A fast-moving wildfire exploded to roughly 10,200 acres near the Los Angeles County community of Castaic Wednesday morning, prompting mandatory evacuation orders and road closures, authorities said.

Firefighters are responding to a brush fire in the Castaic area of Los Angeles County Wednesday morning, according to the Angeles National Forest.

The Hughes Fire broke out late Wednesday morning and in less than a day had charred nearly 16 square miles of trees and brush near Lake Castaic.

The investigation is critical for not only understanding what happened, but for ensuring it never happens again, said an attorney for 300 Altadena residents.

All 17 people who died in the wind-fueled Eaton Fire in Lost Angeles were in an area where the first evacuation order wasn’t sent until more than nine hours after the fire started.