The last thing the narrator sees as he flees the home is the house being split in two. A whirlwind then collapses the house and the small lake (tarn) swallowing up the remains.

The closing lines read:

While I gazed, this fissure rapidly widened --there came a fierce breath of the whirlwind --the entire orb of the satellite burst at once upon my sight --my brain reeled as I saw the mighty walls rushing asunder --there was a long tumultuous shouting sound like the voice of a thousand waters --and the deep and dank tarn at my feet closed sullenly and silently over the fragments of the "HOUSE OF USHER."