I saw in the recently published Shulchan HaLevi (p. 135) that R. Yisroel Belsky permits, based on the Rema, attending a holiday party. However, he adds that you should only do so if you must, you should not stay longer than necessary, and you should leave if the activities become improper.
In the most recent volume of the YU Torah journal Beis Yitzchak (link, pp. 236-238), R. Asher Bush discusses shoveling snow on Shabbos. In particular, he raises important points that I have not seen elsewhere regarding violating a rabbinic prohibition to prevent danger and exerting significant effort for the sake of a mitzvah.