# OC Coastal High Tides: Flood Advisory and Metrolink OC Line Suspension

> The Metrolink Orange County Line suspension between Laguna Niguel/Mission Viejo and Oceanside ended as scheduled after Aug. 14, 2026, with weekend service planned as normal; tides have eased (Aug. 15 forecast peak 5.2 ft at Newport Bay) and no new NWS advisory or tidal damage has been reported. The acute event is resolved; OCTA's San Clemente riprap work and its September Coastal Commission emergency-permit review continue as a long-term coastal-rail track.

- Canonical: https://ocint.app/situation/oc-coastal-high-tide-metrolink-2026-08
- Markdown: https://ocint.app/situation/oc-coastal-high-tide-metrolink-2026-08.md
- JSON: https://ocint.app/api/situations/oc-coastal-high-tide-metrolink-2026-08
- Status: archived
- As of: 2026-08-17T03:02:24.051+00:00
- Started: 2026-08-07T17:00:00+00:00
- Cities: Dana Point, Huntington Beach, Laguna Beach, Laguna Niguel, Newport Beach, San Clemente, Seal Beach
- Publisher: OCINT (https://ocint.app)

## Who / What / Where / When / Why

**Who:** NWS San Diego (advisory authority); Metrolink and Amtrak (transit operators); OCTA (coastal track maintenance); OC coastal communities and rail riders.
**What:** King tide cycle produced minor coastal flooding along OC beaches Aug. 9–13; Metrolink suspended OC Line service south of Laguna Niguel/Mission Viejo Aug. 10–14 due to forecast high-tide risk to the coastal rail corridor.
**Where:** Orange County coastal cities (Seal Beach, Huntington Beach, Newport Beach, Laguna Beach, Dana Point, San Clemente) and the LOSSAN rail corridor south of Laguna Niguel/Mission Viejo station to Oceanside.
**When:** Tidal cycle began Aug. 9; NWS Coastal Flood Advisory ran Aug. 10–12; Metrolink suspension Aug. 10–14; advisory expired, suspension lifted, and tidal peaks easing as of Aug. 14–15.
**Why:** An astronomical king tide alignment produced the highest predicted tidal peaks of the year along the Southern California coast, threatening low-lying coastal infrastructure including the LOSSAN rail right-of-way near sea level.

## Narrative

## Current Status

The Metrolink Orange County Line suspension between Laguna Niguel/Mission Viejo and Oceanside **ended as scheduled after Aug. 14**, with no extension reported. According to Metrolink's [Upcoming Advisories page](https://metrolinktrains.com/train_status/upcoming-advisories/), the OC Line suspension is listed only for Aug. 10–14; the next listed closures concern the Antelope Valley Line. The [NWS San Diego Coastal Flood Advisory](https://api.weather.gov/alerts/urn:oid:2.49.0.1.840.0.1a67094b37b807b9c0d2a9969989c4af1ff2d643.001.1) expired after 11 PM PDT Aug. 12 and has not been reissued. NOAA data shows the Aug. 15 Newport Beach forecast peak falling to **5.2 ft** — a marked decline from the 6.6–6.9 ft peaks recorded at the cycle's height. A High Tide Alert was still logged at Newport Beach in the early hours of Aug. 15, but tidal activity is now easing toward background levels consistent with the close of this astronomical cycle.

## Flooding Scope

The advisory window documented minor coastal flooding during evening high tides each night, with peaks ranging from **6.6 ft (Aug. 9) to 6.9 ft (Aug. 10 and Aug. 12)** and advisory projections reaching 7.2–7.5 ft. NWS identified impacts including inundation of low-lying parking lots, parks, and roadways along the OC coast. The Aug. 13 king tide forecast of 6.5 ft and the subsequent Aug. 14 forecast of 5.9 ft confirmed a steady decline from peak levels, consistent with the astronomical alignment weakening. No structural damage or injuries have been reported in available evidence.

## Transit Impact

Metrolink suspended Orange County Line service south of Laguna Niguel/Mission Viejo beginning Aug. 10, citing forecast high-tide risk to the coastal rail corridor. Trains originated and terminated at Laguna Niguel/Mission Viejo for the duration; no bus bridge was provided. Amtrak's Pacific Surfliner, which shares the LOSSAN corridor, logged extended delays on both Aug. 13 and into the early hours of Aug. 14, consistent with ongoing disruptions on the affected segment. The suspension lifted after Aug. 14 with no extension.

## Infrastructure Context

Separate from the tidal suspension, OCTA added roughly 1,000 tons of riprap near Cyprus Shore and south San Clemente in recent weeks as precautionary emergency work after hurricane swell moved rock onto the tracks. OCTA indicated it would seek a retroactive emergency Coastal Commission permit covering work since June, with a hearing targeted for the September commission meeting. San Clemente officials have asked the Coastal Commission to allow the city to lead sand replenishment rather than continued rock placement. Community meetings on the Coastal Rail Resiliency Study were held Aug. 10–11, reflecting broader, longer-term concerns about the corridor's vulnerability independent of this tidal event.

## Outlook

The formal NWS advisory has closed, tidal levels are receding, and the Metrolink suspension has lifted on schedule. This astronomical tidal cycle is effectively over. The situation is expected to move to resolved status absent any new advisories or reported impacts.

## Timeline

- **2026-08-07T17:00:00+00:00:** Metrolink announces OC Line suspension south of Laguna Niguel/Mission Viejo for Aug. 10–14, citing forecast high tides.
- **2026-08-09T23:01:41+00:00:** First significant king tide of the cycle: NOAA logs 6.6 ft forecast peak at 19:11 at Newport Beach.
- **2026-08-10T17:00:00+00:00:** Metrolink OC Line suspension takes effect; KTLA reports service halted due to high tides.
- **2026-08-10T20:53:00+00:00:** NWS San Diego issues Coastal Flood Advisory for OC Coastal Areas through 11 PM PDT Aug. 12; cycle peak of 6.9 ft forecast at 20:04.
- **2026-08-12T20:24:00+00:00:** NWS issues updated Coastal Flood Advisory; Aug. 12 evening peak reaches 6.9 ft at 21:38 — tied for cycle high.
- **2026-08-13T06:55:04+00:00:** Amtrak Pacific Surfliner reports extended delays on Aug. 13, consistent with ongoing LOSSAN corridor disruptions.
- **2026-08-13T23:30:39+00:00:** Aug. 13 king tide forecast: 6.5 ft at 22:22 — tidal peak begins declining from cycle high.
- **2026-08-14T04:25:23+00:00:** Amtrak Pacific Surfliner reports extended delays into early hours of Aug. 14.
- **2026-08-14T23:30:43+00:00:** Aug. 14 king tide forecast: 5.9 ft at 23:05 — continued decline from peak levels; Metrolink suspension ends as scheduled.
- **2026-08-15T07:00:00Z:** OC Line suspension ends as scheduled: Metrolink's advisories page lists the closure only for Aug. 10-14 with no extension, weekend service planned as normal; Aug. 15 tide forecast eases to 5.2 ft. Situation resolved.
- **2026-08-15T07:31:32+00:00:** NOAA logs High Tide Alert at Newport Beach; Aug. 15 forecast peak falls to 5.2 ft, marking effective end of king tide cycle.

## Primary sources

1. [High Tide Alert — Newport Beach](https://tidesandcurrents.noaa.gov/stationhome.html?id=9410660) (2026-09-28T19:30:28.489+00:00)
2. [Coastal Flood Advisory — San Diego County Coastal Areas; Orange County Coastal](https://api.weather.gov/alerts/urn:oid:2.49.0.1.840.0.8745e2ada58df6f065ea9e550f9a4176efe8925e.001.1) (2026-08-12T20:24:00+00:00)
3. [Coastal Flood Advisory — San Diego County Coastal Areas; Orange County Coastal](https://api.weather.gov/alerts/urn:oid:2.49.0.1.840.0.1a67094b37b807b9c0d2a9969989c4af1ff2d643.001.1) (2026-08-10T20:53:00+00:00)
4. [KTLA: Metrolink train service in Orange County halted due to high tides](https://ktla.com/news/orange-county/metrolink-train-service-in-orange-county-halted-due-to-high-tides/) (2026-08-10T17:00:00+00:00)
5. [Metrolink: OC Line service suspended Laguna Niguel–Oceanside Aug 10–14 for high tides](https://metrolinktrains.com/news/metrolink-to-suspend-orange-county-line-service-south-of-the-laguna-niguelmission-viejo-station-aug.-10-14-due-to-forecast-high-tides/) (2026-08-07T17:00:00+00:00)
6. [Suspension ended on schedule Aug. 14](https://metrolinktrains.com/train_status/upcoming-advisories/)
7. [San Clemente riprap and Coastal Commission friction](https://www.ocregister.com/2026/08/08/track-repairs-prompt-complaints-over-rip-rap-ahead-of-meetings-on-long-term-solutions-for-trains-beaches/)

## Factoids

- **NWS Coastal Flood Advisory** (regulatory) ([source](https://api.weather.gov/alerts/urn:oid:2.49.0.1.840.0.1a67094b37b807b9c0d2a9969989c4af1ff2d643.001.1)): NWS San Diego issued a Coastal Flood Advisory for Orange County Coastal Areas covering Aug. 10 through 11 PM PDT Aug. 12. Minor flooding of low-lying parking lots, parks, and roads was forecast during evening high tides peaking ~7.2–7.5 ft between 7:30–10 PM. The advisory has since expired; no new advisory has been issued.
- **Metrolink service notice (Aug. 7)** (source_doc) ([source](https://metrolinktrains.com/news/metrolink-to-suspend-orange-county-line-service-south-of-the-laguna-niguelmission-viejo-station-aug.-10-14-due-to-forecast-high-tides/)): Metrolink announced OC Line suspension between Laguna Niguel/Mission Viejo and Oceanside stations for Aug. 10–14, 2026, citing anticipated high tides. Trains originated and terminated at Laguna Niguel/Mission Viejo; no bus bridge was provided.
- **Suspension ended on schedule Aug. 14** (source_doc) ([source](https://metrolinktrains.com/train_status/upcoming-advisories/)): Metrolink's live Upcoming Advisories page (checked Aug. 15) lists the OC Line suspension south of Laguna Niguel/Mission Viejo only for Aug. 10–14, with no extension. No new NWS coastal advisory or tidal damage was reported after Aug. 14; the Aug. 15 forecast peak at Newport Bay fell to 5.2 ft.
- **King tide defined** (definition): King tides are among the highest predicted astronomical high tides of the year, occurring when the sun, moon, and Earth align near perigee/perihelion. In Southern California they commonly produce minor coastal flooding of low parking lots and beach access roads even without storms.
- **San Clemente riprap and Coastal Commission friction** (source_doc) ([source](https://www.ocregister.com/2026/08/08/track-repairs-prompt-complaints-over-rip-rap-ahead-of-meetings-on-long-term-solutions-for-trains-beaches/)): OCTA added roughly 1,000 tons of riprap near Cyprus Shore and south San Clemente as precautionary emergency work after hurricane swell moved rock onto the tracks, and said it would seek a retroactive emergency Coastal Commission permit for work since June at the September commission meeting. San Clemente officials asked the Coastal Commission to let the city lead sand replenishment instead of continued rock placement; community meetings on the Coastal Rail Resiliency Study were held Aug. 10–11.

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