The Sea Horror by Edmond Hamilton

Young Ernest Stevens, on that fateful night of the 7th which saw the climax of the world's fear, had found himself in the vicinity of Piccadilly when the first rush of the panic began. He had seen for himself the sudden rise of the waters of the Thames which had taken place during the preceding few days, and had also read the newspaper accounts of the extraordinary and unexplainable heightening of the sea's level, but was still so much centered on the strange passing of Clinton and his expedition as to give the subject of general interest but small attention. On this night, however, when the publication of that epochal last message from the Portsmouth station sent the first crowds hastening through the streets, Stevens realized his own position and started off across the city toward his lodgings.

Before he had gone far the first great mobs were rushing through the streets, beginning the vast exodus from the city, and disrupting all the ordinary means of transportation. Already, too, salt floods were creeping through the streets, adding to the panic of the crowds, and as Stevens walked on, the lights of the city around him were beginning to fail, fanning the flames of fear higher in the already panic-mad crowds. By the time Stevens finally stumbled up the steps of his lodging-house, the street on which it stood was wholly dark, and covered by a few inches of water through which the fugitives along its length were splashing.