For a second day, extreme heat and erratic winds are making things especially dicey for crews battling a 30,000-acre wildfire that's racing through rugged canyons and bone-dry high desert land near San Bernardino, Calif.

The Bluecut Fire, sparked Tuesday morning, is threatening tens of thousands of homes. With its explosive behavior, fire managers are giving no indication when evacuees will be safe to return home to assess damages. Veteran firefighters and career fire managers have said the blaze is behaving like nothing they've ever seen.

"It hit hard, it hit fast, it hit with an intensity that we haven't seen before," says Mark Hartwig, the San Bernardino County Fire Chief.

Stopping — let alone putting out — a fast-moving fire like this is impossible without a serious change in the weather. And there's no sign of that coming, with red-flag warnings for extreme wildfire danger in effect at least through Thursday night.

Fire officials have yet to give an estimate on the exact number of structures lost, but it's expected to be high.

"There will be a lot of families that come home to nothing," Hartwig says. "If there's a bright side, there are some homes that were saved."

Some of the worst damage is feared to be along Highway 138 near Interstate 15, a primary east-west route linking Los Angeles to Las Vegas that remains closed. In that vicinity, a historic Route 66 diner known as the Summit Inn is reported to have burned to the ground. According to the Los Angeles Times, the cafe, said to have been frequented by Elvis Presley, is now " indistinguishable rubble."

An estimated 80,000 or more people were instructed to evacuate, but as NPR's Nathan Rott tells All Things Considered, it's not clear whether everyone has been heeding that warning. As with a lot of major fires, some residents are apparently defying orders and staying behind, trying to save their homes.

"From a firefighter's perspective, that presents huge problems," Rott reports. "You have people trying to evacuate at the last minute blocking roads and [then] you have people [who] need protection and houses."

The Bluecut Fire has quickly become one of the nation's top-priority wildfires. A federal team is preparing to take over managing it, as resources pour into California from around the country. Gov. Jerry Brown has declared states of emergency in three counties this week, including San Bernardino.

Copyright 2016 NPR. To see more, visit http://www.npr.org/.