§ Of Túrin Turambar The Silmarillion

Then Túrin sped back to Nargothrond, mustering such of the rout as he met with on the way; and the leaves fell from the trees in a great wind as they went, for the autumn was passing to a dire winter. But the host of the Orcs and Glaurung the Dragon were there before him, and they came suddenly, ere those that were left on guard were aware of what had befallen on the field of Tumhalad. In that day the bridge over Narog proved an evil; for it was great and mightily made and could not swiftly be destroyed, and the enemy came readily over the deep river, and Glaurung came in full fire against the Doors of Felagund, and overthrew them, and passed within.