Hurricane in Guam, August 22 to 24, 2004

TYPHOON CHABATropical Depression 19W began about 35 miles northeast of Enewetak early on the morning of August 19th, and became Tropical Storm Chaba that evening 110 miles northwest of Enewetak. Chaba moved west-northwest, then west over the next two days, and was upgraded to a typhoon late on the 21st, about 350 miles east of the Mariana Islands. From that point, Typhoon Chaba moved almost straight west and intensified steadily, moving through the Mariana Islands between Rota and Tinian at about 2230 SST the evening of the 22nd with maximum sustained winds of 145 mph. Chaba brought typhoon conditions to Rota and Tinian, and tropical storm conditions to Guam and Saipan. Heavy rain and minor flooding occurred on all the islands.Guam: At Guam International Airport, the highest sustained wind, 48 mph, was recorded at 2254 SST on the 22nd. The peak gust was 66 mph from the southwest, at 2248 SST on the 22nd, and again at 0318 SST on the 23rd. The highest sustained wind anywhere on the island was 58 mph from the west-northwest at Andersen AFB, at 1929 SST on the 22nd. The automated station at Apra Harbor reported the highest gust, 79 mph from the southwest, at 0451 SST on the 23rd. The greatest 24-hour rainfall was at the airport, where 8.89 inches fell in the 24 hours ending at 0600 SST on the 23rd. Heavy rain continued over the next two days, bringing the 3-day total for the 22nd-24th to 12.95 inches. The lowest observed sea-level pressure on the island was 991.6 mb at Andersen AFB at 2355 SST on the 22nd. Rota: Chaba's 50-mile-diameter eye passed 25 miles north-northeast of Rota at about 2230 SST on the evening of the 22nd, keeping the 10-mile-thick eyewall over the island for several hours. The highest sustained wind and peak gust reported by the automated station at Rota Airport were 66 mph and 136 mph, both on the observation for 2051 SST on the 22nd. The sustained wind value is likely too low, based on reports of sustained winds less than 10 mph in the next few hours while the eyewall was over Rota. A noteworthy feature of Chaba's passage over Rota is that gusts of 100 mph or more were registered on ten consecutive hourly observations, from 1951 SST on the 22nd to 0451 SST on the 23rd. Following the 136 mph gust at 2051 SST, the following 5 hours had peak gusts of 132 mph, 129 mph, 135 mph, 133 mph and 135 mph.The automated station at the airport recorded 12.26 inches of rain in the 24 hours ending at 0451 SST on the 23rd. Another 8.54 inches of rain fell between 0200 SST and 1800 SST on the 24th. The lowest reported sea-level pressure was 952.8 mb at 2351 SST on the 22nd.Tinian: The observer at Tinian Airport does not report rainfall or sea-level pressure, and is only there part-time. The highest reported sustained wind and peak gust were 58 mph and 81 mph, both from the northeast at 1950 SST on the 22nd. After that time, the observing station was closed for the night. Saipan: At Saipan International Airport, the maximum sustained wind was 62 mph from the southeast at 2257 SST on the 22nd. The peak gust, 70 mph from the southeast, occurred a little earlier at 2205 SST. In the 24 hours ending at 0354 SST on the 23rd, 6.33 inches of rain fell. The lowest sea-level pressure was 985.6 mb at 2254 SST on the 22nd. Pagan Island: The automated station on Pagan recorded a maximum sustained wind of 39 mph from the east-southeast at 1300 SST on the 22nd, and a peak gust of 70 mph from the east later that afternoon at 1600 SST. The lowest sea-level pressure of 999.4 mb occurred the following day, at 1500 SST on the 23rd. In the 24 hours ending at 1000 SST on the 23rd, Pagan recorded only 0.57 inches of rain. STORM EFFECTS AND DAMAGEGuam: Coastal inundation was reported up to 6 feet, but it caused no significant damage. One person was swept over the reef and drowned the day after the typhoon, and 4 minor injuries were reported. Beach erosion was light, and only minor flooding resulted from the heavy rain. No major damage was reported from the high winds. Rota: Damage was extensive, with over 50 homes totally destroyed and over 175 suffering major damage. Many power poles and line were blown down, resulting in an island-wide power outage. Vegetation, trees and crops were also heavily damaged. Coastal inundation of 8 to 11 feet resulted in heavy beach erosion. There were no fatalities, and only a few minor injuries reported. Tinian/Saipan: Coastal inundation was reported at 6 to 8 feet, resulting in moderate beach erosion. The day before the typhoon, a man was swept over the reef and drowned. About 270 homes were destroyed on the two islands, with over 700 suffering major damage. Falling trees damaged several cars on Saipan. Many power lines were downed, resulting in island-wide power outages. On Tinian, telephone service was also knocked out. Crops suffered major damage.Alamagan/Pagan/Agrihan: No injuries or significant damage were reported. Total damage from Typhoon Chaba is estimated at $18,000,000.