Snowmobiling on Forest Service Roads in Washington

That's a nice map, and specific to a small area. However, those type of maps typically include only those roads that are groomed, managed as winter rec. areas, and originating from snowparks. What about the roads that are not groomed, not designated winter recreation sites, not closed for wildlife, not in a non-motorized area, not specifically closed/gated, etc. Those lonely roads that are deeply covered with snow, leading to skiable terrain. Are they fair game to travel on via snowmobile?

This pretty much answers my question...

Snowmobiles on Forest Service Roads from the MB-SNF

"Most Forest Service roads are open to snowmobiles once the road is snowed out and impassable for wheeled vehicles. There are some exceptions and they include the following:
Snowmobiles are prohibited beyond gates during designated road closure dates.
Snowmobiles are not allowed on any Forest Service road that is opened to wheeled vehicles.
Snowmobiles are allowed on Forest Service roads beyond Snow-Parks once signs are posted stating: "No Wheeled Vehicles Allowed Beyond This Point."
The law prohibits snowmobile use in wilderness areas. The following is a list of Wilderness Areas that are in or partially in the Mount Baker-Snoqualmie National Forest:
Clearwater Wilderness
Norse Peak Wilderness
Alpine Lakes Wilderness
Henry M. Jackson Wilderness
Boulder River Wilderness
Glacier Peak Wilderness
Noisy-Diobsud Wilderness
Mt. Baker Wildernes
The Mt. Baker National Recreation Area is CLOSED to snowmobiles (03-JULY-2008).
The NRA including Schriebers Meadow is open to snowmobiles when snow depth exceeds 24 inches at the trailhead. It is the snowmobile drivers responsibility to observe this regulation."

Hey Toby T,
I would recommend calling the forest department for closures, as well.
I received a nice $275 ticket on a snow covered non posted road last spring. Turns out it was one of only two roads in the Robe valley that are permanently closed to snowmobiles. Hopefully with my generous donation they will be able to afford to post a little sign

Wait I didnt know you could ride a snowmobile into the Mt Saint Helens Devestation Zone is this true ?

Thanks for the input about the ticket Shred. It wasn't Mt. Pilchuck road was it? If so, that has some easy to find info. about it being closed to motors. Although I think that change was a fairly recent one.
Kyle, I'm not familiar with that side of St. Helens. Maybe acarey can help out on that one. I have wanted to access that NE side of the rim for something different, but have never got around to it. Upon quick search, I found that the FSR 99 into windy ridge is washed out at some point. I think about 7 (?) miles from windy ridge.

That road into Goat Rocks Wilderness looks a little strange to me. Can you really snowmobile to Walupt Lake, which is within the Wilderness Boundary? See where the confusion sets in!!??