Guam, 2022Flash Flood and Flooding in Guam, October 11, 2022
October 11, 2022 · NWS GUM · 4 events in 1 county or zone
A 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. Central and southern portions of Guam received on average 4 to 7 inches of rain between 0130ChST and 1400ChST, while northern portions of Guam received 1 to 3 inches of rain between 0300ChST and 1300ChST.
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- Deaths
- 0
- Injuries
- 0
- Property damage
- $500
- Crop damage
- None recorded
- Events
- 4
Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.
A 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. Central and southern portions of Guam received on average 4 to 7 inches of rain between 0130ChST and 1400ChST, while northern portions of Guam received 1 to 3 inches of rain between 0300ChST and 1300ChST. The peak of the heavy rainfall was between 0300ChST and 0600ChST, with an automated rain gage in southern Guam (near the village of Umatac) recording 0.72 inches in 15 minutes or an hourly rain rate of 2.88 inches.
Flash Flood, Guam
- When
- October 11, 2:50 AM GST to 7:40 AM GST
- Where
- Guam County, 1.7 mi NNE of Yona to 1.85 mi NNE of Yona
- Cause
- Heavy Rain
- Reported by
- River/Stream Gage
- Coordinates
- 13.422, 144.782
Heavy rainfall across central and southern portions of Guam caused ponding on roadways. Estimates of 4 to 6 inches fell across the Pago watershed. The Pago River gage showed Pago river starting at a height around 2 feet at 0250ChST quickly climbing to over 5 feet at 0315ChST, and peaking at 14.28 feet at 0505ChST before slowly decreasing and not dropping below 5 feet until 0740ChST. Route 4 near Pago Bay (located just north of the Pago River crossing) had reports of water over the road, and though it never officially closed, traffic stopped for a time as people felt passage was unsafe.
Flood, Guam
- When
- October 11, 3:00 AM GST to 10:00 AM GST
- Where
- Guam County, 1.91 mi ENE of Apra Harbor to 1.63 mi E of Apra Harbor
- Cause
- Heavy Rain
- Reported by
- Public
- Coordinates
- 13.436, 144.678
Heavy rainfall across central and southern portions of Guam caused ponding on roadways. Via group chats and social media, the office received reports of water covering the northbound lanes of Route 1 (called locally as Marine Corps Drive) near Polaris Point, located south of the village of Piti. The Mount Chachao rain gage near Piti reported a total of 4.69 inches with 2.89 inches falling between 0245ChST and 0530ChST.
Flood, Guam
- When
- October 11, 3:00 AM GST to 10:00 AM GST
- Where
- Guam County, 1.64 mi SE of Merizo to 1.65 mi SE of Merizo
- Cause
- Heavy Rain
- Property damage
- $500
- Reported by
- Public
- Coordinates
- 13.255, 144.689
Heavy rainfall across central and southern portions of Guam caused ponding on roadways. Rain gages across southern Guam showed about 4 to 7 inches fell during the morning hours. A bridge located where Joutan Lane meets up with Route 4 had water over the road and debris was piled up along the side of the bridge and road. Removal of debris is estimated to cost about $500.
Flood, Guam
- When
- October 11, 7:40 AM GST to 11:36 AM GST
- Where
- Guam County, 1.71 mi NNE of Yona to 1.85 mi NNE of Yona
- Cause
- Heavy Rain
- Reported by
- River/Stream Gage
- Coordinates
- 13.422, 144.782
Heavy rainfall across central and southern portions of Guam caused ponding on roadways. Estimates of 4 to 6 inches fell across the Pago watershed. The Pago River gage showed Pago river starting at a height around 2 feet at 0250ChST quickly climbing to over 5 feet at 0315ChST, and peaking at 14.28 feet at 0505ChST before slowly decreasing and not dropping below 5 feet until 0740ChST. Route 4 near Pago Bay (located just north of the Pago River crossing) had reports of water over the road, and though it never officially closed, traffic stopped for a time as people felt passage was unsafe. Moderate rainfall then kept Pago river between 4 and 5 feet from 0740ChST to 1135ChST as the Route 4 near Pago Bay still had ponding on the road, but traffic was moving and improving at this time.
- Flash Flood
- 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.
- Flood
- Flooding that develops more slowly than a flash flood: rivers leaving their banks, or water standing over land for an extended time.
After NWS Directive 10-1605, the rules offices file Storm Data by.
- Drought in Minnesota, October 11 to 31, 2022$2.6 million · 2 events
- Drought in Iowa, October 11 to 31, 2022$295,000 · 1 event
- Hail and Damaging Winds in Nebraska, October 11 to 12, 20221 in hail · 10 events
- High Wind in Montana, October 11 to 12, 202256 kt wind · 7 events
- Drought in Texas, October 11 to 31, 20224 events
- Drought in Arkansas, October 11 to 31, 20224 events
- Drought in Nebraska, October 11 to 31, 20223 events
- Drought in Missouri, October 11 to 31, 20223 events
- Flash Flood and Heavy Rain in California, October 11 to 12, 20223 events
- Heavy Rain in Hawaii, October 11 to 13, 20223 events
- Drought in Alabama, October 11 to 31, 20222 events
- High Wind in Wyoming, October 11, 202253 kt wind · 2 events
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 2026-09-30. Each event’s entry at NCEI: 1062086, 1061909, 1062054, 1062088.