OMG!!!!!!! ever been so screwed before ?

i'm so (offensive language removed). hey all. so i'm an aspiring beginner film maker and about to film a scene that involves being on top of a very high mountain peak covered in snow. however, i do not have accessibility to a solicitation removed so i was thinking if it would just be more simple to film on location? or is it possible to simply build my own green screen from supplies i can acquire at home or buy from a hardware store? I have absolutely no knowledge with these kind of shots and the movie needs to be completed in the next couple of days! anyone have any suggestions? please help!!! What would you do in my situation? also, how much is it to rent a studio with a green screen?