Leaning against the tree, he stuck the blunt of his forward facing spears into the snow, pointing out and away from his body and pressed up against the roots of the tree. Able to keep moving, yes, but this was a good spot to catch his breath and try to get his bearings. So far he hadn't been menaced by anything, so collecting himself was important.

He flipped the backwards facing spears forward, so all four spears were propped out and away from his body. Two supported by the tree and two in his hands. Removing the wooden plank he dropped it forward and dug it into the snow, piling up a small hill of it around the base so it would provide some kind of wall to keep snow from piling up on him directly. 

Completely immobilizing himself and planting himself firmly in one spot, LeeRoy used his boots to push away as much of the snow as possible and provide even more of a dugout between his spears and shield. Not much of a protection from anything except wind and snow, but regular dirt under his boots felt more comfortable than snow.