Rogue wave near Ocean Shores not a tsunami, says National Weather Service

GRAYS HARBOR COUNTY, Wash. -- A rogue wave blamed for injuries and damage near Ocean Shores was not a tsunami, the National Weather Service (NWS) said Thursday. Weather experts are instead calling the phenomenon a "sneaker" wave, which is common along the West Coast.

Video documenting the event Saturday shows a wave quickly moving ashore and into coastal estuaries, leading many people to describe it as a "mini-tsunami." But tsunamis are tied to triggers like a strong underwater earthquake or landslide, the meteorologists said. No seismic event of significant strength was observed near the Washington coast or anywhere else across the Pacific Ocean at the time the wave hit.

The NWS concluded the event was likely a sneaker wave, which forms from a buildup of wind-generated wave energy, normally from distant storms. Sneaker waves run significantly further up the shoreline than other waves and may surprise beachgoers. At the time the wave hit Saturday, large wave swells from a distant Pacific storm were reaching Washington's coast, according to the NWS. In that kind of weather event, waves can combine to form larger sets of waves and release their energy on the coastline.

A High Surf Advisory issued by the NWS last weekend warned of waves that could erode beaches and dislodge logs and other debris, causing serious injuries. While this event is considered rare, the NWS said it serves as a reminder that Pacific Northwest beaches can be dangerous places and it's important for people to be aware of the conditions.