Champi’s warnings end, but flooded-road risks and dangerous seas remain

Drivers in northern Guam still need to turn back at flooded roads, and swimmers across four Mariana Islands still face dangerous surf—even though Champi’s cyclone warnings have ended. A new flood advisory issued Monday, October 19, put northern Guam communities at risk from heavy rain hours after the broader regional flood watch was cancelled. The storm’s departure has brought relief, but not safety everywhere. ^{20 3}

At 12:58 p.m. Chamorro Standard Time Monday, the reporting cutoff for this account, that local flood advisory remained within its stated period, alongside surf, rip-current and small-craft alerts. The National Weather Service had cancelled the last Typhoon Warnings for Guam and Rota at 5:51 p.m. Sunday, October 18, explicitly ending tropical-cyclone watches and warnings throughout the Marianas and surrounding waters. Those cancellations did not end the separate local hazards. ^{20 260}

All three times are Chamorro Standard Time. They are scheduled product endpoints, not promises that a road, reef or stretch of coastal water becomes safe at that minute.

The northern Guam advisory, issued at 12:13 p.m., reported a radar-based estimate of 1.5 to 3 inches of rain already fallen in its area, with another 0.5 to 1.5 inches expected. These are local advisory-area amounts—not an island-wide gauge total or Champi’s full-storm rainfall. The additional rain remained a forecast. ²⁰

The advisory named Dededo, Tamuning, Yigo, Mangilao, Barrigada, Andersen Air Force Base and Mongmong-Toto-Maite. Urban areas and small streams faced flooding, with minor flooding expected in low-lying places and areas with poor drainage. The practical instruction was unambiguous: do not attempt to drive through flooded roads. ²⁰

That warning followed a genuine regional improvement. At 6:55 a.m., NWS forecasters said radar and satellite imagery showed Champi’s outer rainbands withdrawing, and cancelled the broader flood watch. The later northern Guam advisory does not contradict that assessment: it concerns a more localized threat at a later time. Rain can ease across a region while still falling hard enough in one part of it to cause trouble. ^{3 20}

Along exposed reefs, Monday’s forecast called for breaking waves of 9 to 11 feet, down from the previous evening’s 10 to 14 feet. The High Surf Advisory covered south- and west-facing reefs of Guam and Rota and south-facing reefs of Tinian and Saipan. High rip-current risk also covered the south and east reefs of Tinian and Saipan, as well as the south and west reefs of Guam and Rota. These were forecast surf conditions, not measurements of individual waves. ^{20 264}

Rip currents can sweep even strong swimmers offshore, and localized beach erosion remained possible. NWS advice for anyone caught in a current was to relax and float rather than fight it, swim parallel to the shoreline if able to escape, and call or wave for help if unable. Guam’s official notice announcing the return to normal readiness retained this instruction: ^{20 82}

Boating restrictions also survived a higher-level warning’s cancellation. The Hazardous Seas Warning ended, but a Small Craft Advisory continued across all four islands’ coastal waters. Guam and Rota had forecast seas of 10 to 12 feet and southeast winds of 15 to 20 knots; Tinian and Saipan had seas of 9 to 11 feet and winds of 10 to 20 knots. Both areas could see frequent gusts to 30 knots. Inexperienced mariners, especially those operating smaller vessels, were advised to avoid boating in those conditions. ²⁰

In our October 17 broadcast, aired at 20:45 UTC—early October 18 on Guam—we reported Champi at 140 mph, with Guam and Rota still under Typhoon Warnings. Super-typhoon intensity was not yet confirmed in that account. Subsequent NWS bulletins established the upgrade to 150 mph and, later Sunday, the cancellation of the remaining cyclone warnings. Those were successive stages of the storm, not competing descriptions of the same moment. ^{1 260}

The later bulletins also placed the eye’s closest passage about 10 miles south of Guam’s southern tip around 4:26 a.m. Sunday. That establishes a very close offshore passage, not a center landfall. The midday account described an eye around five miles wide. Champi’s maximum sustained wind within the storm was not the wind experienced at every village or at the airport. ^{1 8}

Guam International Airport had occasional gusts up to 80 mph Sunday morning. By the afternoon warning, airport observations showed sustained winds of 25 to 30 mph with frequent gusts up to 60 mph. Rota experienced verified tropical-storm conditions that morning; Saipan later had reported gusts up to 35 mph. Tinian and Saipan’s Tropical Storm Warnings and Typhoon Watches ended at midday, while Guam and Rota remained warned until evening. The islands did not experience identical conditions or recover on one common clock. ^{1 4 5 7}

Offshore, NWS reported destructive typhoon-force winds occurring in western Guam waters during Sunday’s warning period. Forecast significant seas could reach 24 feet near Guam and 20 feet near Rota. Those were potential offshore sea heights, not observed beach breakers or verified storm maxima. Later buoy observations of 9- to 12-foot combined seas came from the far northern Marianas—a different location that cannot settle how high seas reached near Guam. ^{6 3}

By Monday’s 7 a.m. position, Champi was about 345 miles west of Guam, moving west-northwest at 14 mph with maximum sustained winds of 140 mph. Its general course and speed were forecast to continue through Tuesday. Renewed super-typhoon strength later Monday remained a forecast, not an established outcome. The next public advisory was scheduled for 2 p.m. local time. ²⁶¹

Governor Lourdes Leon Guerrero returned Guam to Condition of Readiness 4 at 6 p.m. Sunday, ending the earlier shelter posture. The Pacific Daily News reported that an initial drive-through assessment found no significant ocean inundation, collapsed buildings, flooded-out or impassable roads, or mudslides along the assessment. That was reassuring early reconnaissance, not a completed island-wide damage inventory. ²⁶³

Contemporary Pacific Daily News reporting also described fallen trees and damaged roofs in southern Guam. Those localized reports were not accompanied by quantified losses or independent official confirmation. Neither they nor the early assessment establish the full toll, and no verified casualty count or comprehensive damage total is established here. Missing figures must not be read as zero harm. ²⁶⁷

Water operations show concrete disruption. As of 8 a.m. Sunday, 72 of Guam’s 98 operating production wells depended on standby generators. All sewer pump stations and wastewater treatment plants were online, and no sewer overflows had been reported at that point. Parts of Pago Bay, Malesso’ and Latte Heights had reported low or absent water pressure. These are dated operating conditions, not confirmation of household service on Monday. ²⁶⁵

Flood-related turbidity in the Ugum River forced the Ugum Surface Water Treatment Plant to be secured. Its reservoir remained unaffected and continued supplying the distribution system. Power and water crews were coordinating generator operations, while power fluctuations, refueling and servicing could require further adjustments. ²⁶⁵

Public-school students had no classes Monday while administrators and staff assessed facilities. School shelters continued operating and supporting occupants; elementary parent-teacher conferences were postponed, with replacement dates to come after reopening. Government operations reopened Monday, according to Guam’s official recovery notice, while officials assisted motorists and continued warning of possible flooding and life-threatening marine conditions. ^{263 82}

The remaining work is to establish actual restoration, losses and measured storm maxima—not simply to mark Champi farther away on a map. For now, the distinction that matters most is practical: normal readiness allows recovery to proceed; it does not make flooded roads passable or hazardous water safe.