Dateline | June 28, 2013
>> reporter: the road is a width, a snake as the it wind away from the california coast, up through the golden hills past the celebrated vine yard and north into the central valley . highway 101 . who among us knows where fate lies waiting? or why beneath the bridge south of a town called buhlton, the concrete is stained a permanent black.
>> people have a sense that it could have been them.
>> reporter: yes, it certainly could have been. but this time -- this time the fate that came barreling out of nowhere was for a young mother and her two little girls. but by the time it ended, a whole bridge full of fates was changed. by the awful amaze thing that happened here.
>> you have two that can't breathe and two kids -- [ indissternable ]
>> reporter: january 12 , 2012 , kelly groves was taking her two little girls on a weekend trip. her newborn milo and 4th grader sage. sage the soccer star. sage the dancer.
>> she borrowed her sister cary's bmw, felt safer, more reliable.
>> reporter: she strapped the baby seat in the back.
>> reporter: took the two girls.
>> she did. i think -- sage had asked to sit in the front. and -- kelli thought about it. she said "no you sit in the back."
>> kelli 's husband jason and boy wilder had their own plans this weekend. a girl's get away. a trip to see the mission church four hours north of their home in orange county .
>> so kelli was planning a nice trip for sage and milo to see the mission to go to the farmer's market. it sounded like such a great trip. i know she was so excited.
>> reporter: sure. by midday, kelli pulled out of a rest stop in santa barbara heading up the 101. baby milo napped as big sistcyst sage watched a movie. a series of events. she huddled under the blanket to cut the wind noise from a win dethat wouldn't close. behind kelli , truck driver , brian gomez watched the road ahead of him and thought about the big night he had planned. he had no idea.
>> i was going to a concert at the casino in buhlton that evening.
>> reporter: traffic flowed around him. the impatient drivers weaving in and out. laughing families gliding along. the lumbering big rigs that carry the lifeblood of california south and north and south again. he could see kelli 's car ahead. and to her right. a big 18-wheeler.
>> i was traveling a couple hundred feet behind a bmw in the fast lane and semitruck in the slow lane.
>> reporter: driving the semi, charles allison jr. he dropped scrap metal . he had been driving around. he was headed home, 50 miles up the road. so there they were, the big rig driver, the young mother and her girls in the bmw, and the tow truck driver. eager to finish work. all closing in on the bridge south of buhlton. a few miles away at county firehouse, paramedic greg knuckles was enjoying a quiet afternoon. couldn't see the future of course, the trauma to come on the bridge down the road.
>> we had done our training. we were just going to have an average day at the firehouse, you know?
>> reporter: then it was 2:30. and life as any of them knew it ended. right in front of tow truck man, brian gomez, who remembers a little car on the left. and a semion the right.
>> all of a sudden, the semitruck swerved towards the bmw and hit the bmw.
>> the semismacked once into the bmw, then again, going over it, dragged it along, 30, 50 feet or so.
>> then started slamming through the bridge .
>> all that momentum, the 18-wheeler went right off the bridge and into the gap between the spans.
>> just looked like a snake going into the hole.
>> reporter: the truck exploded in the creek bed. like a blast from a giant missile. but the car, kelly's car, gomez saw the car had been caught on the bridge somehow. stayed there, a crumpled mass, teetering over the inferno below.
>> wedged on the bridge . a mangle of metal. bent on to the bridge .
>> reporter: brian gomez was assaulted by a wall of heat as he stumbled from his truck and called chp. chp sergeant, don clockworthy rushed out of his office a couple miles away .
>> i looked in this direction and what i saw was what i would describe, looked like a bomb had dropped.
>> reporter: it was much later when sergeant clockworthy took us to the bridge . showed us where the truck plunged into the ravine and where by some improbable trick of physics, kelli 's car did not. not quite.
>> we arrive on scene. there is no bridge railing here. none t so it is just straight down. drop. you have got a car crushed that's teetering.
>> reporter: as if the next gust of wind may send the obscenely twisted dangle of metal and flesh off the edge into the inferno below. charles allison jr., the big rig driver was no more. and one look told brian gomez the bmws passengers were dead as well. he walked over to the ungodly mess that remand of the car as the it teetered at the precipice.
>> my mind was thinking there is nobody could be alive in that car. that little bmw, it was so smashed up. you couldn't tell what kind of car it was by then.
>> reporter: that's when he heard the sound he will never, ever, forget. someone was screaming. i was look my god, some one is alive in this car somehow. i couldn't see her at first. so i got back on the phone. i called highway patrol . i said i just called you with this major accident. soc someone is alive in the car. get here quick.
>> reporter: some one was alive. probably not for long. and from the looks of the car, that someone could fall.