UPDATE: River Fire Erupts in Nevada and Placer Counties; Thousands Evacuated

PLACER COUNTY (CBS SF) -- A wildfire that broke out near the border between Nevada and Placer counties Wednesday quickly grew to 1,400 acres, forcing evacuations in the town of Colfax and other areas according to authorities.

As of Wednesday night, officials said 35-40 structures have been destroyed. About 4,000 structures were threatened, with half of those in the Colfax area.

The fire -- identified as the River Fire by Cal Fire -- started just after 2 p.m. off Milk Ranch Road and Bear River Campground Road just north of Applegate.

Shortly before 5 p.m., the fire was estimated at 500 acres. 40 minutes later, it's size had doubled to 1,000 acres.

As of shortly before 7:30 p.m., the fire had grown to 1,400 acres, Cal Fire officials said.

It is currently zero percent contained.

• Cal Fire: River Fire Incident Page | Cal OES Evacuation Info | Nevada County Evacuation Map | Placer County Evacuation Map

At around 5 p.m., the Nevada County Sheriff's Office ordered evacuations.

Road closures in connection with the River Fire include State Route 174 at Lower Colfax Road and Bear River Bridge as well as the I-80 eastbound and westbound on- and off-ramps at the State Route 174 separation and Canyon Way/Placer Hills Road.

Earlier Wednesday at around 4:19 p.m., the Placer County Sheriff ordered evacuations in Colfax.

Those who have evacuated can go to a shelter set up at the Auburn Veterans Memorial Hall at 100 East Street in Auburn. That shelter is accepting pets. There is a second shelter established at the Gold Country Fairgrounds & Event Center at 209 Fairgate Road, also in Auburn that opened at 5 p.m. No pets will be allowed there.

The Cal Fire Nevada Yuba Placer unit tweeted video and said the incident commander has requested support for structure defense due to the immediate threat to homes in the area.

The fire is reportedly burning on both sides of the Bear River.

KPIX Sports Director Dennis O'Donnell tweeted video of a plume of smoke from the River Fire near Colfax.

Cal Fire had previously issued a Red Flag Warning for the northeastern part of the state due to gusting winds, high temperatures and low humidity.

• Cal Fire
• Wildfire