The personification of the storm enhances the conflict because it creates suspense, as Brian has recently faced the moose and his defenses are low.
By this point, Brian is successful at getting food. A moose attacks him while he is getting more food. In addition to being frightened, Brian also injures his shoulder and ribs. He manages to get back to his shelter and falls asleep. That is when the storm wakes him.
The fear of the storm on top of the shock and pain of the moose attack is almost more than Brian can take.
Low, almost alive, almost from a throat somehow, the sound, the noise was a roar, a far-off roar but coming at him and when he was fully awake he sat up in the darkness, grimacing with pain from his ribs (Chapter 16).
This description of the storm increases suspense. The reader feels sorry for Brian and wonders what more this poor kid can take. He was practically starving, and is attacked when doing his best to get food. The attack frightens him, but he doesn't even have time to recover because of the storm. Like the moose, the storm is a new, unfamiliar obstacle and Brian doesn’t know what will happen.
He found the spear and bow where they were hanging on the pegs of the shelter wall and brought his weapons to the bed he had made of pine boughs. More comfort, but like the comfort of the flames it didn't work with this new threat that he didn't understand yet (Chapter 16).
Brian feared the wind might be a tornado. He was not prepared for the intense wind that "whipped against the front wall of the shelter like a rag." Still, Brian survives this incident like all of the others.