El Dorado County sheriff's investigators say they hope it wasn't a typical Saturday family outing -- making pipe bombs in front of the wood stove and then testing the explosives by throwing them out the car window during an afternoon jaunt through the American River Canyon.

The result was a series of explosions with no injuries, several frightened witnesses, Dad in jail and Mom under scrutiny for what one deputy described as "unimaginably stupid" conduct.

Justin Lee Brown, 29, was arrested on suspicion of several felonies after allegedly making and detonating the bombs with his girlfriend and their two sons, ages 6 and 8.

Lt. Kevin House, a 24-year sheriff's department veteran, described the incident as "really bizarre and very out of the ordinary."

The level of danger in the car and in the home where the bombs were made was mind-boggling, House said.

A shaken witness alerted El Dorado County sheriff's deputies about 4 p.m. Saturday after trailing a blue Subaru from which they saw at least four pipe bombs emerge as they drove north on Highway 193 toward Chili Bar.

"The explosion was much larger than a firecracker and sent streams of flame and smoke into the sky," according to an El Dorado County Sheriff's report.

The witness told deputies that he thought the occupants of the car were trying to time it so the bombs would detonate as other cars drove over them. Deputies were provided with a license plate number and a description of the car and the male passenger, woman driver and at least one child, who was in a car seat.

With that information, deputies traced the vehicle to Tiffany Dean's home on Bekeart Lane in Coloma. The sheriff's report said Dean initially tried to delay deputies, then yelled at Brown to come out of hiding when they bulled through with guns drawn.

When confronted, the report said, Brown provided detailed information about the caper.

He told deputies he learned how to make the bombs from friends on the coast "and decided to try it so he could show it to his kids."

Brown then described cruising Placerville for breakfast at Denny's with his family before going to various stores to purchase necessary supplies -- including copper pipe and gunpowder. The family then went home and worked on the pipe bombs while sitting in front of the wood-burning stove, the report said.

Those details were cheerfully confirmed by the two boys, House said. During a search, deputies reported finding a 454-gram canister of gunpowder -- with more than 100 grams missing.

Brown was arrested and booked into El Dorado County Jail on several charges, including suspicion of possessing a destructive device, suspicion of possessing an explosive device on a public street or roadway and suspicion of child endangerment, all charged as felonies. His bail is set at approximately $163,000.

Dean was not charged, but officials said they were going to alert Child Protective Services about the incident.