Seatus was meditating, earlier he swam all the way across the Delaware river. He knew Brontes was present, he heard the rumors believing they were true, he had to find him later. Seatus wasn't bothered by cold water, he was in antarctica many times. Swimming beneath the ice caps with pods of the whales he created. This was during his God years, before he was usurped. 

Now Seatus sat at the bottom of the lake. His eyes were shut and legs crossed meditating, listening to the movements of the water. The sound of cracking ice interrupted him, he swam up to the sound punching the ice to make a hole to peek out. Seatus said "Meditation time's over I guess." he swam back under the sheet approaching closer to shore where the sheet of ice ended. He stepped out drenched from cold water, he shook it off and walked through the snow barefooted. He found a christmas charity box with clothes all inside it, he took a pair of jeans, t-shirt and a sweatshirt. He placed on the hood keeping himself  hidden walking down the path, he didn't know if any of the other Gods which could've likely been present, or Brontes would remember him he had a handsome human appearance now instead of a sea monster.