Guam, Northern Mariana Islands High Surf Warning | Effective 04/14/2026 05:40

* WHAT...For the Coastal Flood Warning, significant coastal flooding. For the High Surf Warning, dangerously large breaking waves of 11 to 16 for Guam, 15 to 20 feet for Rota, and 20 to 30 feet for Tinian and Saipan. * WHERE...All reefs of Tinian and Saipan. South, west, and north facing reefs of Guam and Rota * WHEN...For the Coastal Flood Warning, until 5 AM ChST Thursday. For the High Surf Warning, until 6 PM ChST Thursday. * IMPACTS...Numerous roads may be closed. Low lying property including homes, businesses, and some critical infrastructure will be inundated. Some shoreline erosion will 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. * ADDITIONAL DETAILS...As STY Sinlaku crosses the Marianas over or near Tinian and Saipan, swell and highest surf will shift toward the north and west. This will maintain dangerous surf and coastal inundation as STY Sinlaku continues through the Marianas tonight through Wednesday. Inundation has been reported on Guam and in Saipan. Tinian and Saipan could see wave and wind driven surf push water on to land up to 10 to 15 feet higher than the water- level, especially along windward facing beaches and shores.