Coastal Flood Watch Guam, Northern Mariana Islands | Effective 03/16/2026 11:19

* WHAT...Large breaking waves of 10 to 13 feet, up to 15 feet along north facing reefs. Dangerous rip currents. Possible coastal inundation along northern shorelines. * WHERE...West, north, and east facing reefs of the Marianas. For the Coastal Flood Watch, northern shorelines. * WHEN...For the High Surf Warning and Coastal Flood Watch, until 4 PM ChST this afternoon. For the High Surf Advisory, from 4 PM this afternoon to 4 PM ChST Wednesday. For the High Rip Current Risk, through Wednesday afternoon. * IMPACTS...Some roads may be closed. Low lying property may be inundated. Some shoreline erosion may occur. Breaking waves can sweep people off jetties and docks, and into dangerous seas. Life-threatening swimming conditions and significant beach erosion can be expected. Rip currents can sweep even the best swimmers away from shore into deeper water. * ADDITIONAL DETAILS...Long period NNW swell from a low pressure system near Japan and long-period NE swell from a Kona Low northwest of Hawai'i continue to produce hazardous surf and a high risk of rip currents along west, north, and east facing reefs. The main concern will be north facing reefs, where surf can reach up to 15 feet through this afternoon. Hazardous surf of at least 9 feet along west and north reefs, and of at least 12 feet along east facing reefs will continue through at least Wednesday afternoon. Surf is expected to first fall below hazardous levels along west facing reefs as the westerly component of the primary swell energy diminishes. Coastal inundation along northern shorelines of 1 to 3 feet is possible through this afternoon.