Sneaker waves are, per the National Weather Service, "potentially deadly waves that surge further up the beach than expected, overtaking the unaware" — arriving after 10 to 20 minutes of small surf and running at least 150 feet up dry beach. They matter to tidepoolers because minus tides happen in the quietest hours: 115 of the West Coast's 414 daylight minus tides in 2026 bottom out between 5 and 8 AM, La Push (NOAA 9442396) included.
What is a sneaker wave?
The name is the mechanism. A sneaker wave is not a rogue wave out at sea or a tsunami; it is a single surge, on an otherwise ordinary day, that runs much farther up the beach than anything in the preceding minutes suggested was possible. The National Weather Service's sneaker-wave safety page states the trap plainly: "There can be 10 to 20 minutes of small waves right before a sneaker wave strikes." Twenty minutes is longer than most people watch the ocean before deciding it is calm. Then the one wave arrives, and it "can run up the beach by at least 150 feet (45 meters) into the dry beach."
Two details in the NWS guidance explain why the Pacific Northwest takes these waves so seriously. First, the logs: Northwest beaches are floored with drift logs, and "sneaker waves can run up on the beach, lifting or rolling these extremely heavy water soaked logs." A log that outweighs a car, briefly buoyant, is the most dangerous object on the beach. Second, the water itself: sneaker waves "can happen on any surf coast; however, in the Northwest, water temperatures are frigid," and "exposure to the cold water can cause cold water paralysis in the limbs within minutes, further impairing the individual's ability to escape the wave."
What causes them? Storms you can't see
For a long time the honest answer was "we don't fully know." A 2023 study — Observations of extreme wave runup events on the US Pacific Northwest coast, published in Natural Hazards and Earth System Sciences by Oregon State University researchers with a Pacific Northwest National Laboratory scientist and National Weather Service forecasters in Portland — filled in a large piece. The mechanism involves two kinds of waves. The swell you can see breaking is made of surface gravity waves. Underneath them travel infragravity waves: much longer, lower waves fed by the energy of the visible swell. When a large storm is running far away — near Alaska, or in the South Pacific — the swell that arrives here is long-period, with unusually generous spacing between waves, and that spacing pumps energy into the infragravity band. The result is a surge that periodically runs far beyond where the ordinary breakers have been reaching.
The study's centerpiece is January 16, 2016, a day that produced extreme run-up along roughly 1,000 kilometers of coast — Washington, Oregon, and northern California at once. At the onset of the event, peak wave periods lengthened from about 12 to about 25 seconds, and the worst-hit locations recorded inland excursions of hundreds of meters. Not every coast can produce this: per the university's summary of the work, the Pacific Northwest's narrow continental shelf and its exposure to far-offshore winter storms are what make it vulnerable.
The research also yields the one field observation a beach visitor can actually use, and it is a counting exercise: "Count the seconds between each wave breaking on the shore. The more time between waves, the more likely a sneaker wave could occur. If the waves are 20 or more seconds apart and look well-organized, with long, clean lines of swell waves, be especially cautious." Long, clean, widely spaced lines of swell look beautiful and calm. That is precisely the look to distrust. As study co-author Tuba Özkan-Haller put it: "One sneaker wave can change the course of life."
Why dawn windows are exactly when to remember this
The tide calendar and the sneaker-wave problem intersect at an awkward hour. On the Pacific coast, summer's lowest tides land at dawn, and the 2026 histogram makes the point numerically: of the 414 daylight minus tides across our 11 West Coast stations this year, 115 bottom out in the 5, 6, and 7 AM hours, and another 132 in the 4, 5, and 6 PM hours. The best tidepooling of the year happens at first light and last light — thin crowds, long shadows, and, on the open coast, nobody else watching the water.
That is the argument for building the watching into the schedule. Every window on our station pages carries an arrive-by time one hour before the low. The NWS instruction — "Watch the ocean for at least 20 minutes. Study its wave patterns." — fits inside that hour with room to spare: arrive on time, and the wave-watching is done from the top of the beach before you commit to the rocks at the bottom of it.
Here is the next morning this matters concretely. The outer coast's deepest remaining run of 2026 peaks on Wednesday, August 12, when all five of our open-ocean stations bottom out between 6:19 and 7:04 AM:
| Station | NOAA id | Low (ft MLLW) | Low time | Arrive by | Score |
|---|---|---|---|---|---|
| La Push | 9442396 | −2.31 | 6:58 AM | 5:58 AM | 90 (Exceptional) |
| Garibaldi | 9437540 | −1.77 | 7:04 AM | 6:04 AM | 85 (Great) |
| Newport | 9435380 | −1.91 | 6:46 AM | 5:46 AM | 88 (Great) |
| Charleston | 9432780 | −1.72 | 6:35 AM | 5:35 AM | 81 (Great) |
| Port Orford | 9431647 | −1.74 | 6:19 AM | 5:19 AM | 80 (Great) |
Computed 2026-07-26 from NOAA predictions; windows and scores per our methodology.
Note what the clock is doing: La Push's window that morning opens at 4:30 AM, but only 195 of its 295 minutes are in daylight — the front of the window is dark. A dawn arrival on an empty beach, eyes still adjusting, is the exact opposite of the NWS's twenty attentive minutes unless you plan those minutes deliberately. The Puget Sound run of August 8–13 and the Oregon hub cover where to take these mornings; this page is about the part of the morning that happens before you look down at the pools.
What the officials ask of you
Safety guidance on this site is quoted, not invented, so here is the standing advice from the three agencies whose beaches these are.
The National Weather Service, from its sneaker-wave page: "Watch the ocean for at least 20 minutes. Study its wave patterns." And the two rules that never come off the list: "Never turn your back on the ocean," and "Stay off and well clear of large logs and debris fields that are anywhere near the surfline or below the high water marks."
Oregon State Parks, from its beach safety page: "Always keep one eye on the ocean so you won't be caught off guard if a bigger wave surges up the beach." On the logs, the physics behind the rule: "Stay away from logs on the beach or in the surf. The logs absorb water like sponges, increasing their weight by up to several tons." And on the tide itself: "Know when the tide is coming in, especially when exploring tidepools or secluded beaches. Incoming tides can quickly leave you stranded away from shore."
Olympic National Park, whose coast includes La Push's beaches, folds both hazards into one line of its tidepooling guidance: "Watch closely for the returning tide and 'sneaker waves.'" And its general coastal rule: "Wherever you go along the coast, always carry a tide table and know how to use it!"
Before a dawn window, check the NWS forecast for your stretch of coast at weather.gov — coastal offices flag elevated sneaker-wave conditions in their beach-hazard messaging when the swell calls for it. Then let the Tide Window Finder handle the tide half of the plan: the low, the window, and an arrive-by time with twenty minutes of ocean-watching already built in.