King tides in 2010 increased the water level around Indian Island. King tides are expected Sunday and Monday and high surf is likely Thursday. (Times-Standard file)
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The National Weather Service has forecast surf stemming from a storm offshore will reach between 30 to 35 feet Thursday and king tides will coincide over the weekend with a full lunar eclipse.

The high surf will affect local beaches, jetties and docks. Residents and visitors alike are encouraged to stay away from the waterfront as a result.

“Right now we’re expecting the surf at just before sunrise to not be very large but it will go from 10 to 12 feet to up to 35-foot breakers and it will ramp us fast right around sunrise,” said NWS meteorologist Ryan Aylward. “We really encourage people to not be fooled by an ocean that doesn’t look too bad and then get caught by heavy surf. There’s a storm just off the coast generating swells. Every year, we get one or two storms that generate waves like this, so this is very typical.”

High surf during the winter months is not uncommon in Humboldt County and the heavy surf is expected along local beaches throughout Thursday before slowly diminishing. By the weekend, the high surf will have subsided but the king tides will then roll in and that will lead to localized flooding.

“The high tides could cause minor coastal flooding along the bay,” Aylward said, adding the wind and rain will most likely remain through the weekend as well. “King Salmon often floods with the high tides and there are areas and roads in the Arcata Bottoms that will flood as well. The winds will be similar and the rain may get a little heavier but nothing too crazy for winter. We haven’t seen any flooding on local rivers and the rain should turn to showers by Thursday evening.”

Sunday night will bring what is called a super blood wolf moon, the last lunar eclipse of the decade, according to Accuweather. Sunday evening’s full moon — which will likely be hard to spot from the North Coast — will see the moon change to a red shade during the height of the eclipse. It is also taking place during the year’s first super moon, when the moon appears larger than normal.

The king tides will occur Sunday and Monday and Arcata is urging local residents to take pictures of areas around the bay as the king tides move in an effort to document the water level at high tide.

The city has marked 15 locations in Arcata and the marsh extending to the Bay Trail South of specific interest and you can locate those sites by checking the city’s website at http://www.cityofarcata.org/759/Sea-Level-Rise.

The king tides will be the highest tides of the year and the tide is expected to reach 8 feet 6.5 inches by 11 a.m. Sunday and 8 feet 7.3 inches Monday. The measurements will be used by the city to help plan for rising ocean levels that will impact future development.

“The initiative is to get people thinking about what the high tide will look like in the coming years as the ocean rises,” said Jennifer Kalt, director of Humboldt Baykeeper. “Humboldt Bay is experiencing twice the rate of sea level rise as the rest of the state and Jay Patton and his fellow geologists at Cascadia GeoSciences have found that the ground beneath the Humboldt Bay area is sinking due to tectonic subsidence at the same rate that sea level is rising — meaning that this area has twice the rate of relative sea level rise as the state average. Conversely, the coast in the Crescent City area is uplifting due to tectonic activity at the same rate as sea level rise — meaning that there, the rate of relative sea level is essentially zero.”

Kalt said the goal is to document the high tides so that future planning can be geared toward the rise of ocean levels and for low-lying areas in Arcata and the county that will mean impacts to wastewater treatment plants and where to build future public infrastructure.

“We need to raise people’s awareness and we need to plan for this because it’s going to happen,” Kalt said. “It will only be disastrous if we fail to plan. We built all these dikes 100 years ago and now the bay is 18 inches higher and if we’re going to spend public money to upgrade wastewater treatment we should start thinking about moving them. Both Eureka and Arcata are looking at $40-to-$50 million upgrades, but where are they going to move to?”

Arcata has made available maps that can be downloaded to a cell phone as well as a desktop computer and for more information check the king tide community action observation map at http://www.cityofarcata.org/DocumentCenter/View/6799/King-Tide-Guide-01-2019.

Dan Squier can be reached at 707-441-0528.

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