Really good news from the overnight MODIS passes. The fire, which had been quite active at night for the past few days, was pretty quiet. Even better, there were no new hotspots in the east. The new activity is moving in a direction that does not immediately threaten structures.
Here’s the same MODIS data with the fire boundaries marked to reflect the official Cal Fire data as of midnight last night:
From this it is likely that the very southern hot spots from yesterday were back burns. The dozer line marking are still from the 30th. I’ll try to get an update later today, but Cal Fire is posting new Google Earth dozer line data sporadically. Orange is completed, pink is planned. I can tell you from looking at today’s operations maps that great progress has been made extending the fire breaks to the south, well off the area pictured above.
How to read the MODIS/VIIRS heat indications: The size of the square represents the nominal margin of error. The fire could be anywhere in the square, not just at the center. Dark red squares were detected less than six hours before the data set was created. Light red squares were detected less than twelve hours before the data set was created. Orange squares were detected less than 24 hours before the data set was created. Yellow squares were detected less than six days before the data set was created. When the squares overlay other objects, the color of the square changes somewhat, but the color of the dot in the middle does not. So look at the dot if you’re uncertain what color the square should be. Since the fire is now over six days old, some of the early detections have dropped off the map. MODIS makes mistakes, sometimes missing outbreaks, and sometime misplacing them outside the nominal margin of error. It is also a snapshot of the activity at the time the satellite is overhead, and will definitely miss flare ups between passes. MODIS can’t tell the difference between wildfires and intentional back burns.
Yesterday’s visible band image from MODIS:
You can see that most of the smoke seems to be coming from the southeast and southswest portions of the fire.
In the infrared and ultraviolet:
You can see the flames in the infrared band, but they are weaker than the day before and the day before that. The brown/gray area shows where the fire has burned off most things that contain chlorophyll, which reflects strongly in the infrared.
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