The sky rumbled over Puget Sound on Saturday night, startling a whole region of people from Bainbridge Island to Seattle and beyond.
It couldn't be thunder. The skies were clear. Could it really be fireworks? In September?
Many took their questions and their grievances to social media.
"It's louder than the 4th of July at the Space Needle," posted one user on X, formerly known as Twitter, on Saturday night.
According to a Facebook post from the Bainbridge Island Fire Department, someone was holding a private fireworks show on the water to the south, beyond the island's jurisdiction, starting around 9:30 p.m.
Some were lucky enough to see the surprise display. One person posted a video on X showing firework after firework after firework lighting up the night sky, for minutes on end.
The show was legal, too, agencies confirmed.
The U.S. Coast Guard confirmed Sunday morning it had received an application for a marine event permit from Western Display Fireworks, a company in Canby, Ore. Western Display Fireworks did not immediately respond to a request for comment Sunday morning.
On LinkedIn, Western Display describes itself as "a fourth generation family owned business offering the finest in pyrotechnic productions." It claims to be the oldest and biggest aerial display company in the Northwest, with more than 60 years of experience.
Last year around the same time, Western Display put on another fireworks show off Bainbridge Island, KUOW reported. And The Kitsap Sun wrote about a similar display 25 years ago.
So far, the hosts of the private displays have remained shrouded in mystery. For the show in 1998, a representative of Western Display told the Sun that the sponsors prefer to remain anonymous, and that they were just "people who like fireworks."
The Bainbridge Island Fire Department said the commercial operator holds a general display fireworks license and a pyrotechnic operator license issued by the Fire Protection Bureau of the Washington State Patrol.
They said the operator also got a permit from the Seattle Fire Department to load the fireworks and got approval from the Coast Guard for the marine event. Beyond that, no additional permits were needed.
U.S. Coast Guard Petty Officer Annika Hirschler said while the company applied for a marine events permit, the Coast Guard did not issue one. They told Western Display Fireworks it was not necessary because "the event does not introduce any extra or unusual hazards that would jeopardize the safety of human life on the navigable waters for the U.S."
The Bainbridge Island Fire Department didn't undertake any special preparations but was prepared to respond if the Coast Guard requested help, Chief Jared Moravec said. The department didn't receive any dispatched calls related to the fireworks display, he said.
In a Facebook post, the Bainbridge Island Fire Department urged people not to complain to emergency services.
"Please do not call 911 with any complaints," the department said on Facebook. "Let's keep those lines open for emergency reporting."
That didn't stop people from complaining online, though.
"World War 3? Apocalypse? No just a bunch of idiots setting off professional fireworks on Bainbridge Island," posted another user on X, along with a screenshot of the Facebook post from the Bainbridge Island Fire Department.