http://www.snozoneuk.com/html/snozone-portal/
http://www.skidxb.com/English/
http://www.thesnowcentre.com/
The above links are from Google using "indoor snow sports"
http://www.skiresorts.com/content/summer-skiing-usa
There is some limited backcountry in the Sierras (Lake Tahoe, Ca. U.S.A.) area at the moment. Farther north and or higher elevations should have more snow.
Backcountry has different risks than a resort, and serious attention to safety needs to be addressed.
South of the equator is going into the winter mode now.