Firefighters in California made significant progress on Sunday in containing a wind-driven wildfire that burned thousands of acres near Tracy, about 60 miles east of San Francisco.

The fire, known as the Corral Fire, started on Saturday afternoon in the grassy hills near the Lawrence Livermore National Laboratory.

While the cause of the fire is still under investigation, it had burned approximately 22 square miles by Sunday afternoon.

Despite threatening the area, including parts of Tracy with a population of 100,000, the research center itself was not immediately endangered.

Evacuation orders were issued on Saturday for thousands of residents but were lifted on Sunday evening as conditions improved, NBC News reported.

One home was destroyed in the blaze, and two firefighters sustained minor to moderate burns on Saturday.

With calmer winds and milder weather on Sunday, firefighters expressed optimism about containing the fire further.

Written by B.C. Begley