Art Bernstein is probably right -- your wipers (held by the ice while the motor turned their shaft) slipped and are in the wrong position.

But I just wanted to add that not all models' (viz. model years) wiper arms are held by that bolt that Art mentioned. You may have the kind that are just held on by a tight fit. If you don't have a plastic cap covering a bolt head on top of the base of the wiper, then you just have to pry the wiper arm off the shift. Use a big screwdriver to lever it up, but be sure to use a soft piece of wood as a pivot or fulcrum, so you don't mar your paint or crack your glass.

The wiper arms are supposed to retain their position by numerous grooves that engage counterpart grooves in the shaft, and the wiper arms are made of softer metal (fortunately -- good foresight, Volvo!) than the shaft. Sometimes they wear down and the arms slip (first hand experience), they'll get out of position more and more often (your "ice experience" may have exacerbated this for you) and at that point you probably want to buy new arms -- and now it's clear why that foresight was good; it's a lot easier and cheaper to replace those arms than the shafts that drive the wipers.

Good luck.