The last roaring is part of a magnificent image of Beorn:

The roar of his voice was like drums and guns; and he tossed wolves and goblins from his path like straws and feathers. He fell upon their rear, and broke like a clap of thunder through the ring.

• 01.079 The pines were roaring on the height,
• 07.099 and like a tide it roared and rolled;
• 10.006 like a distant roar.
• 12.021 roaring like thunder underground,
• 12.029 with a noise like a roaring wind.
• 12.031 they could hear the roar of the flying dragon grow
• 12.101 they heard the roar
• 14.011 before the roar of Smaug’s terrible approach grew loud,
• 14.013 Roaring he swept back over the town.
• 14.024 The lake roared in.
• 17.040 Winter thunder on a wild wind rolled roaring up
• 17.051 there rose from across the valley a deep-throated roar.
• 18.023 The roar of his voice was like drums