A fire burning at the edge of Crater Lake National Park exploded overnight, pushing its way farther into the park and prompting several trail closures, according to fire officials.

The Spruce Lake fire surged from 194 acres Tuesday to about 1,400 acres today, egged on by Tuesday afternoon winds that blew east across a landscape baked by triple-digit heat.

"The winds were picking up the embers from the fire and blowing those embers up to a mile away, which then fell and lit new fires," said Blanket Creek fire public information officer Koshare Eagle.

The surge has prompted a closure on the Pacific Crest Trail between the Lightning Springs Trail and Red Cone Camp. Bald Crater Loop Trail has also been closed from its intersection with the Pacific Crest Trail to Bert Creek Trail, which has also been closed.

The fire has now pushed into Crater Lake National Park and is considered 5 percent contained. The Blanket Creek fire burning nearby has grown to 1,369 acres and is 7 percent contained.

There are 744 personnel assigned to fight the blazes, both of which were sparked by lightning. Three firefighters have fallen ill due to the heat wave that's frying much of the state.

The National Weather Service has issued an excessive heat warning until 8 p.m. Friday. Temperatures from the high 90s to 115 degrees are expected during the day, then dipping down to the 70s overnight.

A red flag warning is also in effect until 9 p.m. Thursday because of unstable conditions that could contribute to additional fire starts.

— Reach reporter Ryan Pfeil at 541-776-4468 or rpfeil@mailtribune.com. Follow him at www.twitter.com/ryanpfeil.