The sculptures in Webster's Woods, a 5-acre outdoor art park, were broken or pulled from their stands, said Director Robin Anderson.
The attack happened late Wednesday or early Thursday.
Port Angeles police officers Thursday afternoon had no leads or descriptions of vehicles, and the police department is seeking information leading to the vandal or vandals.
The first sign of the destruction was an overturned 8-foot-tall mushroom sculpture that Anderson spotted at about 10 a.m. Thursday when she arrived at her office at the arts center at 1203 E. Lauridsen Blvd.
"It's right outside my window," Anderson said.
At first, she thought the giant wooden mushroom had fallen because of natural erosion or aging, she said, but an hour later, a visitor to the art park came in to report more damage.
Webster's Woods features artworks by people from over the Pacific Northwest and Canada, including artists on the North Olympic Peninsula, and draws visitors from around the world.
A mosaic concrete angel, "Paul Bunyan's Chair" and other large, heavy works were pulled from their anchors or knocked over, and some were damaged beyond repair, she said.
"The 'Dancing Sweaters' were pretty damaged," she added.
Some sculptures were so heavy, Anderson suspected more than one person pulled them out of the ground or knocked them over.
The center was still assessing the damage Thursday afternoon and didn't yet have an estimate of the value of the damage.
Anderson said the final number could top $10,000.
The arts center and the park will be closed during the investigation and cleanup, Anderson said.
There are more than 100 pieces of sculpture and other art in the garden, with about a third of them damaged to some degree, she said.
Many of the pieces are older and weathered, so the monetary value is difficult to estimate.
But Anderson said the damage to the heart of the art community is the worst part.
"It's unmeasurable," she said.
Police are seeking information leading to the vandals, Officer John Nutter said Thursday.
Anyone with information can phone Port Angeles police at 360-452-4545 or at North Olympic Crime Stoppers at 800-222-8477, with case number 2012-22470.
A reward of up to $1,000 is offered from Crime Stoppers for information that leads to an arrest in the case.
Peninsula Daily News is a media partner of KOMO News.