Surface Observation stations on ice
 

One thing that does not seem to have been considered much is the possibility of
useing outposts and patrols stationed on the ice itself to search for subs. Just drive along, dig a hole where it's thin enough and drop a sonobuoy in. Or something similar.

It would only work in the Antarctic area. Places like the Ross Ice Shelf. You cannot put one in the Arctic. Why? It's nothing but a floating, MOVING, chunk of ice. You put a station there and it will end up in the North Atlantic by the end of the year.

SOSUS arrays deployed on the seabed beneath the ice would stand in for this pretty well I think. I have it on good authority that arrays have been tested/deployed in the Arctic circle with positive results.

Depends where on the ice pack you put it. Not all the ice melts in the summer, it just recedes somewhat. If you put it near the North Pole it would be quite safe.

Nemo