Burning fiercely and choking the air with smoke, the raging California Mosquito Fire has destroyed 46 structures and continues its relentless spread through dry forests in the Sierra Nevada mountains.   

  The blaze — the largest currently burning in California — started amid extreme heat on Sept. 6 and has grown to about 50,000 acres in El Dorado and Placer counties with only 18 percent containment as of Tuesday morning, according to Cal Fire .   

  Flames spread to mountain communities as the blaze grew, destroying more than 22 homes and 21 other buildings, fire officials said.  More than 11,200 people were forced from their homes and 5,800 structures were still threatened Tuesday as the fire raged.   

  As the sun rose Monday, damage was visible along Michigan Bluff Road, where the fire had burned cars, buildings and trees, leaving charred remains as it continued to tear through the landscape, video from CNN affiliate KOVR/KMAX showed.   

  The fire Monday night was pushing deeper into heavily forested areas, where authorities expected an increase in fire behavior amid “historically dry fuels” in the region, Cal Fire fire behavior analyst Jonathan Pangburn said in a Monday afternoon briefing. .   

  Crews took advantage of cooler temperatures and higher humidity in the fire area Monday, but there was still no containment on the northeast side of the fire, officials said.   

  The Mosquito Fire is among several wildfires currently burning across western states, blanketing skies with smoke and prompting air quality warnings across much of California, Washington, Oregon and Idaho.   

  Smoke from the Mosquito wildfire moved across state lines into Nevada, where a video posted by the National Weather Service in Reno showed a wall of smoke falling across the state on Sunday.  The smoke created unhealthy to hazardous air quality in the area and was expected to linger in the Tahoe Basin and Reno area through Monday, the weather service said.

Watch until the end! Smoke from the #MosquitoFire came into Reno/Sparks this afternoon. Smoke is expected to remain in the Tahoe Basin and Greater Reno/Sparks/Carson City/Minden areas through tomorrow. For more information: pic.twitter.com/udHzLFYBYY — NWS Reno (@NWSReno) September 12, 2022 Placer County health officials warned residents of elevated levels of particulate matter in the air, which can be inhaled deep into the lungs and enter the bloodstream.

  Fire smoke can damage the eyes, irritate the respiratory system and worsen chronic heart and lung conditions, according to the Centers for Disease Control and Prevention.  Smoke can be especially dangerous for children, people with heart or lung disease, the elderly and pregnant women.   

  Crews in the Sierra Nevada mountains were among many engaged in grueling battles against raging wildfires this week.   

  Nationally, 93 active large wildland fires have burned about 850,000 acres in several western states, according to the National Interagency Fire Center.   

  Widespread high temperatures across the West – combined with low humidity and lightning strikes – continue to worsen wildfire conditions, fire officials said.   

  Drought-stricken western states are home to large tracts of dry brush that can be turned into fuel for inferno, particularly in mountain communities.   

  In California, crews were battling 12 different fires.  One of them, the Fairview Fire in Riverside County, had burned 28,307 acres by Tuesday after it broke out a week ago.  Crews, aided by lingering tropical moisture and cooler temperatures, were able to raise the fire’s containment to 62 percent.   

  To the north, firefighters also appeared to have a better handle on the mountain fire, which was 65 percent contained to 13,359 acres on Tuesday.   

  In Oregon, the lightning-sparked Cedar Creek Fire has quadrupled in size since last week, burning about 93,000 acres.  As of Tuesday, it was still burning uncontrollably with 0% restriction.   

  In Idaho, the Moose Fire was 127,500 acres and 37 percent contained, according to Inciweb, a clearinghouse for U.S. fire information.  Firefighting efforts were hampered by grounded helicopters for much of Monday as smoke and fog reduced visibility, making flying conditions unsafe, fire officials said.