Definition of "awfulest"

It's the awfulest city that ever I saw.

1872, Sophia May (Rebecca Sophia Clarke), Little Folks Astray‎

The awfulest thing was the silence; there wasn't a sound but the screaking of the saddles, the measured tramplings, and the sneezing of the horses, afflicted by the smothering dust-clouds which they kicked up.

1896, Samuel Clemens, Personal Recollections of Joan of Arc‎