We were in the North Atlantic once in the mid 70s aboard an LPH evaluating the Sea Control Concept. I had been sent on the evening iceberg patrol. Meantime the ship entered a heavy fogbank. Finally, with no fuel remaining, I had to make an instrument approach. When I tried to hover over the deck, I didn't have enough power to hover and landed rather hard. What was estimated, due to both the size of the piles and the anticipated hover power capabilities, at approximately 7,000 lbs. of ice build up, fell off the aircraft. I was real lucky that I didn't end up in the 32d water. Near freezing water makes the above picture's visibility all too common.
Yes, JAM, each year the Navy conducts polar exercises just to ensure that the capability doesn't atrophy.
And the seas are normally very rough also. I remember late one night trying to get a medevac off the back of a destroyer. It took about 10 minutes to finally syncronize the aircraft with the 30' pitching deck. When it was rising, I didn't have enough power to keep up with it and when it was falling, it fell faster than the aircraft at no power. Finally gave up chasing it and figured out if I stayed steady, the deck would rise up and meet me. Somehow I stayed aboard when it fell again.