Rating system used by the Unites States Forest Service. Like ski trail ratings, this system really only describes the relative difficulty of nearby trails.
Easy | 1-3 | These routes are appropriate for novice through advanced users. They generally follow obvious, well-marked trails and roads. Grades are gentle, and few obstacles will be encountered. |
More Difficult | 4-7 | These routes are appropriate for intermediate through advanced users. Terrain may be steeper, trails narrower, and some obstacles may be encountered. |
Most Difficult | 8-10 | These routes are recommended for advanced to expert users only. Terrain is steep, and routes are not well marked. You should have considerable skill in your chosen activity, as well as knowledge of navigation and survival before attempting these trails. |
Note: Trail ratings are highly subjective. A trail that is easy for an experienced driver with a highly modified vehicle may be impassable for a novice driver in a stock vehicle. Weather conditions may also significantly affect the difficulty of a trail. Also, the difficulty of a trail may change over time, as trail use, weather, and maintenance modify the trail. Always check with the managing organization and/or recent users before planning a trip on a trail and scout ahead on foot if you are not sure of current conditions.