Thumbnail photo: The tsunami that struck Crescent City on July 30, 2025 caused complete separation of the harbor’s H Dock. | Photo courtesy of Mike Rademaker
Five months after an earthquake near Kamchatka sent a tsunami into Crescent City, the harbor has received the state disaster declaration needed to begin making repairs, Harbormaster Mike Rademaker said.
California Gov. Gavin Newsom issued a statement Dec. 23 declaring a state of emergency in Del Norte County due to the tsunami that struck early the morning of July 30. The California Office of Emergency Services on Monday confirmed that the Crescent City Harbor District’s request for disaster assistance funding was approved, Rademaker told Redwood Voice Community News via email Tuesday.
The next phase, according to Rademaker, is for the Harbor District and Del Norte County to coordinate with state emergency officials to figure out a project list as well as scope and cost estimates so the Harbor District can be reimbursed. He said he hopes “things will happen within the next couple of weeks.”
The Harbor District will also pursue projects that will protect its infrastructure against future disasters, the harbormaster said. He added that the damage in July was significantly less than the harm the Tohoku earthquake and tsunami caused Crescent City in March 2011.
“Even with the Harbor District’s current preliminary estimate in the roughly $2 million-$5 million range (which may still evolve as underwater components and embedded utilities are fully evaluated), that level of impact is a substantial improvement compared with the approximately $50 million in damage to the Crescent City Harbor from the March 2011 tsunami,” Rademaker said. “The difference reflects mitigation and resilience investments made after 2011.”
Spawned by a magnitude 8.8 earthquake that struck off the east coast of Russia’s Kamchatka Peninsula at about 4:25 p.m. local time July 29, the tsunami prompted evacuation warnings in the areas of Del Norte County closest to the water.
Del Norte County set up a temporary evacuation site at the Veteran’s Memorial Hall and people with RVs were permitted to park at the Walmart, Home Depot and Del Norte High School parking lots.
Tsunami surges began funneling into the harbor at about 12:50 a.m. July 30. Surges reached a maximum height of about 4 feet, according to National Weather Service Warning Coordination meteorologist Ryan Aylward.
At the time, Rademaker said initial damages were estimated at $1 million with H Dock in its marina bearing the brunt.
At a special Harbor District Board meeting on Aug. 7, Moffatt & Nichol vice president and coastal engineer Rob Sloop discussed the need to conduct bathymetric surveys and sonar scanning to determine how much sediment the tsunami deposited into the federal channel as well as how it changed the ocean floor.
At that meeting, Sloop noted that an underwater inspection was necessary to repair H Dock and urged commissioners to think about making the port resistant to future tsunamis.
University of Southern California coastal engineering professor Patrick J. Lynett also conducted an analysis of the damage based on video footage and data modeling. According to a press release Rademaker issued before the Aug. 7 meeting, Lynett stated that the tsunami currents accelerated beneath H Dock creating a drop in pressure strong enough to overcome the dock’s buoyancy.
On Wednesday, Rademaker said that U.S. Army Corps of Engineers surveys conducted before and after the tsunami determined that it deposited about 40,000 cubic yards of sediment into the port’s entrance channel. It also caused shoaling among the Harbor District’s docks, which, Rademaker said, can be a navigational hazard to vessels.
“That’s what needs to be addressed most urgently and then the rest of it is just the overall depth being reduced, which impacts the size of vessels that can moor at the harbor,” he said. “Because we’re considered a shallow harbor with an average depth of about 15-20 feet, any additional sediment has a significant impact.”
According to Rademaker, the change in the Harbor District’s underwater elevation may be a long-term challenge it will have to address since the safety margin for large vessels is reduced.
Another long term challenge for the Harbor District is reducing “repeat damage risk” from future tsunamis. According to Rademaker, H Dock was designed and built to absorb incoming energy from tsunamis before it penetrated further into the marina.
The Harbor District may be able to enhance that concept. Some engineer proposals suggest that adding more wave attenuation structures would further absorb tsunami energy, Rademaker said. There was also discussion about changing the shape of the dock’s floats under the waterline in an effort to change the buoyancy, he said.
“One of the problems was the speed with which H Dock was raised from the tsunami current,” he said. “It was like that sudden jolt is what caused the floats to raise at different times, which caused the electric cables to get severed.”
Rademaker suggested that changing the dock’s design in a way that it would raise more gradually in the face of strong currents would be an improvement.
A further potential guard against future tsunami damage may be to change the mouth of the harbor itself. At the Harbor Board’s Aug. 7 meeting, Sloop suggested widening the entrance to the inner boat basin would make the surges less intense.
However on Wednesday, Rademaker noted that the current structure protects against storm damage.
“We have to find the right balance to maximize storm protection — the average storms compared to catastrophic events,” he said.
