Coastal Flood — Marshall Islands, Guam

2024-01-20 · Marshall Islands, Guam

Event narrative

Roi-Namur, one of the islands within the Kwajalein Atoll, experience very large surf, with some witness reports claiming waves exceeding 20 feet, with videos on land showing water of 3 to 4 feet hitting and washing through the Army's dining hall on Roi-Namur. The event was described as a series of 4-6 waves that occurred over the course of 30-45 minutes, that occurred between 2020-2100LST (1820-1900 ChST) on January 20th, with waters quickly receding after the last large wave. Eighty people were evacuated to Kwajalein Island, with one person treated for injuries at the clinic on Kwajalein Island and no deaths reported. Aerial damage assessment conducted by the Army showed that inundation washed over the northwest side of the island, flooding at least one-third of it, with standing water on both sides of the north end of the runway and the first floors of all but two bachelors' quarters. No subsequent inundation episodes were reported on Roi, even during high tide at 0052LST and 1342LST on January 21st. Other Islands within the Marshall Islands reported some moderate inundation such as Woja in Ailinglaplap Atoll, were some erosion stretch from the shore line to the airfield, with debris was also tossed onto airfield. Minor inundation was reported at Arno atoll (located just east of Majuro) and Kili Island, home of the displaced Bikini Islanders. Damage estimates are still ongoing, but the International Federation of Red Cross and Red Crescent Societies (IFRC) had an initial estimate of 55 Thousand USD at the end of January, but total damage cost may end up being much higher.

Wider weather episode

A distant but powerful extratropical cyclone passing well north of Micronesia, created a long period north swell that traveled through the region. It generated very high surf and led to quick and extensive coastal flooding within the Republic of the Marshall islands and parts of Micronesia. The swell also moved into the southern hemisphere with some impacts being reported across the Samoan Islands.

Source: NOAA Storm Events Database, event_id 1159315. Narrative written by the NWS forecast office that issued the report.