Update@ 2:00 p.m. PT, July 27:
In a July 27 12:30 PM PT update, CalFire now says the fire is 18,150 acres and is 0% contained. The fire has destroyed 8 residences and 7 outbuildings. It is burning in the Merced River drainage, on both sides of the river, with a rapid rate of spread in multiple directions. There are accessibility problems due to steep and rocky terrain.
As of their 12:30 update, the fire had not spread a great deal over the previous 12 hours, however, as of 2:00 p.m., satellite photos show a large plume of smoke from the fire being pushed by a wind out of the south. This would indicate that additional acres are most likely being consumed on the north side of the fire, east and southeast of Coulterville. This corresponds with the thermal imagery in the map below.
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A fire that started Friday afternoon in Mariposa County in California is now well over 16,000 acres and growing. CalFire reported that acreage figure Saturday night, but at the rate it is spreading, it is probably much larger now. CalFire said that 2,000 residences are threatened in the communities of Midpines, Mariposa, Greeley Hill, Coulterville, Bear Valley, and Mt. Bullion Camp.
The fire is about 8 miles west of El Portal, one of two entrances into the west side of Yosemite National Park. Electricity was turned off in a large area, including the park, to protect firefighters working near the lines.
There have been no recorded fires in the area for over 100 years, so the fuel loading is very heavy. CalFire is planning a large burnout ahead of the fire in an attempt to slow it down. A spokeswoman said the cause of the fire was “definitely target shooting,” but she would not elaborate.
Some excellent photos are at GoldRushCam.
HERE is a link to a web camera in Yosemite from Turtleback Dome looking west. Turtleback is about 12 miles southeast of El Portal. It is pretty hazy there, but there appears to be smoke in the distance. The site also provides air quality information and shows a large increase in particulate matter over the last 48 hours in the park.
The map below shows heat, in red, orange, and black, detected by satellites, with the red areas being the most recently burned. The yellow line is the latest perimeter uploaded by the incident management team. The green areas are national forest, and the purple is Yosemite National Park. Click on the map to see a larger version.