Wont be the first time.
Just post the % of income over expense per season with your per capita share of running the hill extrapolated over 365 days figured in. Yes, cutting grass in the summer is part of your cost basis. If the hill wasnt open, you coudnt teach there. FYI, so are the years that you dont get snow and cant teach. Even if the income from your dept bought part of two groomers last year, are you a liability or a income this year, over 5 years, 10? It isnt a month to month budget. You realize that those groomers are part the cost of your employment also right? No groomers, no groomed slopes, no newbies, no training, no instructors. No man is a island.
I know my loaded labor rate, ie what it costs to pay me, my insurance, taxes, my truck, tools, cost of company buildings, support staff, infrastructure, advertizing. Its about 5X my pay. Whats yours? Do you think that your cost of employment is what you get in a paycheck?
That is where your argument has to be if you want a raise anyway so it might be good to know. If it ends up as a loss leader, then you have to prove that because of your being there, the MT makes more money from returning customers. You have to justify that as a union rep in negotiations or as a private individual. If you dont have snow this year, then your value is a negative one to the MT.
I said before, no dog in the fight. I have been union and non and grew up in a family run company. Either way, you MUST PROVE your value if you want a raise and the money has to be there, meaning you cant make the case using only the good months mid season when everyone is on vacation. If you can make that case that your value is substanital enough to the company, then you should be getting a raise.