Boise National Fire officials say a wildfire lit over the weekend near Skinnydipper Hot Springs near Banks continued to grow Tuesday because of very hot temperatures and gusty canyon winds.

A rock fall has closed a section of Idaho 55 between Banks and Smiths Ferry.

The rock fall is likely a result of a wildfire burning in the area. High heat loosens soil and burns vegetation that otherwise might provide a more firm foundation on the steep slopes.

“The fire has reached the highway in a few locations, and in other areas is on the steep mountains above the highway,” said David Olson with the Boise National Forest. “Due to the high risk of rocks hitting vehicles, the highway was closed at approximately 4:45 p.m. Tuesday afternoon.”

The closure is in effect from milepost 79 to 82; officials are unsure how long the highway will be closed.

The Banks to Lowman Road is open with a pilot car, so drivers should expect delays.

As of Tuesday afternoon, the fire had doubled in size, growing to about 1,400 acres. The fire has moved into an area about two miles north of Banks on a ridge about one mile above Idaho 55.

Officials say fire crews continue to do a good job on the southeast flank of the Springs Fire, which is about half a mile from the Frazier Creek subdivision, a group of about 18 homes. Homeowners have been warned about the blaze but there have not been any evacuation orders as of Tuesday afternoon. Some engine crews are in that neighborhood. No other structures were reported to be in danger as of 3 p.m.

About 200 firefighters are working on the blaze. Hot Shot crews are putting in firelines in the steep terrain while being supported from the air by helicopters doing water drops and two planes dropping retardant. Fire officials say there is an 3,000 foot difference from the top to the bottom of the blaze.

A Type 1 fire management crew will take over management of the Springs Fire because of the increasing complexity of the fire fighting effort, officials said.

Officials say all of the Boise National Forest is very dry and recreationists need to be very careful with fire. Stage 1 Fire Restrictions will likely be expanded to include the entire Boise National Forest later in the week, which means campfires are only allowed in developed recreation sites.