King Tides are the highest predicted astronomical tides of the year, a natural phenomenon displaying the Pacific Ocean’s power along the Oregon coast. Although the term “King Tide” is non-scientific, it is widely used to describe these exceptionally high-water events that occur predictably each year. Along the rugged Oregon shoreline, these tides cause water levels to surge significantly higher than the daily average, briefly transforming the landscape. These powerful, transient events interact uniquely with the geography and coastal infrastructure of the Pacific Northwest.
The Astronomical Forces Behind King Tides
The extraordinary height of King Tides results from a specific, temporary combination of gravitational forces exerted by the sun and the moon. King Tides are generated when the Earth, Moon, and Sun align in a near-straight line, a configuration known as syzygy. This alignment enhances the combined gravitational influence on the oceans, producing what scientists call a perigean spring tide.
The moon’s elliptical orbit also plays a role, as the highest tides occur when the moon is closest to Earth, a point called perigee. When the full or new moon phase coincides with the moon’s perigee, the gravitational pull is maximized. Additionally, the Earth’s orbit brings it closest to the sun, called perihelion, which can further intensify the tidal effect, resulting in the year’s most extreme high tides.
Seasonal Timing and Tracking in Oregon
Along the Oregon coast, King Tides typically occur a few times each year during the late fall and winter months. These seasonal events are predictable because they are governed by the consistent cycles of the sun, moon, and Earth’s orbits. The timing usually falls across three-to-four-day periods in November, December, and January, representing the highest tide sequences for the year.
The Oregon King Tides Project, a collaborative citizen science initiative, helps track and document these events across the state’s coastline. The project encourages the public to photograph the maximum reach of the highest tides to create a visual record of their impact on beaches, estuaries, and infrastructure. This data collection helps state agencies and researchers gather information on coastal flooding vulnerabilities.
Immediate Coastal Impacts and Public Safety
The immediate, short-term effect of King Tides on the Oregon coast is temporary inundation and increased wave action. Flooding occurs in low-lying areas, including estuaries, coastal towns, and occasionally sections of coastal highways like Highway 101. Coastal infrastructure, such as parking lots, roads, and storm drains, can be temporarily overwhelmed by the surging water.
These high tides also exacerbate beach erosion, as the water reaches further inland and carries more energy. The combination of King Tides and winter storms, which often occur simultaneously, can be hazardous, intensifying wave height and leading to significant coastal damage.
Public safety during King Tide events is paramount, as the ocean’s power is magnified. Visitors are advised to check local tide charts and never turn their back on the ocean. The risk of “sneaker waves”—unpredictable, larger waves that surge far beyond the typical wash zone—is heightened, posing a serious threat to anyone near the water’s edge.
Viewing these tides should be done from a safe, elevated distance, such as designated viewpoints or high-ground parking areas. Large logs and debris on the beach can be easily lifted and rolled by the water volume, posing a risk of injury or death. Officials warn that if water is visible over a road, drivers should turn around rather than risk being swept away.
Visualizing Future Sea Level
King Tides provide an important, entirely tangible glimpse into what future “normal” high tides may look like due to long-term sea level rise. While King Tides are a natural, astronomical event, they temporarily simulate the water levels coastal communities will face with greater frequency in the coming decades. This visualization helps planners and residents understand the scale of future challenges.
Observing the current reach of King Tides helps document which coastal areas are most vulnerable to future flooding and erosion. The data and photographs collected by projects like the Oregon King Tides Project are used to validate climate change models and inform local planning decisions. Scientists note that as global sea levels continue to rise, today’s King Tides will eventually become the average daily high tides.
It is important to differentiate the King Tide from a storm surge. A King Tide is a predictable astronomical event, while a storm surge is a weather-driven, temporary rise in water level. However, a King Tide coinciding with a storm or strong winds can compound the effects, resulting in even higher water levels and greater potential for property damage and flooding. This compounding effect highlights the need for communities to prepare for more frequent high-water events.