BRIAN HEAD, Utah - A human-caused wildfire erupted just outside of Brian Head Saturday, prompting an evacuation of the entire resort town, fire officials said.

More than 500 people were forced to evacuate, and highway 143 has been shut down while firefighters battle the flames.

Dixie National Forest tweeted around 8 p.m. structures have been destroyed.

Dixie National Forest is reporting structures have been destroyed. pic.twitter.com/yvLn9Z9z10 — Robert Boyd (@Robertboydfox13) June 18, 2017

Our Robert Boyd tweeted at 8:30 p.m. the fire has grown to over 500 acres with zero percent contained.

The fire has now grown over 500 acres with zero percent contained. — Robert Boyd (@Robertboydfox13) June 18, 2017

The wildfire had burned 350 acres as of 3:30 p.m., according to Mike Melton, with the southwest region of the Utah Utah Division of Forestry, Fire and State Lands.

Melton said the fire reached the town's city limits before 4 p.m.

Great Basin Coordination Center tweeted the fire has grown to 500 acres.

#Brianhead fire is estimated at 500. Mandatory evacuations for the city of Brianhead. — GBCC News and Notes (@GreatBasinCC) June 17, 2017

It added a photograph of the aerial assault on the fire.

Photo provided by Parowan City PD. #BrianHeadFire pic.twitter.com/tQdZ6BrcAH — GBCC News and Notes (@GreatBasinCC) June 17, 2017

Melton said crews are working the fire from the air, and ground crews are trying to protect structures.

He said there are multiple engines from local, state and federal agencies on scene along with multiple air tankers and helicopters. A Type III Incident Management Team has been ordered and will arrive Saturday evening. A Type II team will arrive Sunday around noon.

The Brian Head Fire Marshal's Office says State Road 143 from Parowan to Brian Head has been closed. Residents were asked to evacuate the south side of town.

Authorities have not yet released the cause of the fire, saying only that they believe it was human-caused.

This is a developing story.

Follow our partners at the St. George News for real-time updates on the fire here.