Tropical Storm · Guam

Super Typhoon Sinlaku passed north of Guam and Rota and passed near or over Tinian and Saipan on April 15. Tropical storm winds started 1900ChST April 13 and ended just before 1300ChST April 16. Strong westerly tropical storm winds were recorded on Guam. The Apra Harbor Tide Gauge recorded a max wind of 58 mph at 1100ChST April 14 with a gust of 74 mph at 0155ChST April 15. Guam International Airport reported sustained winds of 55 mph at 2255ChST April 14 with a max gust of 87 mph at 1542ChST April 14. Pago Bay Tide Gauge reported a max water level of 2.03 feet (MHHW) at 0612ChST April 14. Lowest pressure measure on Guam was 976.0 mb (MSLP) at the Dandan RAWS near Inalhan at 2200ChST April 14. NWS Storm Survey around Guam saw extensive coastal inundation. On the east side of Guam near Talo'fo'fo, coastal run-up to 15.67 feet was recorded as the likely absolute max, with 5.50 ft and 9.00 ft of coastal run-up measured at Inalhan. On the west side of Guam 9.58 ft to 10.85 feet was measured at Asan, near the War in the Pacific Park. This flooding pushed sand up and across to Route 1 (Marine Corp Drive), along the stretch of road from Asan and northward to near Hagta, the capital of Guam. Ritidian on the northwest tip of Guam saw coastal run-up to 11.20 ft. Two indirect deaths were reported on Guam as an elderly pair were found dead due to carbon monoxide poisoning due to a generator running indoors after the storm passed. Crop damage was estimated to be around 2 million USD and property damage estimated around 434.5 million USD on Guam.

What eventually became Super Typhoon Sinlaku (04W) originally crossed the Date Line at 4N around March 29, with a circulation at 4.2N 179.5E. This circulation would struggle to organize as it drifted westward and the circulation would redevelop south of Kosrae on April 4 near 2N164E.By 0000 UTC on April 6, Invest 90W had formed south-southwest of Pohnpei/southeast of Chuuk near 4.5N 159.8E. By April 8th the new circulation had lifted northwest to a position northeast of Chuuk. At 0200 UTC on April 9th 90W was upgraded from sub-low to Medium by JTWC. Aided by a strong westerly wind burst of 30 to 35kt, by 1800 UTC on the 9th of April a Tropical Cyclone Formation Alert was issued for 90W as it continued to rapidly organize. By 1200 UTC on the April 9, 90W became Tropical Depression (TD) 04W as it drifted slowly west to a position north of Chuuk (roughly 50 miles north). By 0000 UTC on April 10, 04W was upgraded to Tropical Storm (TS) Sinlaku (04W) and was located roughly 70 miles northwest of Chuuk. AT 0000 UTC on the April 10, TS Sinlaku was located at 8.2N 151.2E, at 08:22 UTC, there was a voluntary ship ob of westerly winds at 30 KT at 5.87N 147E., and westerly winds of 35kt at 2.1N 158.1E. By 0000 UTC on the April 11, Sinlaku became a typhoon (TY), nearly stationary about 80 miles northwest of Chuuk. Sinlaku continued to meander in the area as it strengthened northwest of Chuuk, becoming a super typhoon (STY) by 0000 UTC April 12. STY Sinlaku continued to strengthen as it moved north then northwest toward the Marianas. Sinlaku continued to move slowly NW with maximum sustained winds of 175 MPH on the 12th. At 1140 UTC on April 14 the western edge of the eye wall impacted Tinian and Saipan. The wind field continued to expand with Sinlaku, resulting in the maximum sustained wind and maximum gust occurring on April 14th in Guam. Sinlaku continued to move through the Marianas slowly, maintaining TS warning for Guam for 4 days. Sinlaku turned north, then north-northeast, affecting the islands of Alamagan, Pagan and Agrihan in the far northern CNMI. Sinlaku finally moved out of the northern CNMI on April 18. Sinlaku became an extratropical cyclone on April 20, 2026. There were 17 deaths (direct and indirect) and 6 injuries associated with STY Sinlaku. Nine fatalities (7 direct/2 indirect or unknown) and direct 5 injuries were reported in Chuuk State. For the Mariana Islands, 2 indirect deaths were reported on Guam, while 6 direct deaths and 1 injury was reported in the CNMI. Chuuk State government estimate home and crop damages total around 96 million USD. On Guam, estimate 434.5 million USD damage to public property and 2 million USD for crop losses. Initial estimates from FEMA estimate damage cost exceed 1 billion USD across the CNMI.