The new official Cal Fire perimeter map, as compared to yesterday’s:
For the first time, the perimeter has gotten smaller in some places. There was one place yesterday that was so far out of line with the VIIRS data that it had to be an error, and my guess is the other contractions were the result of errors in yesterday’s outline, not as a result of today’s. The polygon that defined yesterday’s outline was les detailed than usual.
In the west:
The yellow area was in yesterday’s map, but not in today’s. The light red was in both. The dark red is only in today’s. The expansion to the doutheast that we saw on yesterday’s VIIRS maps is evident.
In the south-ventral:
That big yellow patch is the place that looked to be in error yesterday. There is expansion to the south, and also towards the east.
In the Cachagua area:
We saw a lot of back burning in this area yesterday, and it is reflected on the map.
I’ve got both VIIRS and MODIS data from last night’s passes. I’ll give you the MODIS data first, and the VIIRS next. Feel free to skip the MODIS data and go right to the good stuff. MODIS isn’t all bad in comparison to VIIRS’ we do get more frequent looks with it.
The overall MODIS map:
And the regions we’re watching:
In what has become a rare thing recently, be have the MODIS radiant power map:
I am not finding this of much use, since it’s so hard to identify the age of the squares by turning the power map on and off in Google Earth, except at the edges where they are usually low power.
OK, here’s what you’ve been waiting for, VIIRS high-resolution data:
And the details:
Let’s zoom in on the area that looked like it could be a wildfire approaching houses with the MODIS data, but looked more like a back burn to protect the fire lines with the VIIRS data. I’ve added the Cachagua General Store for a reference point:
On FaceBook, Lauren Keaton has this to say: “Intentional burns, yes. My home is in the middle of them but fine. They did burn lines right around it and at the dozer lines up to the dam.” Thank you, Lauren.
With the exception of Lauren’s information above, my remarks about what is wild fire and what are back burns are guesses based on the location and the patterns. I could be wrong. If you think I am, please let me know.
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.
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.
Last night’s VIIRS image shows the fire outshining some towns in the Central Valley:
The line on the upper right is the California/Nevada border.
Yesterday’s visible light MODIS image shows smoke going almost to Santa Barbara:
Zooming in a bit:
In the MODIS UV-IR image, you can see the fire’s heat in the south-central portion, and near Cachagua:
This morning’s numbers: 53,690 acres; 35% contained.
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