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Coastal Flood Warning issued October 18 at 12:00PM ChST until October 19 at 4:00AM ChST by NWS Tiyan GU

Coastal Flood Warning · Guam; Rota. Severe; likely; urgency: expected.

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Bulletin issued: 18 October 2026 at 02:00 UTC
First saved by us: 17 October 2026 at 22:02 UTC
Last included in a daily record: 18 October 2026
The linked daily edition preserves what we captured that UTC day; this event page is not a live warning.
Source classification: Severe · Source update

A recent feed check does not mean a new observation. This page preserves source records; it does not establish current safety or warning status.

Issuer / area: NWS Tiyan GU · Guam; Rota
Certainty / urgency: Likely / Expected
Message expiry (not hazard end): 18 October 2026 at 16:00 UTC
Forecast onset / end: 18 October 2026 at 02:00 UTC / 18 October 2026 at 18:00 UTC

Archived official description

* WHAT...For the Coastal Flood Warning, significant coastal flooding. For the High Surf Warning, dangerously large breaking waves of 18 to 24 feet in the surf zone. * WHERE...Guam and Rota. * WHEN...Until 4 AM ChST Monday. * IMPACTS...Low lying property including homes, businesses, and some critical infrastructure may still be inundated. Some shoreline erosion will occur. Breaking waves can sweep people off jetties and docks, and into dangerous seas. Life-threatening swimming conditions and significant beach erosion can be expected. * ADDITIONAL DETAILS...South to southeast swells and elevated wind waves induced by Super Typhoon Champi to the west-southwest will continue life-threatening surf and significant coastal flooding at least through early Monday morning.

Instructions in this archived message

Everyone should remain out of the water due to life-threatening surf conditions. Stay off of jetties, piers, and other waterside infrastructure.

The saved record

What changed

1 update · 1 first record

Each update compares two versions we saved. This may not include every update from the source. A missing report does not mean an event has ended.

Showing 1 change

Saved by us
18 October 2026 at 02:02 UTC
Version 2
Source status changed
Title
Before
Coastal Flood Warning issued October 18 at 7:55AM ChST until October 19 at 4:00AM ChST by NWS Tiyan GU
After
Coastal Flood Warning issued October 18 at 12:00PM ChST until October 19 at 4:00AM ChST by NWS Tiyan GU
Source updated
Before
17 October 2026 at 21:55 UTC
After
18 October 2026 at 02:00 UTC
Effective from
Before
17 October 2026 at 21:55 UTC
After
18 October 2026 at 02:00 UTC
Forecast onset
Before
17 October 2026 at 21:55 UTC
After
18 October 2026 at 02:00 UTC
Message expiry
Before
18 October 2026 at 13:00 UTC
After
18 October 2026 at 16:00 UTC
Message type
Before
Alert
After
Update
Source status
Before
Source alert
After
Source update
Reported area
Before
Guam; Rota; Tinian; Saipan
After
Guam; Rota
Source summary
Before
Coastal Flood Warning · Guam; ~~Rota; Tinian; Saipan.~~ Severe; likely; urgency: expected.
After
Coastal Flood Warning · Guam; Rota. Severe; likely; urgency: expected.
Official description
Before
* WHAT...For the Coastal Flood Warning, significant coastal flooding expected for south and east facing shorelines. For the High Surf Warning, dangerously large breaking waves up to 30 feet for Guam, 20 to 25 feet for Rota, and 15 to 20 feet for Tinian and Saipan. * WHERE...South and east facing reefs of 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 2 to 4 feet for Tinian and Saipan is possible along with coastal flooding and beach erosion. * ADDITIONAL DETAILS...Dangerous surf from the southeast will continue the next day or so.
After
* WHAT...For the Coastal Flood Warning, significant coastal flooding. For the High Surf Warning, dangerously large breaking waves of 18 to 24 feet in the surf zone. * WHERE...Guam and Rota. * WHEN...Until 4 AM ChST Monday. * IMPACTS...Low lying property including homes, businesses, and some critical infrastructure may still be inundated. Some shoreline erosion will occur. Breaking waves can sweep people off jetties and docks, and into dangerous seas. Life-threatening swimming conditions and significant beach erosion can be expected. * ADDITIONAL DETAILS...South to southeast swells and elevated wind waves induced by Super Typhoon Champi to the west-southwest will continue life-threatening surf and significant coastal flooding at least through early Monday morning.
Official instructions
Before
Everyone should remain out of the water due to life-threatening surf conditions. Stay ~~well away from the coast.~~
After
Everyone should remain out of the water due to life-threatening surf conditions. Stay off of jetties, piers, and other waterside infrastructure.
External source link
Before
https://api.weather.gov/alerts/urn:oid:2.49.0.1.840.0.0e7432c5597c80a0ee84b9e5d0142f777255ff18.001.1
After
https://api.weather.gov/alerts/urn:oid:2.49.0.1.840.0.df1eac139d63bdf17a9b6aac1e2a573bfb896cb1.002.1
Bulletin issued: 18 October 2026 at 02:00 UTC
View saved version 2
Original saved fields, unchanged. This is our record, not an archived copy of the external webpage.
{ "id": "nws:7339781ad83d69327bb4ecd3", "authorityId": "urn:oid:2.49.0.1.840.0.df1eac139d63bdf17a9b6aac1e2a573bfb896cb1.002.1", "sender": "w-nws.webmaster@noaa.gov", "references": [ { "identifier": "urn:oid:2.49.0.1.840.0.0e7432c5597c80a0ee84b9e5d0142f777255ff18.001.1", "sender": "w-nws.webmaster@noaa.gov" } ], "category": "weather", "title": "Coastal Flood Warning issued October 18 at 12:00PM ChST until October 19 at 4:00AM ChST by NWS Tiyan GU", "eventType": "Coastal Flood Warning", "occurredAt": "2026-10-18T02:00:00.000Z", "issuedAt": "2026-10-18T02:00:00.000Z", "timeBasis": "Bulletin issued", "effectiveAt": "2026-10-18T02:00:00.000Z", "onsetAt": "2026-10-18T02:00:00.000Z", "expiresAt": "2026-10-18T16:00:00.000Z", "forecastEndAt": "2026-10-18T18:00:00.000Z", "severity": "Severe", "urgency": "Expected", "certainty": "Likely", "messageType": "Update", "status": "Source update", "place": "Guam; Rota", "coordinates": null, "issuer": "NWS Tiyan GU", "summary": "Coastal Flood Warning · Guam; Rota. Severe; likely; urgency: expected.", "description": "* WHAT...For the Coastal Flood Warning, significant coastal flooding.\nFor the High Surf Warning, dangerously large breaking waves of 18\nto 24 feet in the surf zone.\n\n* WHERE...Guam and Rota.\n\n* WHEN...Until 4 AM ChST Monday.\n\n* IMPACTS...Low lying property including homes, businesses, and some\ncritical infrastructure may still be inundated. Some shoreline\nerosion will occur. Breaking waves can sweep people off jetties and\ndocks, and into dangerous seas. Life-threatening swimming\nconditions and significant beach erosion can be expected.\n\n* ADDITIONAL DETAILS...South to southeast swells and elevated wind\nwaves induced by Super Typhoon Champi to the west-southwest will\ncontinue life-threatening surf and significant coastal flooding at\nleast through early Monday morning.", "instruction": "Everyone should remain out of the water due to life-threatening\nsurf conditions. Stay off of jetties, piers, and other waterside\ninfrastructure.", "url": "https://api.weather.gov/alerts/urn:oid:2.49.0.1.840.0.df1eac139d63bdf17a9b6aac1e2a573bfb896cb1.002.1", "source": "nws", "sourceName": "NOAA NWS" }
Visit the external source ↗
The external page may have changed since this version was saved.

First saved record · 17 October 2026 at 22:02 UTC

Saved by us

17 October 2026 at 22:02 UTC

Starting point

First saved record

Our first saved version of Coastal Flood Warning issued October 18 at 7:55AM ChST until October 19 at 4:00AM ChST by NWS Tiyan GU. We have no earlier saved version to compare.

Bulletin issued: 17 October 2026 at 21:55 UTC

View saved version 1

Original saved fields, unchanged. This is our record, not an archived copy of the external webpage.

{
  "id": "nws:9421d847aac9ca3e8e234ef4",
  "authorityId": "urn:oid:2.49.0.1.840.0.0e7432c5597c80a0ee84b9e5d0142f777255ff18.001.1",
  "sender": "w-nws.webmaster@noaa.gov",
  "references": [],
  "category": "weather",
  "title": "Coastal Flood Warning issued October 18 at 7:55AM ChST until October 19 at 4:00AM ChST by NWS Tiyan GU",
  "eventType": "Coastal Flood Warning",
  "occurredAt": "2026-10-17T21:55:00.000Z",
  "issuedAt": "2026-10-17T21:55:00.000Z",
  "timeBasis": "Bulletin issued",
  "effectiveAt": "2026-10-17T21:55:00.000Z",
  "onsetAt": "2026-10-17T21:55:00.000Z",
  "expiresAt": "2026-10-18T13:00:00.000Z",
  "forecastEndAt": "2026-10-18T18:00:00.000Z",
  "severity": "Severe",
  "urgency": "Expected",
  "certainty": "Likely",
  "messageType": "Alert",
  "status": "Source alert",
  "place": "Guam; Rota; Tinian; Saipan",
  "coordinates": null,
  "issuer": "NWS Tiyan GU",
  "summary": "Coastal Flood Warning · Guam; Rota; Tinian; Saipan. Severe; likely; urgency: expected.",
  "description": "* WHAT...For the Coastal Flood Warning, significant coastal\nflooding expected for south and east facing shorelines. For the\nHigh Surf Warning, dangerously large breaking waves up to 30 feet\nfor Guam, 20 to 25 feet for Rota, and 15 to 20 feet for Tinian and\nSaipan.\n\n* WHERE...South and east facing reefs of Guam, Rota, Tinian and\nSaipan.\n\n* WHEN...From 5 PM this afternoon to 4 AM ChST Monday.\n\n* IMPACTS...Numerous roads may be closed. Low-lying property\nincluding homes, businesses, and some critical infrastructure will\nbe inundated. Shoreline erosion will occur. Breaking waves can\nsweep people off their feet, and into dangerous seas. Life-\nthreatening swimming conditions and significant beach erosion can\nbe expected. Coastal inundation of 5 to 7 feet for Guam, 2 to 4\nfeet for Rota and 2 to 4 feet for Tinian and Saipan is possible\nalong with coastal flooding and beach erosion.\n\n* ADDITIONAL DETAILS...Dangerous surf from the southeast will\ncontinue the next day or so.",
  "instruction": "Everyone should remain out of the water due to life-threatening\nsurf conditions. Stay well away from the coast.",
  "url": "https://api.weather.gov/alerts/urn:oid:2.49.0.1.840.0.0e7432c5597c80a0ee84b9e5d0142f777255ff18.001.1",
  "source": "nws",
  "sourceName": "NOAA NWS"
}

Visit the external source ↗

The external page may have changed since this version was saved.