NOAA NWS / Event history

Coastal Flood Warning issued October 17 at 4:31PM ChST until October 19 at 4:00AM ChST by NWS Tiyan GU

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

See what changed ↓Detailed event record ↗

Bulletin issued: 17 October 2026 at 06:31 UTC
First saved by us: 16 October 2026 at 21:32 UTC
Last included in a daily record: 17 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; Tinian; Saipan
Certainty / urgency: Likely / Expected
Message expiry (not hazard end): 17 October 2026 at 20:45 UTC
Forecast onset / end: 17 October 2026 at 07:00 UTC / 18 October 2026 at 18:00 UTC

Archived official description

* 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 coasts 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.

Instructions in this archived message

Everyone should remain out of the water due to life-threatening surf conditions. Stay well away from the coast.

The saved record

What changed

2 updates · 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 2 changes

Saved by us
17 October 2026 at 06:32 UTC
Version 3
6 recorded details changed
Title
Before
Coastal Flood Warning issued October 17 at 10:25AM ChST until October 19 at 4:00AM ChST by NWS Tiyan GU
After
Coastal Flood Warning issued October 17 at 4:31PM ChST until October 19 at 4:00AM ChST by NWS Tiyan GU
Source updated
Before
17 October 2026 at 00:25 UTC
After
17 October 2026 at 06:31 UTC
Effective from
Before
17 October 2026 at 00:25 UTC
After
17 October 2026 at 06:31 UTC
Message expiry
Before
17 October 2026 at 08:00 UTC
After
17 October 2026 at 20:45 UTC
Official description
Before
* 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 wher…
After
* 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 coasts of Guam and Rota are highly dependent on the final track of Champi; passage south of Guam would be reduced impacts wher…
External source link
Before
https://api.weather.gov/alerts/urn:oid:2.49.0.1.840.0.58ebf6d80599ddfeb9999acccb0023f3e5416414.001.1
After
https://api.weather.gov/alerts/urn:oid:2.49.0.1.840.0.feb770b8581b3efc978be6ec518cc3cc4b268f89.001.1
Bulletin issued: 17 October 2026 at 06:31 UTC
View saved version 3
Original saved fields, unchanged. This is our record, not an archived copy of the external webpage.
{ "id": "nws:30b84663331028640240fd75", "authorityId": "urn:oid:2.49.0.1.840.0.feb770b8581b3efc978be6ec518cc3cc4b268f89.001.1", "sender": "w-nws.webmaster@noaa.gov", "references": [ { "identifier": "urn:oid:2.49.0.1.840.0.26b913b2029babcc0badbd23a5bea62d86323f19.001.2", "sender": "w-nws.webmaster@noaa.gov" }, { "identifier": "urn:oid:2.49.0.1.840.0.58ebf6d80599ddfeb9999acccb0023f3e5416414.001.1", "sender": "w-nws.webmaster@noaa.gov" } ], "category": "weather", "title": "Coastal Flood Warning issued October 17 at 4:31PM ChST until October 19 at 4:00AM ChST by NWS Tiyan GU", "eventType": "Coastal Flood Warning", "occurredAt": "2026-10-17T06:31:00.000Z", "issuedAt": "2026-10-17T06:31:00.000Z", "timeBasis": "Bulletin issued", "effectiveAt": "2026-10-17T06:31:00.000Z", "onsetAt": "2026-10-17T07:00:00.000Z", "expiresAt": "2026-10-17T20:45:00.000Z", "forecastEndAt": "2026-10-18T18:00:00.000Z", "severity": "Severe", "urgency": "Expected", "certainty": "Likely", "messageType": "Update", "status": "Source update", "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 flooding\nexpected. For the High Surf Warning, dangerously large breaking\nwaves up to 35 feet for Guam, 20 to 25 feet for Rota, and 15 to 20\nfeet for Tinian and Saipan.\n\n* WHERE...Guam, Rota, Tinian and Saipan.\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 1 to 3 feet for Tinian and Saipan is possible\nalong with coastal flooding and beach erosion.\n\n* ADDITIONAL DETAILS...Surf is expected to rise rapidly to dangerous\nlevels tonight. Coastal impacts to the western coasts of Guam and\nRota are highly dependent on the final track of Champi; passage\nsouth of Guam would be reduced impacts whereas passage over Guam\nwould result in larger coastal inundation.", "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.feb770b8581b3efc978be6ec518cc3cc4b268f89.001.1", "source": "nws", "sourceName": "NOAA NWS" }
Visit the external source ↗
The external page may have changed since this version was saved.

Saved by us

17 October 2026 at 00:32 UTC

Version 2

Source status changed

Title: Before
Coastal Flood Warning issued October 17 at 7:26AM ChST until October 19 at 4:00AM ChST by NWS Tiyan GU
After
Coastal Flood Warning issued October 17 at 10:25AM ChST until October 19 at 4:00AM ChST by NWS Tiyan GU
Source updated: Before
16 October 2026 at 21:26 UTC
After
17 October 2026 at 00:25 UTC
Effective from: Before
16 October 2026 at 21:26 UTC
After
17 October 2026 at 00:25 UTC
Message expiry: Before
17 October 2026 at 13:00 UTC
After
17 October 2026 at 08:00 UTC
Message type: Before
Alert
After
Update
Source status: Before
Source alert
After
Source update
Official description: Before
* 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 Mo…
After
* 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 Mo…
External source link: Before
https://api.weather.gov/alerts/urn:oid:2.49.0.1.840.0.26b913b2029babcc0badbd23a5bea62d86323f19.001.2
After
https://api.weather.gov/alerts/urn:oid:2.49.0.1.840.0.58ebf6d80599ddfeb9999acccb0023f3e5416414.001.1

Bulletin issued: 17 October 2026 at 00:25 UTC

View saved version 2

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

{
  "id": "nws:09d72697e956cbf9c7684898",
  "authorityId": "urn:oid:2.49.0.1.840.0.58ebf6d80599ddfeb9999acccb0023f3e5416414.001.1",
  "sender": "w-nws.webmaster@noaa.gov",
  "references": [
    {
      "identifier": "urn:oid:2.49.0.1.840.0.26b913b2029babcc0badbd23a5bea62d86323f19.001.2",
      "sender": "w-nws.webmaster@noaa.gov"
    }
  ],
  "category": "weather",
  "title": "Coastal Flood Warning issued October 17 at 10:25AM ChST until October 19 at 4:00AM ChST by NWS Tiyan GU",
  "eventType": "Coastal Flood Warning",
  "occurredAt": "2026-10-17T00:25:00.000Z",
  "issuedAt": "2026-10-17T00:25:00.000Z",
  "timeBasis": "Bulletin issued",
  "effectiveAt": "2026-10-17T00:25:00.000Z",
  "onsetAt": "2026-10-17T07:00:00.000Z",
  "expiresAt": "2026-10-17T08:00:00.000Z",
  "forecastEndAt": "2026-10-18T18:00:00.000Z",
  "severity": "Severe",
  "urgency": "Expected",
  "certainty": "Likely",
  "messageType": "Update",
  "status": "Source update",
  "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 the High Surf Warning, dangerously large\nbreaking waves up to 35 feet for Guam, 20 to 25 feet for Rota,\nand 15 to 20 feet for Tinian and Saipan.\n\n* WHERE...Guam, Rota, Tinian and Saipan.\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 1 to 3 feet for Tinian and Saipan is possible\nalong with coastal flooding and beach erosion.\n\n* ADDITIONAL DETAILS...Surf is expected to rise rapidly to dangerous\nlevels tonight. Coastal impacts to the western coast of Guam and\nRota are highly dependent on the final track of Champi; passage\nsouth of Guam would be reduced impacts whereas passage over Guam\nwould result in larger coastal inundation.",
  "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:2.49.0.1.840.0.58ebf6d80599ddfeb9999acccb0023f3e5416414.001.1",
  "source": "nws",
  "sourceName": "NOAA NWS"
}

Visit the external source ↗

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

First saved record · 16 October 2026 at 21:32 UTC

Saved by us

16 October 2026 at 21:32 UTC

Starting point

First saved record

Our first saved version of Coastal Flood Warning issued October 17 at 7:26AM ChST until October 19 at 4:00AM ChST by NWS Tiyan GU. We have no earlier saved version to compare.

Bulletin issued: 16 October 2026 at 21:26 UTC

View saved version 1