Soberanes Fire aerial/VIIRS/MODIS data — 0730 8/9

It took me a while to get the MODIS and VIIRS data sets to download, but I finally have all three IR maps and the official fire perimeter.

First, last night’s and the nigh before’s fire perimeter overlaid on the same Google Earth map:

In the west, we see the long skinny expansion along the good side of the fire break that we saw on the IR images from yesterday. That’s almost certainly back burning. We see some small further burning on the wrong (south) side of the fire break. Idon’t know what that is. And we see the fire itself spreading in southeastely and southwesterly directions:

In the east we see the same advances towards teh southeast that we’ve been seeing:

Here’s the aerial IR map, and it’s more than a little confusing:

The confusing part is the large areas indicated as intense heat that have been cold for days in the previous maps. I’ll put this down to a mapping error.

In the west we see a lot  more heat on the wrong side of the fire lines than we saw in the fire perimeter map. Back burns? Wild fire? I don’t know:

In the east, it’s hard to sort out the real intense heat from the mapping errors. One clue is that there should never be red dots in the middle of red-shaded areas. We know this area was extensively back-burned yesterday:

Here’s what MODIS has to say after two overnight passes:

In the west we see a lot of activity on the wrong side of he break, movement to the east, and the continued process of the central and the western fires merging once more:

In the east we see the central section expanding both easterly and westward. In the part of the fire area near the General Store, nothing caught MODIS’s eyes:

The VIIRS satellite data is harder than usual to interpret, because by the time that the download worked, the latest data was more than 12 hours old, hence there are no red squares:

In the west we see burning outside last night official lines, even with old satellite data:

In the east it looks like the fire’s advancement to the southeast is taking place on a broad front:

The orange lines are the dozer fire breaks that were in as of 7/30, plus one that I added by hand. The pink lines are the ones that were planned as of that date. The fat black lines are the outlines of the fire’s perimeter on the official Cal Fire maps from last night.

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.

No MODIS images from yesterday, but here’s a VIIRS daytime one: