Coastal Flood Watch Guam, Northern Mariana Islands | Effective 03/14/2026 23:07

* WHAT...Large breaking waves of 9 to 12 feet, are expected to build up to 16 feet along north facing reefs by as early as Monday morning. Dangerous rip currents. For the Coastal Flood Watch, significant coastal flooding is possible. * WHERE...Guam, Rota, Tinian and Saipan. * WHEN...For the High Surf Warning, until 5 AM ChST Tuesday. For the Coastal Flood Watch, through late Monday night. For the High Rip Current Risk, through late Monday night. * 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...Lastest altimetry pass shows elevated sea heights for the islands of Pagan northward. Looking further north on altimetry, sea heights are showing 16 to 20 feet. This is due to strong winds around a vigorous low pressure system near Japan and a Kona Low that is northwest of Hawai'i, which have been producing long-period NNW and NE swells in the region. Hazardous surf and a high risk of rip currents are expected along north and east facing reefs. Surf is expected to build to around 16 feet along north facing reefs, therefore, a High Surf Warning has been issued. Advisory level surf will continue along east facing reefs. As NNW swell builds over the coming days, it could potentially build to hazardous levels of 9 feet along west facing reefs, likely requiring the advisory to be extended to west facing reefs. The coastal flooding along north facing reefs could reach 1 to 3 feet. Once the seas crest and begin to fall, lesser advisory conditions will still apply.