This winter I have been doing some mapping of ski areas in Massachusetts and New Hampshire.

For many situations landuse=winter_sports works when mapping the larger ski area. However, some ski areas are run by third party organizations that are not the land owners, they basically just have permission to maintain the trails during the winter. Also, the land use during the summer/fall/spring is often better tagged as something other than winter_sports. Lastly, sometimes they are spread out.

osm.org/relation/4714756

osm.org/relation/4458787

In these situations, the site relation is a better fit. The parking lots, ticket counters, etc can be included. So far so good, there is even a site=piste tag/value, but it was voted on and rejected last year.

osm.wiki/Relations/Proposed/Tag:site%3Dpiste

I am using it anyway. Hopefully, the site=piste will be used enough that a re-vote can be happen again in the future.

http://www.opensnowmap.org/