Firefighters battle to maintain the upper hand on a huge fire north of Los Angeles

NEW: Red flag warnings extended through 10 a.m. Friday in LA and Ventura counties.

NEW: By Wednesday night , about 14% of the Hughes Fire had been contained.

More than 31,000 people have been ordered to evacuate from the fire, and another 23,000 are under evacuation warnings.

The Hughes Fire broke out late Wednesday morning and in less than a day had charred nearly 16 square miles ( 41 square kilometers ) of trees and brush.

The federal Bureau of Alcohol, Tobacco and Firearms is investigating the causes of the fires but has not released any findings. Several lawsuits have been filed by people who lost their homes in the Eaton Fire , alleging Southern California Edison's equipment sparked the blaze. On Tuesday , a judge overseeing one of the lawsuits ordered the utility to produce data from circuits in the area where the fire started. ___ Weber reported from Los Angeles . Associated Press journalists Ethan Swope in Castaic , Hallie Golden in Seattle , Jaimie Ding in Los Angeles and Julie Walker in New York contributed to this report..