The last in the three-month series of king tides returns to the Oregon coast this weekend.
In Oregon, king tides occur three months in the winter and three times during the summer when the Earth, moon and sun align to produce the highest tides of the year – ranging from 9 to 12 feet on the central Oregon coast. These tides are 2-3 feet higher than tides during the quieter summer months.
The first king tides sequence occurred over Thanksgiving, then returned during Christmas. From Friday through Sunday high tides reach 11.5 feet and low tides drop to around 5 feet. High tides occur between 10 a.m. and 12:30 p.m. those days.
The king tides have also become a popular tourist attraction, drawing visitors to high areas along the coast to watch the crashing waves.
The series of high tides also coincides with the Oregon King Tides Project, a citizen-science effort, organized by CoastWatch and the Oregon Coastal Management Program. The project creates a time-lapse glimpse of how rising sea levels are affecting coastlines around the world.
The use of king tides to create “a time-lapse glimpse of how rising sea levels are affecting coastlines around the world” has dubious and misleading value. Any given set of king tides can be significantly higher or lower depending on several factors unrelated to rising sea level:
1. rainfall
2. wind direction and duration
3. atmospheric pressure
With sea level rising at different rates on different coastlines and even falling on many coastlines, trying to use very variable king tides to measure accurately sea level that rises maybe 1/8th of an inch a year is folly.
Sea level rise is real and on some coasts it is a near term threat. On other coasts the threat is distant and Oregon has some areas of rising coastline where sea level threat actually diminishes.