Fennessy grew up in Altadena. He recalls talking with his friends and brother - each with homes there. The fire had just sparked in Eaton Canyon.
"I told them, 'You're fine.' That they have nothing to worry about," Fennessy said.
Hours later, the unimaginable happened.
The fire reached their neighborhood. Fennessy was unable to reach his brother.
"His phone stopped working, and so I thought I need to get up there," Fennessy said. "I was fearing the worst."
Then he got a call. Fennessy's brother and family safely evacuated.
"I was already up there and I thought, well I could at least go check on his house," Fennessy said.
Nearly 50 years in the fire service was not enough to prepare Fennessy for what he saw. He described it as "a total nightmare" in a cellphone video showing the damage.
The streets he grew up in were unrecognizable.
"I have not seen anything like this where you drive for miles and miles, and there's massive destruction," Fennessy said.
The fire chief was shocked to find his brother's and neighbor's houses still standing. The surrounding homes were fully engulfed in flames.
With the heavy smoke blocking the sunrise Wednesday morning, and not a fire engine in sight, Fennessy got to work clearing fuels dangerously close to the buildings.
"We tell everybody call 911 and we'll be there. This was a situation (where) you call 911, it's unlikely we were gonna be there," Fennessy said.
The gas meter on the neighbor's house was already melting. After finding a hose, but no water, Fennessy forced entry into the home in search of something to cool down that meter.
"I thought I'll check the refrigerator and all that was in there was some milk and a couple beers," Fennessy said.
This was a first for the fire chief.
"Went back out and kind of ran back there and cooled it off and pulled it back a little bit," Fennessy said. "It wasn't completely out, so I wasn't sure if it was going to rekindle, but it was all I could do."
It was all it took. The two homes are the only ones still standing on that block.
The experience taught Fennessy that firefighting in Southern California is a whole new game.
"I think this is our new reality," he said. "This house-to-house, these urban conflagrations, we're going start seeing them more and more."
Fennessy told Eyewitness News he would've done the same thing had it not been family. He said he did what he could as a trained firefighter and though he's getting a lot of credit, a lot of it was luck in terms of timing and what he was able to find and use.