Flood Watch in Effect for Guam
Issued: September 21, 2026 — 4:22 p.m. ChST
The Guam Homeland Security/Office of Civil Defense (GHS/OCD) advises residents that the National Weather Service (NWS) Tiyan has issued a Flood Watch for Guam, in effect from Tuesday morning, September 22, through Wednesday evening, September 23, 2026. Flash flooding caused by excessive rainfall is possible.
Current Status
Forecast guidance shows 2 to 5 inches of rain during the watch period. Many locations across Guam have already received 2 to 4 inches of rain since Saturday, and soils remain wet from heavy rainfall over the past couple of weeks. This lowers the threshold for flash flooding over the next couple of days.
Flooding is possible in rivers, creeks, and streams, in poor drainage and urban areas, and at low-water crossings.
What You Should Do Now
Residents are advised to take the following precautions:
- Monitor later forecasts from the National Weather Service.
- Be prepared to take action should Flash Flood Warnings be issued.
For the latest official weather information, visit the National Weather Service at weather.gov/gum. For preparedness information, visit ghs.guam.gov or contact GHS/OCD at 475-9600.
Media Contact:
Logan Reyes, Acting Public Information Officer
Guam Homeland Security / Office of Civil Defense
logan.reyes@guam.gov