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DNRC Headquarters
1539 Eleventh Ave. Helena, MT 59601
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Carbon County Flood Maps Update


Background on the floodplain maps in the County:

Carbon County floodplain maps were modernized through a Digitized Flood Insurance Rate Map (DFIRM) project in 2012. The maps were converted from paper to the digital environment. Most of the mapped floodplains in the county are still based off flood studies from the late 1970s and early 1980s.  The 2012 DFIRM project entailed digital conversion of the effective floodplains in the county, with the exception of revised hydraulics and mapping on 9 miles of the Clarks Fork of the Yellowstone (upstream from the Carbon/Yellowstone County border). This revision, however, did not include updated hydrology or survey data. In 2017 a Partial Mapping Revision (PMR) was completed for the portion of the Yellowstone River in the county.  The PMR leveraged US Army Corps of Engineers information from a Yellowstone River corridor study and updated floodplain mapping in Stillwater and Yellowstone Counties to update and replace the approximate floodplain mapping on the Carbon County side of the Yellowstone River with enhanced and floodway mapping.


2019 Project

DNRC with support from Carbon County applied and received a FEMA grant to update the flood study and floodplain maps for the Clarks Fork of the Yellowstone, Rock Creek, and tributaries.

DNRC held a project kick off meetings on October 3rd & 4th, 2019 with Carbon County, Joliet, Red Lodge, Bear Creek, and Fromberg. To view the slides that were presented click here. 

Below is the study extents for the project. To view a larger image click here. 

The project timeline below is just an estimate. Weather can delay data gathering, data review and revisions can require some back and forth, but if the project goes according to plan below is the tentative project timeline. Click here to view the project timeline.

Project Points of Contact

Annie Gillespie
Carbon County Floodplain Administrator 
(406) 445-7300

Tiffany Lyden
MT DNRC Outreach Specialist
(406)444-0599

Nadene Wadsworth
MT DNRC Outreach Specialist
(406)444-6732