A
 fast-moving fire that prompted evacuations near Tahoe injured four 
firefighters, who are now being treated at the UC Davis Medical Center. 
Christie Smith reports. (Published Sunday, July 26, 2015)
Updated at 11:51 PM PDT on Sunday, Jul 26, 2015
A fast-moving fire that prompted evacuations near Tahoe was downgraded Sunday to about 1,500 acres.
Authorities
 reported four injuries on Sunday. Two Cal Fire and two U.S. Forest 
Service firefighters suffered burn injuries. All are being treated at UC
 Davis Burn Center in Sacramento.
Both
 Cal Fire personnel and one USFS firefighters are expected to be 
released from the hospital Sunday night. The remaining USFS firefighter 
is being treated for serious burn injuries.
Cal Fire said 1,800 structures are threatened in Placer and Nevada counties due to the fire.
On
 Saturday, Cal Fire officials said that the Lowell fire scorched roughly
 4,000 acres in the Steep Hollow drainage area west of Alta near Placer 
County in northeast California. But the acreage was reduced due to "more
 accurate mapping," officials said in a tweet, adding that the blaze is 
15 percent contained.
The
 Lowell fire was the second multi-thousand-acre brushfire burning in 
Northern California this weekend, following the 6,900-acre Wragg Fire smoldering between San Francisco and Sacramento.
Access
 to the fire, which sparked at 2:37 p.m. Saturday, is very challenging, a
 Cal Fire representative said, adding that 1,111 fire personnel are 
battling the blaze.
The
 Placer and Nevada County Sheriff’s offices are asking the public for 
help in identifying a vehicle of interest that may have caused the fire,
 Cal Fire said. The 4 x 4 white jeep Wrangler was found in the area 
without a top, no front doors and a black roll bar around 2:30 p.m.
Anyone with information about the vehicle is encouraged to call the Placer or Nevada County Sheriff’s department.
Officials
 evacuated several communities by Saturday evening. Mandatory 
evacuations were underway for Red Dog, Chaulk Bluff and You Bet areas in
 Nevada County. Advisory evacuation was in place for the northeastern 
portion of Cascade Shores.
Chicago Park at Powerhouse Road, Diggins at Alta and Mando Road between Pasquale and Banner are closed, according to Cal Fire.
An evacuation center was opened at the Nevada Union High School on 11671 Ridge Road in Grass Valley, according to Cal Fire.
Cal Fire has activated one of its Serious Accident Review Teams to assess the incident.