From what I've noticed is that the abominations seem to get more active during night time.

So if you really want to avoid them, keep an eye out at the sun and the cold / warm notifications in the top right corner.
The moment you see "cold" popping up, find yourself some shelter to last the night.

What I did in the swamp was heading out there in the "afternoon", so I could enter a sunken crypt close to nightfall, work my way through there during the night and return to my base near dawn. That way I still had to deal with the "regular" monsters, but at least avoided the aboninations.

Thorin :)