The Mosquito Fire in the foothills east of Sacramento has spread to nearly 65 square miles (168 square kilometers), with 10 percent containment, according to the California Department of Forestry and Fire Protection, or Cal Fire. “Cooler temperatures and higher humidity helped reduce fire activity,” but stronger winds allowed flames to push north and northeast, according to a Cal Fire incident report Sunday. More than 5,800 structures in Placer and El Dorado counties were threatened, and about 11,000 residents of communities including Foresthill and Georgetown were ordered to evacuate. In Southern California, cool temperatures and rain brought respite to firefighters battling the massive Fairview wildfire about 75 miles (121 kilometers) southeast of Los Angeles after sweltering heat last week. The 44-square-mile (114-square-kilometer) fire was 45 percent contained Sunday. The fire has destroyed at least 30 homes and other structures in Riverside County. Two people died while escaping the flames last Monday. A helicopter assisting with operations on the Fairview Fire crashed into a residential yard while attempting to land at a local airport Saturday afternoon, fire officials said. The injuries to the pilot and two others were not critical. Pacific Northwest Wildfires The southern part of the state welcomed cooler weather over the weekend as a tropical storm drifted off the Pacific coast and weakened, helping end temperatures that nearly overwhelmed the state’s power grid. Thunderstorms and the risk of flooding remained in mountainous areas of greater Los Angeles on Sunday. But after Hurricane Kay made landfall in Mexico last week, it quickly downgraded and weakened further until it was largely gone, forecasters said. To the north, Kay’s remnants caused flooding Saturday that stranded about 40 vehicles and closed a section of State Route 190 in Death Valley National Park. The park was still being cleaned up from flooding five weeks ago that closed several major roads. In Washington state, fire officials were scrambling to secure resources to battle a wildfire that broke out Saturday in the remote Stevens Pass area that sent hikers fleeing and forced evacuations of mountain communities. There was no containment Sunday of the Bolt Creek Fire, which had burned nearly 12 square miles (31 square kilometers) of forest about an hour and a half east of Seattle. “The fire will continue to advance in unmanned areas. With limited resources, there will only be spot protection while resources continue to be mobilized to the fire,” an incident report said Sunday morning. California’s Mosquito Fire has covered much of the Northern Sierra region in smoke. California health officials urged people in affected areas to stay indoors where possible. Tour de Tahoe organizers canceled the annual 72-mile (115 km) bike ride planned for Sunday around Lake Tahoe because of thick smoke from the fire — more than 50 miles (80 km) away. Last year’s ride was canceled due to smoke from another large wildfire south of Tahoe. The cause of the mosquito fire remains under investigation. Pacific Gas & Electric said unspecified “electrical activity” occurred near the report of the fire Tuesday. Scientists say climate change has made the West hotter and drier over the past three decades and will continue to make weather more extreme and wildfires more frequent and destructive. Over the past five years, California has experienced the largest and most destructive wildfires in the state’s history. And the rest of the West has not been immune. There were at least 18 large wildfires in Oregon and Washington, prompting evacuations and targeted power outages near Portland as the challenge of dry and windy conditions continued in the region. Vast areas of western Oregon choked by thick smoke from wildfires in recent days were expected to see improved air quality Sunday thanks to the return of overland flow, Oregon Public Broadcasting reported. South of Portland, more than 3,000 residents received new evacuation orders because of the 134-square-mile (347-square-kilometer) Cedar Creek fire, which has been burning for more than a month in Lane and Deschutes counties. Firefighters were protecting remote homes in Oakridge, Westfir and surrounding mountain communities. According to the Northwest Interagency Coordination Center, this weekend there were more than 400 square miles (1,035 square kilometers) of active, uncontrolled fires and nearly 5,000 people on the ground fighting them in the two northwestern states.