““Alpenvereinaktiv” and “Outdooractive”. You can switch between open-street maps and official data and determine whether (or how likely) there are any trails leading to the launch site. If a map shows just one trail, there is a 50:50 chance that it still exists. When in doubt: Give it a try!”
Assuming that no route is explicitly available for snowshoe or winter hikers, you should not climb up ski slopes because they are groomed during the evening and in the morning. You may face two hazards if you do decide to take such a hike: You could be run over by one of the snow groomers preparing the slope or you may fall over steel winch ropes that secure the groomers on the steep portions of the slope.