The Thomas Fire, which started in Ventura County a week ago and crossed into Santa Barbara County over the weekend, has burned more than 230,000 acres, making it the fifth largest blaze in modern California history.

On Sunday, the Thomas Fire, covered much of San Luis Obispo County with smoke. At certain points, the sky turned orange up and down most of coastal SLO County.

As of Monday morning, the Thomas Fire has burned 230,500 acres and is 15 percent contained, according to Cal Fire. The blaze has destroyed 794 structures and damaged 187. Another 18,000 structures are threatened.

The Thomas Fire ignited on Dec. 4 north of Santa Paula near highways 150 and 126. Santa Ana conditions have fueled the blaze, pushing it into Santa Barbara County and resulting in significant fire activity in the Carpinteria area.

Gusty northeast winds are expected to drive the blaze into the city of Santa Barbara. The fire is also continuing to threaten Summerland, Montecito and other neighboring areas, in addition to Carpinteria.

Mandatory evacuations remain in effect for numerous parts of Ventura County, including the city of Ventura. Likewise, parts of Carpinteria, Montecito and rural Santa Barbara County are under mandatory evacuation orders.

Authorities are carrying out voluntary evacuations in other parts of Carpinteria and Montecito, as well as portions of the city of Santa Barbara. School closures are in effect Monday as far north as Santa Maria.