Low humidity will aggravate firefighting conditions for two blazes in western Wyoming and one in the southcentral part of the state that have burned over more than 70 square miles, according to the interagency inciweb website on Saturday.

The areas are under Red Flag Warnings -- critical fire conditions of strong, low relative humidity and warm temperatures -- for Saturday if not early next week, and the estimated containment dates for the fires are Oct. 15 at the earliest.

The Roosevelt fire about 15 miles south of Bondurant has grown to 36,600 acres -- 57.2 square miles -- with winds pushing the fire south in timber, brush, grass and sage.

This fire with an unknown cause was first observed Sept. 15 and is now 15 percent contained.

The 571 firefighting personnel are building direct lines and bulldozers, and are trying to prevent the fire from moving further into the Rolling Thunder or the Hoback Ranches subdivisions which are still under evacuation orders. Likewise, air resources will continue to support defense of structures and line construction efforts

Crews will continue to create defensible space in the subdivisions and plan for evacuation of the subdivision on the north/east side of U.S. Highway 189/191.

There is high growth potential for the fire Saturday. Diminished winds, slightly lower temperatures and somewhat higher relative humidity will produce more moderate spread and growth potential through Sunday.

Increasing winds and temperatures and lowering relative humidity will cause high spread and growth potential. Shifting wind directions will return the growth potential to the northeastern flank.

On Tuesday, decreasing winds with lowering temperatures and higher relative humidity will produce more moderate spread and growth potential, and shifting wind directions will return the growth potential to the eastern and southeastern flanks.

The Marten Fire in the Bridger-Teton National Forest about 13 miles east of Afton has grown to 5,260 acres -- 8.2 square miles -- is burning in timber and brush with uphill runs, backing, flanking and short crown runs likely in mixed-conifer stands of trees.

The fire, which is human caused, started Sunday and is now 5 percent contained.

The 360 personnel are building a secure line, using aerial resources to slow the fire growth where possible, and are concentrating on keeping the fire from progressing to the east and west of the main fire.

The Greys River Road is closed south of Sheep Creek/McDougal Gap Road, as are other roads in the area.

Red Flag Warnings are predicted for Saturday and Sunday. Temperatures are expected to rise, with continued low humidity and persistent winds over the fire area for the foreseeable forecast.

The Ryan Fire south of Encampment straddles the Wyoming-Colorado border, and has grown to 2,986 acres -- 4.7 square miles -- and is zero percent contained.

It is burning in beetle-killed lodgepole pine and spruce. The pine trees are 40 percent to 50 percent dead, and abundant downed timber is available to support surface-to-crown fires.

The fire started Sunday and its cause is unknown.

The 218 firefighting personnel are focusing on protecting structures.

Evacuations are in effect for campers, hunter camps, and logging operations in the Routt and Medicine Bow national forests.

While the temperatures are moderate in the upper 60s to lower 70s, a dry air mass remains in place with the relative humidity bottoming out in the upper single digits and lower teens Saturday.