The Latest on a wildfires burning in the U.S. West (all times local):

7:30 a.m.

At least 100 homes in Northern California have been evacuated as a wildfire charged through inaccessible terrain and climbed out of a steep canyon along the middle fork of the American River.

People living in a rural subdivision 50 miles northeast of Sacramento fled Tuesday as firefighters braved triple-digit temperatures to battle the blaze.

Placer County sheriff's spokeswoman Dena Erwin says homes near Todd Valley between the cities of Foresthill and Auburn were evacuated as the fire quickly grew to roughly 300 acres.

California Department of Forestry and Fire Protection spokesman Daniel Berlant tells Sacramento station KCRA-TV (http://bit.ly/299QJlK ) that the evacuations were called because the community only has one way in and one way out.

No injuries or damage had been reported by Wednesday morning.

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6:45 a.m.

A growing network of online cameras installed on forested mountaintops is changing the way crews fight fires by allowing early detection that triggers quicker, cheaper and more tactical suppression.

The network of roughly 20 high-definition cameras being installed around the Lake Tahoe region can pan, tilt and zoom into fires. They can rotate 360 degrees. And the cameras even have night vision, to supplement human lookouts that only work during daylight hours.

Fire officials say the cameras will augment — and not replace — human fire spotters who climb high towers armed with only a radio and binoculars, scanning the forest for faraway smoke.

They hope to install the internet-ready cameras throughout California and other Western states.