(AP) — A Northern California wildfire destroyed 10 homes and threatened 800 more, forcing residents to evacuate as a series of wildfires throughout the U.S. West drive people from their houses, authorities said Wednesday.

The blaze that started Tuesday near Oroville is among a number of wildfires across the region, parts of which are struggling with triple-digit temperatures.

They included fires in and around California’s Yosemite National Park that closed a popular road into the park, shuttered the iconic Wawona Hotel and evacuated nearby towns.

The latest wildfire is about 20 miles (32 kilometers) east of Oroville Dam, the nation’s tallest. Tens of thousands of residents downstream fled when the dam’s spillways crumbled earlier this year and led to fears of catastrophic flooding.

Months later, a wildfire about 15 miles (24 kilometers) south of the dam destroyed 41 homes in July.

A cause of the new fire has not been determined. The California Department of Forestry and Fire Protection said crews “experienced rapid fire development, dangerous rates of spread and high temperatures” Tuesday. Similar conditions were expected Wednesday as more firefighters arrive to battle the blaze.

Meanwhile, some two dozen fires are burning in southern Oregon, leading more than 4,500 residents to evacuate. The area burning in the state is roughly equivalent to half the state of Rhode Island, and the largest fire is only partially contained after lightning ignited it in mid-July.

Smoke from all the blazes has converged on Portland, several hundred miles away, and has obscured the iconic view of Mount Hood and triggered air quality warnings.

In Montana, authorities have ordered about 1,200 homes to evacuate near Seeley Lake, a popular destination for boaters, anglers and hikers about 100 miles (161 kilometers) northwest of Helena.

In Glacier National Park, smoke from wildfires has led officials to close the historic Lake McDonald Lodge for the season. Earlier this month, the backcountry Sperry Chalet shut down because of the same fire.