Wind and 106-degree heat hampered firefighters' battle against two wildfires in the Desert National Wildlife Refuge in southern Nevada.
A 21,120-acre fire centered on the Sheep Mountains about 50 miles north of Las Vegas was 50% contained, with full containment expected Tuesday, a fire official said.
No containment figure was available for a 2,500-acre blaze around Gass Peak about four miles north of Las Vegas.
The fires threatened a 1.5-million-acre endangeredspecies refuge that is home to desert bighorn sheep and desert tortoises.
The refuge, established in 1936, is one of the largest intact habitats for desert bighorn sheep in the Southwest and the largest national wildlife refuge in the Lower 48.
Of the two biggest wildfires of the year in northern Nevada, the 79,858-acre Suzie fire near Elko was 90% contained and the 10,400-acre Sneekee fire was fully contained.
In the Reno area, officials estimated that the Sierra-Tahoe complex of 16 wildfires was 95% contained. It had threatened hundreds of homes and scorched 13,323 acres.
In all, more than 140,000 acres of the state have been blackened since lightning began sparking dozens of fires June 23.