July 26, 1856 Tsunami: Unimak Island, AK, United States

1856, July 26. There was a volcanic eruption in Unimak Pass. None of the effects describe organized wave action, and this is probably not a tsunami report. Validity 1 (Reference #239).

1856, July 26. There was a violent eruption in Unimak Pass, apparently near 54 deg 35 min N., 165 deg W. It is described by Neville, the captain of the whaler "Alice Fraser." Crossing the pass on his ship with six other whalers, he observed that as a result of the volcanic eruption, enormous masses of dense black smoke were rising over the conical peaks of the mountains on the adjacent islands. He and the captains of the other whalers made ready to round the eastern tip of Unalaska Island, in order to get a good look at the eruption, which was accompanied by a prolonged dull roar and tremors, which by that time they had already felt repeatedly. At precisely this instant, the strong breeze which had been blowing completely died down, and the ships found themselves at the mercy of the eruption, in danger of being run aground. The eruption, lasting several hours with variable intensity, then appeared to reach its climax. The thunder of the eruption and the underground rumble rapidly intensified and became ever more ominous. The air was so still that dense black smoke was ejected straight up into the sky, without deviating in the slightest. It spread out above, at cloud level, and ashes, like flakes of snow, fell down in abundance. After 12 hours of still, a light breeze arose from the south, enabling the ships to move away from the volcano. But this breeze carried the column of smoke to the water surface, and a pitch darkness set in over a distance, as was later established, of more than 180 km, and the ships lost sight of the shore. The ashes fell like snow in a blizzard, covering the ships with gray substance from the deck to the top of the masts, blinding and choking all those on deck. Sailing west and north of the eastern shore, the ships tore out of the cloud of smoke. When they were near the northern base of the volcano, a prolonged dull rumble pealed out under them, and an underwater eruption occurred almost right in the centre of the flotilla. First the water churned and began to rise stormily in the form of disorderly waves. Then it rushed up, as if ejected from an enormous spring, forming a dazzling column of water of colossal height, which gradually disintegrated. Then a shaft of fire and smoke rose from the bottom upwards with peals of thunder. Lava and stones from a walnut to a cannon ball in size were disgorged, and fell on deck. This lasted no more than an instant, and the eruption ended as quickly as it had began. The water rushed into the abyss which had formed, forming a colossal whirlpool. The noise was like Niagara Falls. The ships rushed to safety, leaving the volcano in a state of regular alternation of relative calm and eruptions. This event is mentioned very briefly in a number of publications (Reference #414).