An eastbound hunk of an apparent meteor barreled over the Central Sierra foothills on Sunday morning, rattling windows and nerves from Groveland and Placerville, to Modesto and Reno.
A loud bang was heard about 8 a.m. Some people also reported seeing a bright flash.
The incident, reportedly the result of an annual meteor shower, was immediately followed by a cascade of phone calls to fire and law enforcement agencies throughout Central California and western Nevada.
The Tuolumne County Sheriff's Office received at least 50 calls Sunday morning from shaken residents, said Sgt. Jeff Wilson.
A national warning system, called NAWAS, a phone-tree connecting law enforcement and other public-safety agencies across the country, had earlier put out a notice regarding the possibility of meteor sightings Saturday and Sunday, the result of the Lyrid meteor shower, according to a Wilson and Sheriff's Office dispatcher in Tuolumne County.
Stefanie Henry, meteorologist at the National Weather Service in Sacramento, said several meteor sightings were reported overnight to the state's version of NAWAS, called CAWAS.
Most were from Southern California, including a big one in Orange County, she said, adding similar meteor sightings were reported as far away as the Eastern European republic of Hungary.
The Lyrid meteor shower is an annual event, and this year's was particularly vivid, Henry said.
In the western U.S., the shower peaked about 5 p.m. Saturday, she said.
The meteors are floating space debris left by comet Thatcher, which last passed earth in July 1861.
As comets, like Thatcher, pass the Earth in their routes around the sun, they shed ice, dust and pieces of rock.
When the Earth makes its annual, 67,000 mph jog around the sun, it collides with the space junk.
These meteors typically vaporize when they crash through the Earth's atmosphere at supersonic speeds — resulting in a bright flash and, in some instances, a sonic boom like that of a jet fighter.
The Lyrid showers appear in a part of the sky near what we view as the constellation Lyra — hence the name.
As of late Sunday morning, Henry said, it didn't appear anything reached the ground.
Cal Fire communications officer Maryjo Boon, in Calaveras County, said there was no confirmation that anything hit in the Central Sierra, though many people thought something must have.
Reports of fires in the Big Hill area of Tuolumne County around the same time raised eyebrows, but were confirmed to be property owners' private burn piles.
"We received reports of people's windows rattling and doors coming open," she said, adding that calls came from Mountain Ranch, Groveland, Tuttletown and Phoenix Lake.
Sunday afternoon, Capt. Ruth Castro, with the North American Aerospace Defense Command, NORAD, in Colorado Springs, Colo., said federal scientists were investigating reports some debris may have struck near Stateline, Nevada, in an area known as the Kingsbury Grade.
The Douglas County Sheriff's Department in western Nevada had not received such reports.
Castro had little other information, as NORAD tracks man-made objects, like planes and missiles, not meteors.
One witness of Sunday's meteor flyby in Arnold told The Democrat that trees were briefly swept from west to east.
Another said she was knocked off her feet.
"I was walking down the stairs in the garage when the whatever happened," said Arnold's Erin Girard-Hudson.
"It knocked me off my feet and was shaking the house," she said, adding her daughter, Elsie, 2, was crying. "It sounded like it was next door."
Taunya Day Struhs, of Pine Grove, Amador County, was rattled as well.
"Our windows vibrated, we were stymied as to what it was. So bizarre," she said by email.
Jasmin Yager, of Salida, who just turned 6, offered a colorful description of the meteor's bright flash, which she saw while outside playing.
"She said she saw a big beautiful bird. It was a red one with lots of rainbows," said mother, Monica Yager.
"My husband and I were literally having coffee and donuts. ... We were like, 'Oh, OK honey.' "
Scott Bright, of Placeville, said the sound seemed to come from the west, the rumble only mildly approximating the thunderstorms he became accustomed to while living in Florida.
"It started to rumble then it built incredible energy… like direct-hit thunder bolt, then staged-rocket sounds across the sky. In 53 seconds, it was gone," he said.
"It was the loudest thing I ever heard. It screamed across the sky… thousands of miles per hour," he said, adding he called friends in New York to check if they'd seen it. They hadn't.
"We're lucky it didn't hit. ... When that happens, you better call the friends you love. I thought we were gone."
Union Democrat Calaveras County reporter Sean Janssen contributed to this story.