A wildfire ripped through more than 4,000 acres near Moab, but evacuation orders in the area were relaxed Thursday.

The Porcupine Ranch fire was just one of several blazes firefighters were racing to control this week.

An afternoon lightning strike ignited the fire about two miles east of Castle Valley and forced the evacuation of the Miners Basin area Wednesday and the evacuation of 20 homes near Bald Mesa on Thursday, said Jason Curry with the Utah Division of Forestry, Fire and State Lands.

The structures in Miners Basin were uninhabited, and despite the fire's growth, most people were allowed to return to their homes near Bald Mesa by Thursday night, officials said.

"We're off to the races with this fire," Curry said. "But not too many people have been affected."

The fire exploded from 200 acres Wednesday to more than 4,000 acres Thursday, because of steep terrain and heavy fuel.

"There's a heavy fuel load. It's been quite some time since a fire has moved through the area," Curry said. "And with the steep terrain, the fire just moves uphill during the day."

The fire was about 5 percent contained Thursday night. A total of seven Hotshot crews along with helicopters and planes were expected to battle the blaze today.

Visitors at the Mason Draw and Warner campgrounds were evacuated Wednesday after the fire jumped La Sal Loop Road. That road remained closed Thursday between Castle Valley and Geyser Pass. Sand Flats Road also was closed Thursday.

Near Vernal, the Split Top 1 fire torched nearly 420 acres about three miles north of the Dinosaur National Monument visitors center Thursday. Helicopters and firefighters were trying to stop the fire's movement on the north and west flanks.

"The fire is burning entirely within the Dinosaur National Monument boundaries," National Park Service spokeswoman Carla Beasley said in an e-mail.

Meanwhile, crews continued to get the upper hand on wildland fires in Tooele and Salt Lake counties Thursday.

The Corner Canyon fire in Draper was completely contained Thursday night, just days after the 808-acre fire threatened homes and forced evacuations along the east bench.

"It won't be out," said Kathy Jo Pollock of the U.S. Forest Service. "There will still be some smoke, but we'll have a line around it."

The cause of the fire remained under investigation, though it was believed to be human caused, officials said. Investigators have gone through tips from the public and have obtained photographs of the area where the fire started.

"We recovered some potential evidence," Curry said. "It's too early to say if it's related to the fire or not."

The area where the fire started was "pretty busy," Curry said. He said investigators are asking for tips on any vehicles, bikes or people seen in the area around noon Monday. Some potential witnesses to the fire's start are still being questioned, he said.

Anyone with information is urged to call the Unified Fire Authority at 801-743-7100.

Firefighters inched closer to containment of the 775-acre Gate Narrow fire burning two miles east of Terra, Tooele County, this week.

The fire was sparked Monday by a vehicle in the area and threatened several ranches and structures for a time, officials said. The fire was about 70 percent contained Thursday, with full containment expected today.

Crews were being shuttled in Thursday to rough, rugged and steep terrain where the fire was burning, and more resources had been ordered. Rocky Mountain Power was working to restore power to the area, said BLM spokeswoman LaCee Bartholomew.

Contributing: Aaron Falk

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