Lightning storms accompanied by gusty winds could start more wildfires in the region Sunday and Monday, the National Weather Service warns.

Weather officials have issued a red flag warning in effect from 1 to 11 p.m. Sunday in the Siskiyou Mountains and Southern Oregon Cascades, and a fire weather watch has been issued for most of Monday in the same areas. Both advisories mean critical fire weather conditions are occurring or about to.

Forecasters predict abundant lightning on dry fuels in higher terrain, hindering firefighters' efforts to contain two fires burning in northeastern Jackson County.

"Lightning and high fire danger will likely result in new fire starts," a National Weather Service message reads. "Gusty thunderstorm winds could contribute to fire spread. Even with some rainfall, initial attack resources could be overwhelmed and holdover fires are possible."

The Spruce Lake fire had grown to 5,000 acres Friday night, and only 5 percent of the perimeter had been contained by firefighters, according to InciWeb, a site that tracks fires on federal and state lands.

The lightning-caused fire was discovered July 29 on the west perimeter of Crater Lake National Park and has been burning southeast toward the caldera, prompting the National Park Service to close West Rim Drive from the North Junction to Rim Village.

The Pacific Crest Trail is closed from the south park boundary to Highway 62 and from the intersection of Dutton Creek Trail north to the North Entrance Road.

Most of the rest of the trails on the west side of Crater Lake are also closed, including Union Peak, Stuart Falls, Pumice Flat, Boundary Springs, Bald Crater Loop, Bert Creek, Discovery Point, Lightning Springs, and the Rim Trail from Discovery Point to North Junction.

Rim Village and trolley and boat tours remain open and running.

The nearby Blanket Creek fire, also caused by lightning, had burned 3,852 acres as of Friday, according to the most recent information available. It was discovered July 26 about seven miles east of Prospect on the High Cascades Ranger District of the Rogue River-Siskiyou National Forest. About 14 percent of the perimeter had been contained, InciWeb says.

The fires hit during the Upper Rogue and Crater Lake's busy tourist season. The national park last year drew more than 700,000 people, breaking attendance records.