Multiple homes in the area of Scenic Way Drive in Ventura could be seen burning from the air. In downtown Ventura, the Hawaiian Village apartment complex was engulfed in flames.
Other homes on High Point Drive above Foothill Road in Ventura were burning as embers blown by whipping winds filled the air.
By the evening hours, the blaze had jumped the 101 Freeway near Solimar Beach, which is located between Santa Barbara and Ventura counties. The freeway remained open.
MORE: Evacuation orders, road closures for Thomas Fire in Ventura County
During the day, a small brush fire burned nearby in an area south of Wildwood Park. The fire was sized up at two acres, but had the potential to grow to 10-20 acres, according to Ventura County fire officials. Homes were possibly threatened.
Vista del Mar Hospital, a behavioral health care facility in Ventura, was razed to the ground by the blaze, ABC7 reporter Sid Garcia confirmed from the scene. All patients and staff were evacuated Monday night.
More than 7,000 homes in Ventura County were under mandatory evacuation as the blaze closed in on downtown Ventura, where multiple structures were reportedly burning. Fire officials said 27,000 people were evacuated from their residences.
The city of Ventura imposed a curfew on residents until the state of emergency is lifted. The curfew, effective 10 p.m. to 5 a.m. prohibits people from being out in public places of the city, including streets and parks. The curfew was established to help protect people as well as limit looting in evacuation areas, officials said.
PHOTOS: Thomas Fire burns in Ventura County
By Tuesday night, evacuations were ordered for La Conchita and areas east of State Route 33 in Ojai and Casitas Springs. Areas west of the highway in Ojai and Casitas Springs were under voluntary evacuation orders.
California Gov. Jerry Brown declared a state of emergency in Ventura County due to the fire.
"This fire is spreading rapidly, but we'll continue to attack it with all we've got," Brown tweeted. "It's critical residents stay ready and evacuate immediately if told to do so."
The fire continued to burn west "out of control," according to fire officials, due to strong east winds that grounded aerial flight crews overnight. One firefighter was injured while battling the blaze.
By Tuesday afternoon, more than 1,100 firefighters were battling the blaze, in addition to fixed-wing aircraft and helicopters helping attack the flames.
Ventura County fire officials said structures throughout the fire area continued to be threatened. Structure protection operations were in place, but fire officials said crews were having trouble accessing some areas due to the intensity of the flames.
Fire officials also warned of worsening conditions amid strengthening winds Tuesday.
In a news conference Tuesday morning, fire officials said the Thomas Fire had "exponential, huge growth" in the overnight hours. Their main areas of concern were Ventura, Santa Paula and upper Ojai, fire officials said.
Initial reports indicated the Thomas Fire started at about 50 acres and moved at a fast rate of speed as winds as strong as 20 mph whipped through the area.
It was reported in the Steckel Park area near State Route 150 and Thomas Aquinas College around 6:30 p.m.. The winds were moving the fire toward the main part of the city, fire officials said.
The blaze eventually jumped SR-150, causing the highway's closure as it continued to eat through dry brush on both sides.
Classes at CSU Channel Islands, including its Thousand Oaks and Goleta campuses, were canceled for Wednesday. Oxnard, Ventura and Moorpark colleges also canceled classes for Wednesday.
The fire also caused power outages in Ventura and Santa Barbara counties Monday night. Officials with SoCal Edison advised that residents should be prepared to be without power for days as crews worked to restore fire-ravaged lines.