It used to be easy. Google 'Fire Name' + ICS-205.
They're now deep secrets for some unknown reason.
Anyway...
The fire is burning on Yakima Nation, Washington State Department of Natural Resources
and US Forest Service lands on the south and west flanks of Mt Adams.
Search for and note each of those agency's freqs for that area.
Also...
A freq or two are posted in most, if not all FAA Notice to Airmen (NOTAM)
that are issued on big fires.
For the Cougar Creek Fire -
NOTAM Text
132.225 MHz AM is listed.
Keep an ear there, and you may hear other freqs mentioned.
Dont forget :
Natl Incident Radio Support Cache / NIFC
https://www.radioreference.com/apps/db/?aid=7769
Google "2014 ODF Aviation Procedures Manual.pdf"
Open it.
On page 55 of this doc is a map of A/A & A/G freqs.
Those freqs are NOT exclusive to ODF.
Be SURE to include them in your scanning.
There's a start.
We'll be anxious to see if you find anything new.
Have a great time and be safe!
I've put in the request to RETURN the function to the state of the Fire
as well as the Mountain you are asking about.
I've put in a request that it be LOCKED permanently into the Oregon forum.
The man likely wouldn't have got an answer elsewhere.
Go eat a pot of beans.