Crews are working to put out a wildfire that, after starting small on Tuesday, grew quickly on Wednesday in the North Fork area of the Shoshone National Forest.

The June Fire is located about 1.5 miles south of U.S. Highway 14/16/20 and the UXU Ranch in the June Creek drainage.

The fire was estimated at 5 acres Wednesday morning, but Shoshone officials said it had the potential to grow. By around noon, it was estimated at 100 acres and it put up a large column of smoke in the afternoon as it continued burning through dense, beetle-killed tree stands.

The 20-person Wyoming Hotshots crew and a light helicopter arrived on scene Wednesday morning, joining a Shoshone fire engine and fire crew in the effort to extinguish the wildfire. Shoshone officials initially said they believed the fire could be managed with those resources, but more firefighters and equipment were later requested.

“It was pretty fast growth,” said Shoshone Fire Information Officer Olga Troxel.

By Wednesday evening, two bigger helicopters, two air tankers — which can be used to drop retardant and help protect structures — a couple fire engines and a more advanced initial attack crew had joined the fight, Troxel said. She said there were about 100 personnel on the fire Wednedsay night. Meanwhile, three more 20-person hotshot crews and an incident management team were heading to the North Fork to help.

The estimated fire size of 100 acres was something of a best guess, Troxel said.

“Because it’s so smoky, they’re having trouble estimating,” she explained.

Troxel noted that the intent is to fully suppress the fire, which is relatively close to the developed North Fork corridor.

“Everybody’s working on structural protection right now,” she said.

Fire managers say they're still investigating the blaze's cause. 

A Wednesday morning news release from the Shoshone noted the low humidity and warm temperatures in the forecast for the coming days could lead to fire growth.

Forest visitors traveling on the highway are asked to use caution when driving through the area and to be on the lookout for firefighting equipment. Fire managers also reminded the public that is dangerous to firefighters and illegal to fly a drone over a wildfire. Troxel said the safety of firefighters and the general public is the No. 1 priority of fire managers.

The June Fire is the second to start on the Shoshone this week.

On Monday, an abandoned campfire caused a 3-acre wildfire in the southern part of the forest, about 9 miles southwest of Lander. A wildland fire engine and one hand crew from the Shoshone, two air tankers from Riverton and a light helicopter from Casper quickly contained it.

Forest officials reminded Shoshone visitors to never leave a campfire without making sure it’s completely out.

Fire restrictions have been implemented on local Bureau of Land Management lands, but not in the higher-elevation Shoshone, where the air is generally cooler and the terrain wetter.