The phrase "polar plunge" refers to a daring activity where people jump or dive into very cold water, typically during winter or in icy locations. Full definition
So with ice floating by, we put on our game faces and challenged ourselves with the coldest of polar plunges. (uncruise.com)
Saturday's polar plunge appears to have been a success; as of Monday, over $ 33,000 was raised. (shelterme.tv)
It includes an aromatherapy steam room, showers of various temperatures and intensities, clay steam room, sauna, ice room, Jacuzzi, polar plunge pool, footbath and «sensations pool» filled with waterjets of various shapes and pressures. (tripsavvy.com)