Severe Storm Surge ● Monitoring
Coastal Flood Warning issued October 17 at 10:25AM ChST until October 19 at 4:00AM ChST by NWS Tiyan GU, United States of America
Loading live data… · Marker positions are approximate; severity is labelled in each popup. Sources: USGS, GDACS, NASA EONET, NOAA/NWS, EMSC.
* WHAT...For the Coastal Flood Warning, significant coastal
flooding expected. For the High Surf Warning, dangerously large
breaking waves up to 35 feet for Guam, 20 to 25 feet for Rota,
and 15 to 20 feet for Tinian and Saipan.
* WHERE...Guam, Rota, Tinian and Saipan.
* WHEN...From 5 PM this afternoon to 4 AM ChST Monday.
* IMPACTS...Numerous roads may be closed. Low-lying property
including homes, businesses, and some critical infrastructure will
be inundated. Shoreline erosion will occur. Breaking waves can
sweep people off their feet, and into dangerous seas. Life-
threatening swimming conditions and significant beach erosion can
be expected. Coastal inundation of 5 to 7 feet for Guam, 2 to 4
feet for Rota and 1 to 3 feet for Tinian and Saipan is possible
along with coastal flooding and beach erosion.
* ADDITIONAL DETAILS...Surf is expected to rise rapidly to dangerous
levels tonight. Coastal impacts to the western coast of Guam and
Rota are highly dependent on the final track of Champi; passage
south of Guam would be reduced impacts whereas passage over Guam
would result in larger coastal inundation.
Measurements
| Coordinates | 39.9645, -100.8105 |
|---|---|
| Region | Guam; Rota; Tinian; Saipan |
| Location Precision | country |
| Issuing Authority | United States of America — us-noaa-nws-en |
| Cap Urgency | Expected |
| Cap Certainty | Likely |
| Cap Expires | 2026-10-17T18:00:00+10:00 |
Official source
Warnings courtesy of the issuing national meteorological service, via the WMO Alert Hub.
This is an official warning issued by the authority named above. Follow its instructions and those of your local emergency services.
Severity as published by WMO Alert Hub (national weather services).
View original reportThis event as JSON · API and licence
Source updated 2 days ago (Oct 17, 2026 00:26 UTC) · we last heard from WMO Alert Hub (national weather services) 22 seconds ago
On a slow connection? Low-bandwidth version — no map, no scripts, under 14 KB.
Internet connectivity at the time
Internet connectivity in United States dropped 24 hours after this event, and stayed disrupted for about 1 hour.
From 18 Oct 2026 00:00 UTC to 18 Oct 2026 01:00 UTC. Detected by active probing — networks that stopped answering.
Internet outages have many causes — damaged cables, power failures, network maintenance and deliberate shutdowns among them. IODA detects the loss of connectivity and does not attribute it to anything. This is shown because it happened at the same time, not because one caused the other.
Measured by IODA, Georgia Institute of Technology.
About this location
The agency did not publish coordinates for this warning. The pin is the centre of the country, not the location of the event — read the area name, not the map, for where it applies.
Area as the agency stated it: Guam; Rota; Tinian; Saipan
Official authorities in United States
If you are there, these are the bodies whose instructions apply. This site is not an emergency service and does not issue warnings.
More for United States →What to do
Follow the instructions issued by WMO Alert Hub (national weather services) and your local emergency services. The guidance below is background.
Understanding surge zones, evacuation timing, and why storm surge is the deadliest part of a tropical cyclone.
Open Storm Surge Safety Guide →Earlier storm surge events in United States
Severe and extreme events of the same kind, before this one. Listed for scale, not because they are connected to it.
Nearby & related events
Disclaimer: figures are automatic feeds from the named agencies and may be revised. Do not use this page for life-safety decisions — follow official local emergency services.