August 1903 Tsunami: Cook Inlet, AK, United States
A tsunami caused by a volcano began at Cook Inlet, AK, United States in August 1903. Its effects were recorded at 1 place.
Where the waves reached
The source (white) and every runup with a place, colored by the water height recorded there. A ring is a runup NCEI marks doubtful.
- Under 1 m
- 1 to 3 m
- 3 to 10 m
- 10 to 30 m
- 30 m and more
- Height not recorded
The tsunami
- Date
- August 1903
- Source
- Cook Inlet, AK, United States
- Cause
- Volcano
- Runups recorded
- 1
- Waters
- Ocean
- How certain
- Questionable tsunami
The toll
The record gives no deaths, injuries or damage for this tsunami.
What the record says
NCEI’s account, from the sources it cites.
Waves were seen in the calm Iniskin Bay; there are reports of a mudflow following the partial collapse of a caldera. It is speculated that a continuing process, such as a volcanic activity, produced the disturbance. (Ref #239)
Every runup
Nearest the source first. Heights are above sea level at the time; a tide gauge reads half the wave’s full height.
| Where | Country | Km from source | Water height, m | Inland, m | Measured by | First wave, UTC | Deaths |
|---|---|---|---|---|---|---|---|
| Iniskin Bay, AK, AK | United States | Eyewitness observation of water height |
More
Every tsunami in 1903The 1900sTsunamis of United StatesAlerts in force
Sources
Tsunami events and runups from NOAA’s National Centers for Environmental Information, Global Historical Hazard Database, cited as NCEI/WDS, doi:10.7289/V5PN93H7. Public domain. Read 2026-09-24. NCEI tsunami event 1297.