While the ski poles might be ineffective due to the T-Rex having stubby T-Rex arms, I think that it’s tail would allow for remarkable steering abilities !
From the snowman’s perspective, I think it might not need to be scared because theoretically it should be able to react to damage much like the bad Terminator in Terminator 2. He’s surrounded by his base materials after all..... he could either disintegrate and blend in to hide or alternatively he could take a dive and roll into a massive size that would scare off the T-Rex by utterly dwarfing it.