User blog comment:IamJakuhoRaikoben/Chapter 463: Black Carpet, Review./@comment-24546844-20151123122516/@comment-7418318-20151123161356

We've seen the other Dragons annihilate enitre mountains with their Roars, so I think we can pretty savely assume that Igneel in his prime could have reshaped the landscape far more than the groove that Natsu made.

Besides... just 970 something soldiers? With that tight a formation that isn't much in terms of affected area... at least not compared to Dragon-scale attacks.