Flash Flood in Guam
Every flash flood event the National Weather Service has filed in Guam, year by year, with the most significant episodes. Flooding that begins within six hours of the rain that causes it, or of a dam or levee failure or ice jam release, often with deadly speed.
The most significant on the map
The most significant flash flood episodes in Guam.
- Tornadoes
- Tropical storms and surge
- Floods
- Wind
- Hail
- Winter weather
- Heat and drought
- Cold
- Fire, smoke and dust
- Marine and coastal
- Other
The record
- Events
- 20
- Deaths
- 1
- Injuries
- 0
- Damage
- $6.8 million
Every year
The most significant
Ranked by deaths, injuries, damage and size together.
- Hurricane and Flash Flood in Guam, June 27 to 30, 2004TYPHOON TINGTINGAfter starting about 500 miles southeast of Saipan the evening of June 25th, Tropical Depression 11W moved steadily northwest, becoming Tropical Storm Tingting the following afternoon at 1600 SST.
- Flash Flood in Guam, July 30, 1999Flash flooding event in Merizo. Heavy rain from a nearly stationary thunderstorm caused flash flooding across a small section along the southern tip of Guam.
- Flash Flood in Guam, October 29 to 30, 2003Thunderstorms developed along an active monsoon trough that was in near Pohnpei. The showers started during the afternoon of the 29th and continued throughout the day. Thunderstorms moved across Pohnpei during the night.
- Flash Flood and Damaging Wind in Guam, November 23, 2020A brief period of severe thunderstorm winds and flooding occurred over the Marianas.
- Flash Flood and High Wind in Guam, September 16 to 17, 2024A strong winds associated with monsoon surge impacted the Marianas around September 16th as a monsoon depression (Invest 97W) developed and would later become Tropical Storm Pulasan in the Philippine Sea, west of the Marianas.
- Tropical Storm and Flash Flooding in Guam, September 9 to 13, 2024TS Bebinca originated in the Federated States of Micronesia near Pohnpei and Kosrae as a surface trough. Bebinca gradually consolidated into a closed low-level circulation as it moved WNW past Pohnpei and Chuuk as was monitored as Invest 95W.
- Flash Flood in Guam, September 15, 2002Around noon time heavy showers fell over Saipan. Tree trunks, vegetation, rocks and all sorts of debris washed down by water from the As Mahetog hill filled two northbound lanes in Saipan.
- Flash Flood and Flooding in Guam, October 11, 2022A monsoon trough, extending across the Philippines and into the Mariana Islands, brought periods of heavy rain to Guam leading to flooding during the morning of October 11th.
- Flash Flood and Flooding in Guam, January 8 to 11, 2023A shear line dropping south into the Marianas and interacting with a nearby trade-wind trough brought heavy rain to the Marianas. The WFO on Guam reported a 24 hour total of 2.97 inches on January 8th and a five day total from January 8th to January 12th of 7.56 inches.
- Flash Flooding in Guam, August 31, 2023A monsoon trough extended into the western waters of Guam and up and through Saipan.|Locally heavy showers developed within the trough and then moved over Guam during the afternoon hours of August 31st, causing flash flooding across the central portion of Guam.
- Flash Flood and Strong Wind in Guam, August 25 to 28, 2025The Intertropical Convergence Zone (ITCZ) developed across eastern Micronesia, producing areas of gusty winds and heavy rainfall, especially along embedded trade-wind troughs.
- Flash Flood in Guam, July 17, 2003From July 6th to 17th 15.56 inches fell at the National Weather Service Office in Palau. Periods of heavy rain during this time period caused a few landslides across Babeldaob.On the 17th hours of heavy rain caused a Japanese-era coral retaining wall to collapse in Ngerbeched.
- Flash Flood in Guam, July 31, 2003Light winds combined with daytime heating caused showers and thunderstorms to form across the island of Guam. The heaviest rain was over the southern portions of the island.
- Flash Flood in Guam, August 5, 2004Several days of heavy rain brought flash flooding to Saipan. At least four families were evacuated. Several roads were closed by water that was knee-deep in places.
- Flash Flood in Guam, October 19, 2005A nearly stationary thunderstorm dumped up to 5 inches of rain over the mountains and coastal areas of southwestern Guam from Agat south through Umatac to Merizo. Water and mud from the Talifak River entered a market in Agat and swept around several homes.
- Flash Flood in Guam, August 27, 2020A disturbance within a weak monsoon brought heavy to torrential rains to central and southern Guam, resulting in flash floods.
- Flash Flood in Guam, September 8, 2023A circulation developed southwest of the Marianas on September 6th and then lifted northwest, passing through the Marianas and was west of the Marianas by September 8th.
- Flash Flood in Guam, April 29, 2025Heavy rainfall across Pohnpei brought 3 to 5 inches across the island with most of the rain falling over a 4 to 5 hour period.
More
Sources
NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24.