The severe torque probably caused it to jump the splines.
You will probably have to pull the arm off and re align it on the side that is wonked.
It really is best to lift the wipers off the windshield before starting in freezing conditions to ensure they are free. I always clear the windshield from snow and ice and give a little pull upwards. If it is just frost, I will often just cheat & let the windshield warm up completely before activating the wipers.
Also when it is subzero I let the car totally warm up for 20 minutes before using the power windows. To aid in motor action, I recently sprayed silicone on all the rubber seals to make it easier for the windows not to stick and to condition the rubber seals for winter conditions.
1997 Buick Pk Ave (Soft Ride) Suspension!