California wildfire explodes in size as blazes scorch U.S. West

Firefighters unload water hoses during the Detwiler fire in Mariposa, California U.S. July 19, 2017. REUTERS/Stephen Lam

MARIPOSA, Calif. (Reuters) - A wildfire that has forced thousands of Californians to flee their homes exploded in size on Wednesday, threatening a picturesque gold rush town outside Yosemite National Park as dozens of blazes scorched the U.S. West.

More than 2,000 firefighters have contained just 7 percent of the Detwiler Fire, which is approaching the town of Mariposa and tiny communities in the foothills of the Sierra Nevada mountains, the Cal Fire state agency said on its website.

The Cal Fire Strike team leader holds a meeting at Shilling Ranch after authorities ordered evacuations due to the Detwiler fire in Mariposa. REUTERS/Al Golub

The blaze has mushroomed to 48,000 acres (19,424 hectares), an increase of about 23,000 acres (9,307 hectares) compared with the day before. The fire has destroyed 29 structures and is threatening some 1,500 more structures, local media reported.

Firefighters are facing "extreme and aggressive fire behavior" with solid walls of flame and sparks from the main blaze setting spot fires in grasslands, the California Department of Forestry and Fire Protection (Cal Fire) said.

Flames have destroyed eight structures southwest of Yosemite National Park and the fire is threatening power lines to the park, but no one has been injured, Cal Fire said.

A group of evacuees from Mariposa gather in the parking lot at Sierra Vista Presbyterian Church in Oakhurst where an evacuation center is being set up during the Detwiler fire in Mariposa, California U.S. July 19, 2017. REUTERS/Stephen Lam

The small communities of Coulterville and Greeley Hill were ordered evacuated on Wednesday.

Mariposa's 2,000 residents were told to leave town on Tuesday after its power and water links were damaged. In total, nearly 5,000 people are under orders to vacate their homes, officials said.

Many summer vacationers visit Mariposa, which is largely dependent on tourism.

Evacuees Jodi and Don Roark of Bear Valley rest in the parking lot of Sierra Vista Presbyterian Church in Oakhurst where an evacuation center is being set up during the Detwiler fire in Mariposa, California U.S. July 19, 2017. REUTERS/Stephen Lam

The town, taking its name from the Spanish word for butterfly, was founded during the California gold rush in the 19th century and is surrounded by pine-covered hillsides. It boasts the state's oldest law court, built in 1854 in a Greek Revival style and topped with a clock tower.

The town's hospital, called the John C. Fremont Healthcare District, and its 14 patients did not evacuate, at the advice of fire officials, said the facility's interim CEO Matthew Matthiessen.

Moving the mostly elderly patients could endanger their health, he added. "If we can keep them here and limit that stress and they're safe, then that's what we're going to do."

A burned out vehicle is seen near a home destroyed by the Detwiler fire in Mariposa, California U.S. July 19, 2017. REUTERS/Stephen Lam

The California blaze was among 37 active large fires spread across 12 western states as of Wednesday, according to the National Interagency Fire Center's website.

Governor Jerry Brown declared a state of emergency for Mariposa County on Tuesday, dispatching resources to the area.

A burnt vehicle is seen near a home destroyed by the Detwiler fire in Mariposa, California U.S. July 19, 2017. REUTERS/Stephen Lam

(Additional reporting by Al Golub in Mariposa, Alex Dobuzinskis in Los Angeles, Brendan O'Brien in Milwaukee and Ian Simpson in Washington; Editing by Tom Brown, Andrew Hay and Himani Sarkar)

Main street in Mariposa is Highway 140 after authorities ordered evacuations due to the Detwiler fire in Mariposa. REUTERS/Al Golub

A Cal Fire bulldozer makes a safety zone on Shilling Ranch after authorities ordered evacuations due to the Detwiler fire in Mariposa. REUTERS/Al Golub

Flames from a gas line are seen amidst a home destroyed by the Detwiler fire in Mariposa, California U.S. July 19, 2017. REUTERS/Stephen Lam

Charred beverage bottles and cans are seen near a home destroyed by the Detwiler fire in Mariposa, California U.S. July 19, 2017. REUTERS/Stephen Lam

A chimney stands amidst remains of a home destroyed by the Detwiler fire in Mariposa, California U.S. July 19, 2017. REUTERS/Stephen Lam

Remains of a burned out vehicle are seen near a home destroyed by the Detwiler fire in Mariposa, California U.S. July 19, 2017. REUTERS/Stephen Lam

A firefighting truck is seen parked along a firebreak beneath a burning ridge during the Detwiler fire in Mariposa, California, U.S., July 19, 2017. REUTERS/Stephen Lam

Flames from the Detwiler fire burn on a hill near the John C. Fremont Hospital in Mariposa, California, U.S., July 18, 2017. Picture taken July 18, 2017. REUTERS/Stephen Lam

Two firefighters work on a hotspot during the Detwiler fire in Mariposa, California, U.S., July 19, 2017. REUTERS/Stephen Lam

A helicopter loads fire retardent of the Whittier fire along Highway 154 near Santa Barbara. Mike Eliason/Santa Barbara County Fire/Handout via REUTERS

A United States Forest Service firefighter keeps a close eye on flames during a back fire operation on the Whittier fire near Bee Rock off Hwy 154 near Santa Barbara. Eliason/Santa Barbara County Fire/via REUTERS