The suit said that the Forest Service's environmental and financial analysis of the expansion is outdated, the Ashland Daily Tidings reported.
The plan, approved by the agency in 2004, has been the subject of a lawsuit and multiple appeals.
In August, a judge lifted an injunction that had blocked the expansion. The lawsuit, filed last week in federal court by the Sierra Club, Oregon Wild and the Center for Biological Diversity, seeks a new injunction.
The association that runs the nonprofit ski area hasn't begun on-the-ground expansion work.
The first phase, including new ski runs and lifts, is expected to cost about $3.5 million, according to 2011 estimates.
The lawsuit said the expansion analysis failed to consider cumulative impacts on the Ashland watershed from the expansion and from wildfire fuels thinning, potential climate change impacts on snowfall and skier visitation, and new state limits on the amount of sediment that can flow into Reeder Reservoir in the watershed.
Most of the ski area and the proposed expansion are in the watershed, the source of Ashland's water supply.
"A large amount of information has been developed since the expansion was first approved," said Marianne Dugan, a Eugene-based environmental attorney working for the plaintiffs.
The complaint said the groups do not oppose some parts of the expansion, such as a snow tubing facility, some widening of existing runs, new runs by a beginner's hill and watershed improvement projects.
Kim Clark, the general manager of the ski area, said the association and its lawyers are still reviewing the complaint.
"At this time, we're not aware of any basis for us making any change in the expansion," Clark said.
The ski area opened on Dec. 6 after early snow hit the mountain.
More Northwest Headlines
With protest over, Shell prepares for Arctic Ocean drilling Lawsuit over lease for Shell Arctic drilling fleet rejected Higher wages a surprising success for Seattle restaurant Court denies Medina millionaire’s release from Montana jail Prosecutors charge man in fatal Bonney Lake crash Woman, 87, goes missing while picking berries in Skamania County New wildfire burns at least 8 structures in Mason County Judge tosses lawsuit seeking Kurt Cobain death-scene photos
Our new comment system is not supported in IE 7. Please upgrade your browser here.