By Alex Dobuzinskis

LOS ANGELES (Reuters) – Hundreds of people have evacuated to escape a wildfire in coastal Southern California and a larger blaze in rural New Mexico as hot weather feeds the flames, raising health concerns in other regions, officials said on Thursday.

Santa Barbara Sheriff Bill Brown told a news conference his deputies had asked occupants of 400 homes and businesses to evacuate structures in areas threatened by flames from the California fire. Campers, and horses on ranches have also been forced out, officials said.

The blaze, which ignited on Wednesday in a wilderness area northwest of Santa Barbara, has consumed chaparral and tall grass in the Los Padres National Forest, blackening some 1,200 acres (490 hectares), according to tracking website InciWeb.gov.

About 500 firefighters were trying to hold it from exploding out of control as airplane tankers and helicopters dropped water, officials said.

“There isn’t a lot of marine layer (ocean humidity) so not great conditions for firefighting,” Diane Black, a joint incident command manager, said in a phone interview.

Winds drove the so-called Sherpa Fire, named after a ranch near where it started, toward the Pacific coast, leading authorities to evacuate two state beaches and some ranch land, according to information from InciWeb.gov and the Santa Barbara County website.

The blaze also approached the 101 Freeway overnight, forcing authorities to close it until Thursday morning.

In New Mexico, the so-called Dog Head Fire which broke out on Wednesday about 6 miles (10 km) northwest of the town of Tajique has forced evacuations and grown to more than 12,000 acres (4,900 hectares).

It has burned through timber in central New Mexico, pushing heavy smoke toward cities more than 100 miles (160 km) away as flames spread through a largely unpopulated area, fire information officer Peter D’Aquanni said in a phone interview.

Torrance County Sheriff Heath White said his office was evacuating about 200 people.

D’Aquanni said that, as more than 600 firefighters tackle the blaze, winds could shift the flames to the east.

“There’s not many structures in front of that direction if it goes where we think it’s going,” he said.

The National Weather Service has issued heat advisories for Missouri and southwest Iowa, with temperatures in the mid-90s Fahrenheit (35 Celsius), climatologist Bryan Peake said in a phone interview.

(Reporting by Alex Dobuzinskis; Editing by James Dalgleish)