Containment on the Grasshopper Fire has increased to 47 percent as firefighters continue strengthening and securing control lines ahead of an expected shift to warmer, drier and windier conditions.

Crews have made the most progress in the fire’s northeastern portion, where extensive mop-up has been completed and no new fire activity has been reported for several days.

On the northwest side, an unmanned aircraft system is supporting firing operations and using infrared technology to detect remaining heat. The technology is helping crews target mop-up efforts and eliminate unburned pockets between the fire and established control lines.

The fire area along Highway 35 remains secure. Crews are patrolling for isolated heat while falling modules address hazardous trees.

Along the northern boundary, firefighters continue to work on remaining heat and substantial mop-up needs. Structural resources remain active in Timber Gulch, Fifteenmile Road, Hix Road and Friend Road. National Guard personnel are assisting with structural mop-up in the Friend Road area.

On the eastern edge, hand crews are continuing to secure fire lines. An interior island of unburned vegetation remains active and is producing smoke, but the fire is burning well within the established perimeter. Smoke is expected to continue as the remaining fuels are consumed.

Crews on the southeast portion have made progress strengthening control lines, although additional work is needed to fully secure the area. In Shadybrook, firefighters continue structural preparation, protection planning and monitoring.

The southern edge of the fire remains contained. On the southwest corner, highline-capable equipment has been ordered and is expected to arrive in the coming days. Fire spread in the area remains slow as crews work to tie the fire into existing trail systems.

Weather conditions are expected to become more challenging overnight. Winds are increasing from the northwest Sunday evening as a drier air mass moves into the area around midnight. Relative humidity is expected to decline overnight and into Monday as temperatures rise.

An inversion is forecast for Monday morning, followed by a rapid drop in humidity as the inversion lifts. Terrain-driven winds could continue to test control lines.

Fire officials said crews have made significant progress strengthening containment lines ahead of the expected weather change.