"But upon the eighth day dark clouds overspread the heavens. There followed the muttering of thunder and the flash of lightning. Soon large drops of rain began to fall. The world had never witnessed anything like this, and the hearts of men were struck with fear. All were secretly inquiring, “Can it be that Noah was in the right, and that the world is doomed to destruction?” Darker and darker grew the heavens, and faster came the falling rain. The beasts were roaming about in the wildest terror, and their discordant cries seemed to moan out their own destiny and the fate of man. Then “the fountains of the great deep” were “broken up, and the windows of heaven were opened.” Water appeared to come from the clouds in mighty cataracts. Rivers broke away from their boundaries, and overflowed the valleys. Jets of water burst from the earth with indescribable force, throwing massive rocks hundreds of feet into the air, and these, in falling, buried themselves deep in the ground. PP 99.1"
"In the six hundredth year of Noah’s life, in the second month, the seventeenth day of the month, the same day were all the fountains of the great deep broken up, and the windows of heaven were opened."
EGW directly quotes Genesis 7:11.
"The people first beheld the destruction of the works of their own hands. Their splendid buildings, and the beautiful gardens and groves where they had placed their idols, were destroyed by lightning from heaven, and the ruins were scattered far and wide. The altars on which human sacrifices had been offered were torn down, and the worshipers were made to tremble at the power of the living God, and to know that it was their corruption and idolatry which had called down their destruction. PP 99.2"
"And they shall go into the holes of the rocks, and into the caves of the earth, for fear of the Lord, and for the glory of his majesty, when he ariseth to shake terribly the earth."
Both passages describe destruction and fear in the face of God's power, although the specific events differ.
"impenitent will know just where and what their sin is—the despising of His holy law. Yet they will have no more true repentance than did the old-world sinners. PP 99.3"
"But after thy hardness and impenitent heart treasurest up unto thyself wrath against the day of wrath and revelation of the righteous judgment of God;"
Both passages discuss the concept of an impenitent heart and the consequences thereof. While not a direct quote, the thematic overlap is significant.