Describe the night on which the fall of the House of Usher actually happens?

On the night the House of Usher "falls", a storm rages outside and the Narrator is too terrified to sleep, he and Usher sit together in a bedroom and read from the "Mad Trist" by Sir Launcelot Canning.

In the final lines, the narrator describes the effects of the storm; "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 and 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.'"

From the text:

"The impetuous fury of the entering gust nearly lifted us from our feet. It was, indeed, a tempestuous yet sternly beautiful night, and one wildly singular in its terror and its beauty. A whirlwind had apparently collected its force in our vicinity; for there were frequent and violent alterations in the direction of the wind; and the exceeding density of the clouds (which hung so low as to press upon the turrets of the house) did not prevent our perceiving the lifelike velocity with which they flew careering from all points against each other, without passing away into the distance. I say that even their exceeding density did not prevent our perceiving this--yet we had no glimpse of the moon or stars--nor was there any flashing forth of the lightning. But the under surfaces of the huge masses of agitated vapor, as well as all terrestrial objects immediately around us, were glowing in the unnatural light of a faintly luminous and distinctly visible gaseous exhalation which hung about and enshrouded the mansion."