RENO - Fire crews battled exhaustion and the calendar on Wednesday as they gained some ground on the 15 fires burning throughout Nevada.
A new one took off overnight between Sparks and Pyramid Lake north of Reno, but quick work held it to about 250 acres and 50 percent containment.
It was earlier thought the fire was a holdover from last week's thunderstorms, but tire tracks found at the site now have investigators believing it was caused by a person.
Many firefighters were brought in from other states to help with the blazes in Nevada and are nearing the 14-day maximum for their tours of duty.
The state's largest fire, the O'Neil complex southwest of Jarbidge, is losing some of its forces because firefighters from Oregon who have reached their 14-day limit are being asked to return home to face the threat of new fires there, incident commander Pat Murphy said.
He said requests for 10,000 firefighters are going unfilled across the West. The six-blaze complex was 55 percent contained at 31,137 acres.
In southern Nevada, firefighters were corralling the 878-acre Trout fire 30 miles northwest of Las Vegas. Some 300 firefighters had achieved 75 percent containment, Bureau of Land Management spokesman Phil Guerrero said.
''The crew supervisors are closely monitoring their firefighters for heat exhaustion and dehydration,'' Guerrero said. ''This is dangerous work under hot and dry conditions.''
As in all cases except the fire north of Reno, lightning is the suspected cause, including three new ones that broke out late Monday around the state.
Those fires, burning near Winnemucca and Caliente, have burned about 4,500 acres combined.
East of Fallon, the Twin Peak fire was only 30 percent contained and continued to grow to 10,000 acres with 100 people on the lines.
Near Ely, the Cherry fire was 80 percent contained at 7,500 acres. The Phillips Ranch fire, at 1,300 acres, was 25 percent contained.
This year's fire season is being called the worst in the West in 50 years. So far in Nevada, 817 fires have burned 464,000 acres.