Firefighters say they could see the smoke from the building more than a mile away.
Investigators are trying to figure out what caused a large, abandoned house to catch fire Monday in Lakeside.
A San Diego County Sheriff’s Department helicopter spotted the fire on Lemon Crest Drive around 1 a.m. Smoke could be seen more than a mile away.
"The whole hill was on fire. The flames were as high as the trees, at least 30 feet," neighbor Bret Shaffer said.
Firefighters said the fire was challenging because of the size of the home and the amount of debris spread through the house.
Because the flames were so intense, crews said they had to launch a defensive attack when they arrived.
“It’s an old, wooden building so there’s a very heavy fire load in it. We put a lot of water on it. It just takes a long time when the whole structure is completely involved to get it extinguished,” said Captain Bernie Molloy of the Lakeside Fire Department.
Public records show the home was sold last November. Neighbors told NBC 7 they believe an investor bought it and no one has lived in the home for months.
No other homes were threatened. The home was located on a large lot just southwest of Lemon Crest Elementary School.