dry slope 
(also dry-ski slope)
noun
An artificial ski slope used for practice and training: [as modifier]: dry-slope skiing...
- Get in some dry-slope practice at Glasgow Ski and Snowboard Centre, Bellahouston Park, Dunbreck Road, Glasgow.
- Over the next few weeks, they will try their hand at everything from dance, drama, and disc-jockeying to motorcycling, dry-slope skiing, costume making and web-site design.
- The only time I've been dry-slope skiing, it snowed.