November 4, 1994 Tsunami: Skagway, AK, United States

Reference #11889:

At 7:10 p.m. on November 3, 1994, a large tsunami generated by a massive landslide in the submerged Skagway River delta occurred near Skagway, Alaska, resulting in one fatality and damaging or destroying many harbor structures. At first, ‘it was theorized by some that construction activity in the harbor caused the initial landslide. However, this paper presents the findings of an in-depth scientific investigation that concludes that such a theory is impossible. The findings paint a clear picture of the failure of the submerged Skagway River delta that was overloaded by flood sediments and exacerbated by river diking. Slide volumes estimated at over 20,000,000 cubic yards that consisted of a massive initial slide and subsequent retrogressive earth slides produced the tsunami that caused the fatality and destroyed or damaged harbor structures.

Reference #1315:

A negative tide of 1.2 m at 7:10 pm local time was the probable cause of a submarine landslide-generated tsunami that caused about $25 million damage and one fatality in Skagway Harbor, Alaska. It produced a tsunami of nine to eleven meters. Because the event was not associated with an earthquake, there was about a year delay before the tsunami community became aware of the event.

Reference #234:

The landslide was accompanied by a series of large-amplitude, high frequency sea level oscillations estimated by eyewitnesses to be 5-6 m in height in the inlet and 9-11 m at the shoreline.

Reference #11885:

On November 3, 1994, at about 7:10 p.m., a tsunami wave with a period of about 3 minutes and maximum height of 25 to 30 feet occurred in the Taiya Inlet at Skagway, Alaska as reported by Lander(1). The event occurred at the time of a low tide of 4 feet below lower low level. The tidal range at Skagway is about 25 feet.

Reference #12143:

This report by an eyewitness, remote from the work site, confirms two things: 1) the drawdown (trough), not a crest, occurred first in upper Taiya Inlet; and 2) a change in air mass movement (wind) occurred before the drawdown reached the small boat harbor.

The "wall of water" which came northward toward the end of the old north dock, appeared to come over the tops of the tail wall sheet piles as they disappeared, hence a slide at the construction site could not have caused the “wall of water.”

Since the tide level was -5 feel MLLW at the time, the wave crest was approximately 30 feet above the tide elevation.

The seafloor surveys taken before and after the event disclose that about 23 million cubic yards of material slid or flowed in the upper Taiya Inlet during the November 3, 1994 seafloor instability, which lasted only seconds.