Just after 10:30 a.m. Sunday, residents near Sack N Save in Nanakuli heard an explosion.
"Boom, boom, boom. So we came over here and checked. That's when we saw the fire," said resident Mabel Priddy.
Priddy jumped into action — warning her neighbors that a wind-whipped wild fire was getting dangerously close to their apartment complex.
"I mean the wind was blowing and the fire was, wow! I thought we would really have to pack up and leave," said Priddy.
It's the second time HFD responded to a fire behind the strip mall off Farrington Highway on Sunday morning.
The first one was quickly extinguished. The second one burned close to five acres.
Both blazes appeared to have started in a nearby homeless camp. It's estimated upwards of 50 people were living mostly hidden among the keawe trees.
"We saw a lot of them run out with their dogs and stuffs," said Tammy Kane.
Kane was doing laundry at the laundromat. She says the fire burned all the way to the fence behind the business.
"We saw the smoke and then next thing you know it was red flames," said Kane. "We left everything. We just camp back now. Hopefully our clothes was still here."
While dozens of firefighters doused the scorched brush with water, HNN spoke with a camper who said he was cooking when his fire got away from him. HNN asked officials about that man's claim and were told the cause remains under investigation.