1958 Alaska Tsunami: Lituya Bay Rockslide and 1,720-Foot Wave

The 1958 Alaska tsunami at Lituya Bay was a landslide-generated megatsunami that sent water 1,720 feet up a mountainside, the highest tsunami runup ever recorded. It began at 10:16 p.m. on July 9, 1958, when a magnitude 7.8 earthquake on the Fairweather Fault shook roughly 40 million cubic yards of rock loose from the steep northeast wall of Gilbert Inlet, at the head of the bay. The rock plunged into deep water. Within minutes, the wave had scoured four square miles of forest down to bedrock, carried a fishing boat over a sand spit into the open ocean, and sunk another, killing the two people aboard.

The Earthquake and the Rockslide

The quake ruptured about 125 miles of the Fairweather Fault along the southeast Alaska coast, from Palma Bay to Icy Bay.¹ Its epicenter lay on the northern coast of Cross Strait near Palm Bay, at a focal depth of about 35 kilometers, and the shaking was felt across more than 650,000 square kilometers, from Seattle to Whitehorse.²

Inside Lituya Bay, the shaking triggered a massive rockfall above Gilbert Inlet, the arm at the head of the bay. The rock mass dropped from a maximum altitude of about 3,000 feet into the water below.³ The impact sheared 1,300 feet of ice off the front of Lituya Glacier and wiped out a stream delta inside the inlet.¹

How the Water Reached 1,720 Feet

The displaced water surged up the slope opposite the slide to a maximum altitude of 1,740 feet. The destruction line below that point, where the forest was stripped to bare rock, reached 1,720 feet.³ Around most of the rest of the bay, the trimline stood at roughly 700 feet.⁴

That figure describes runup, not open-water wave height. A wall of water 1,720 feet tall did not move through the bay. The energy of the slide hurled water up the fjord wall to that elevation; the gravity wave that traveled outward through the main body of the bay was estimated at 100 to 150 feet high and moved between 97 and 130 miles per hour. Survivor Howard Ulrich put it plainly: “The wave did not go up 1,800 feet, the water splashed there.”³

Later laboratory work by Hermann Fritz and colleagues, using a 1:675 scale model of Gilbert Inlet, replicated the trimline and confirmed an incident wave height of roughly 160 meters inside the inlet at an impact velocity near 110 meters per second.⁵ The experiments showed the rapid impact drove a large air cavity into the water, displacing far more volume than the rock alone, which helps explain the extreme height.¹

Fewer than five minutes passed between the earthquake and the wave reaching the fishing boats anchored in the outer part of the bay. In that time, the wave stripped four square miles of shoreline, taking trees up to four feet in diameter and the soil beneath them.¹

The Boats in the Bay

Three fishing vessels were anchored in the outer bay that evening, each with two people on board.

Howard and Sonny Ulrich on the Edrie

Howard Ulrich and his seven-year-old son Sonny were aboard the trolling boat Edrie. After about a minute of violent shaking, Ulrich heard a “great roar” from the head of the bay and saw what looked like “an explosion of water” in Gilbert Inlet.¹ His anchor was stuck. He let out all the remaining chain, told his son to put on a life preserver and pray, and tried to motor into the oncoming wave.

The wave broke on the left side of Cenotaph Island, the small island mid-bay, but ran smooth on the right. Ulrich steered into the smooth face. The Edrie climbed the wave; the anchor chain snapped and whipped around the pilothouse; the boat crested and slid down the back.¹ Looking down over the stern, Ulrich saw treetops far below the boat and believed that was where they would end up. The engine kept running. Around 11:00 p.m., father and son navigated through a chop filled with logs and ice and escaped through the entrance of the bay. Howard Ulrich died in 2014.⁶

Bill and Vivian Swanson on the Badger

Bill and Vivian Swanson, aboard the Badger, were lifted by the wave and carried over La Chaussee Spit, the narrow strip of land at the bay’s entrance, and deposited into the open ocean on the far side. Bill Swanson described the Badger lodged bow-first near the crest, as if surfing backwards, with treetops visible far below. The boat was wrecked on the ocean side of the spit, but the Swansons got into a skiff and were picked up shortly after midnight.¹

Orville and Mickey Wagner on the Sunmore

Orville and Mickey Wagner, a young couple from Idaho Inlet near Juneau, were aboard the 44-foot troller Sunmore.⁷ The wave swamped and sank their boat near the bay entrance. An oil slick marked where the Sunmore had been. Neither the Wagners nor the vessel were ever recovered.¹

Damage and Deaths Beyond the Bay

The megatsunami itself stayed inside Lituya Bay, but the earthquake caused damage across a wide stretch of southeast Alaska. At Yakutat, the only permanent settlement in the epicentral region, the quake took down bridges, damaged docks and oil lines, and toppled a water tower.² On Khantaak Island in Yakutat Bay, an 800-foot section of beach slumped into the sea and three people died.¹ Underwater landslides cut the Alaska Communication System submarine cable in Lynn Canal, and minor damage was reported in Juneau, Sitka, and other towns. A climbing party at 11,300 feet on Mount St. Elias felt the ground roll in waves and watched avalanches bury their lower camp.

All five confirmed deaths occurred in the water: the two Wagners inside Lituya Bay and the three people on Khantaak Island.¹ The toll was low only because the shoreline the wave hit was essentially uninhabited.

Why Lituya Bay

Lituya Bay is a narrow, T-shaped fjord about seven miles long on the outer coast of Alaska’s Glacier Bay region. The combination of recently glaciated steep slopes, heavily fractured rock, deep water, an active fault running directly through the bay, heavy rainfall, and frequent freeze-thaw cycles makes it uniquely prone to landslide-generated waves. The 1958 event was the largest, not the first.

USGS geologist Don J. Miller, who had been studying the bay’s hazards before 1958, used tree-ring dating of trimlines along the shore to identify at least four earlier giant-wave events:

1853 or 1854: a wave reaching 395 feet, likely from a slide at Mudslide Creek on the south wall.³
About 1874: a wave reaching roughly 80 feet.³
1899: a wave reaching about 200 feet, possibly tied to the great earthquakes of September 1899. A separate account says the event destroyed a native village on Cenotaph Island and killed five people.³⁴
1936: a wave reaching 490 feet, generated in Crillon Inlet. Witnesses reported three waves of increasing height in close succession, traveling about 22 miles per hour.³

Miller concluded that such waves were “likely to occur again.”³ Scientific analysis suggests a giant wave strikes the bay roughly once every 25 years.⁴ His definitive account of the 1958 event, USGS Professional Paper 354-C, “Giant Waves in Lituya Bay, Alaska,” was published in 1960.

Could It Happen Again

Lituya Bay sits within Glacier Bay National Park and Preserve, which receives more than 700,000 visitors a year, most of them traveling by water.⁸ The hazards that produced the 1958 wave have not gone away. The Alaska Earthquake Center has noted that landslide-generated tsunamis are “especially difficult disasters to prepare for” because technology-based warning systems cannot work quickly enough to help people only a few miles from the source.¹ The primary defense is recognizing the signs of a slide and moving to higher ground immediately.

Southeast Alaska keeps producing these events. On October 17, 2015, roughly 180 million tons of rock collapsed into Taan Fiord, an arm of Icy Bay about 80 miles from Lituya Bay, producing a tsunami with a peak runup of 633 feet, the fourth-highest ever recorded. The area was uninhabited and no one was killed. Scientists linked the slide to a century of rapid glacial retreat, decades of ground cracking, heavy rainfall, and minor shaking from a distant earthquake.⁹ Glaciologist Chris Larsen said that as climate change drives further retreat, the ice buttressing steep mountain slopes disappears, leaving oversteepened rock faces more prone to collapse.¹⁰

In August 2025, the NOAA ship Rainier conducted the first comprehensive bathymetric survey of Lituya Bay since 1959, mapping 15.5 square miles of seafloor over five days. The data showed dramatic change: the head of the bay, previously charted at depths up to 129 meters, has filled with sediment and is now dry land, and in places the floor is as much as 130 meters shallower than the old charts showed. During the survey, a separate landslide near Tracy Arm, 150 miles away, triggered a 15-foot tsunami.⁸

1
Alaska Earthquake Center. 60 Years Ago: The 1958 Earthquake and Lituya Bay Megatsunami
2
NOAA National Centers for Environmental Information. Significant Earthquake Information
3
USGS. Giant Waves in Lituya Bay, Alaska (Professional Paper 354-C)
4
NASA Earth Observatory. Lituya Bay’s Apocalyptic Wave
5
AGU Publications. Hybrid Modeling of the Mega-Tsunami Runup in Lituya Bay After Half a Century
6
Alaska’s News Source. Fault Facts: The World’s Largest Tsunami Was in Our Backyard
7
ExploreNorth. Lituya Bay Tsunami
8
NOAA. Rainier in Lituya Bay
9
National Park Service. The 2015 Taan Fiord Landslide and Tsunami
10
University of Alaska Fairbanks Geophysical Institute. Giant Wave in Icy Bay