A fast-growing brush fire ignited on Monday morning in southern California, prompting evacuation orders and damaging at least one home.

The Sandy fire was reported just after 10am in Simi Valley, a city in Ventura county about 30 miles north-west of Los Angeles.

The blaze had spread to over 700 acres shortly before 2pm. The fire had no containment as of Monday afternoon.

Mandatory evacuation orders were issued for more than 20,000 residents in the southern part of the city, the New York Times estimated. The city has a population of more than 125,000 people.

Aerial footage from local TV stations showed at least one home on fire. Fire officials did not provide an exact count. Multiple helicopters could be seen performing water drops over the blaze, while mass clouds of gray smoke blanketed the neighborhood.

Crews were scrambling to keep flames from moving down slopes into the suburban neighborhoods of Thousand Oaks.

A National Weather Service advisory warning of winds 20 to 30mph was issued for the area until 3pm.

“We are still anticipating a change in the weather to our advantage,” said Ventura County Fire’s Andy Van Sciver said, according to ABC 7 News.

The Associated Press contributed reporting