the channel capacity of the stream, causing the stream to flow out of its bank and into previously active alluvial fan channels. Many flood mitigation techniques applied to other flood-prone areas have limited or no effectiveness on alluvial fans. Many alluvial fan communities now recognize these unique hazards, or have experienced repetitive flooding problems, and are seeking to implement flood management and mitigation plans.

Yes. The County works to keep County Infrastructure free and clear of debris. Making sure trash, trees, branches, and other debris that accumulate around bridges will maintain flow capacity and reduce flood impacts, and is generally a good maintenance practice.

Residents can collect information about their property and submit a Letter of Map Amendment (LOMA) to FEMA for determination. In some instances, FEMA will approve a LOMA to remove the property from the floodplain.