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Posted on October 5th, 2021

Our Changing Landscape – The Start of the Caldor Fire

In this monthly feature, we span the globe to examine Our Changing Landscape with a time series of medium-resolution PlanetScope satellite imagery. The PlanetScope constellation dates back to 2016 and collects hundreds of millions of square kilometers of 4, 5 and 8-band 3-meter imagery daily! Last month we checked out historic and tragic flooding in western Germany, and for this fall edition of Our Changing Landscape we turn our attention to another historic weather event, this time a wildlife in northern California’s Sierra Nevada Mountain range, the Caldor Fire.

Click on the image above to see an animation of 3-meter natural color PlanetScope imagery collected over the Sierra Nevada Mountain range in California, USA on August 14, 16, 17 and 23, 2021. In the first image from August 14th, there is no apparent active fire here though there is certainly thick smoke in the area which makes the image appear to have an underlying white tone. By August 16th, you can see that several large fires are burning near the center of this area. By August 17th, there are active fires in both the central part of the image and to the east. And then by August 23rd, you can see active fires to the west with huge amounts of destruction left in the wake of the Caldor Fire to the east. It is interesting (and depressing) to see how wildfires literally jump across a landscape from east to west and back again, all the while leaving behind a charred and desolate landscape. (Images Courtesy: © Planet 2021)

The PlanetScope Microsat Constellation

PlanetScope is a constellation of more than 150 microsats referred to individually as Doves. Each Dove is able to collect up to 20,000 square kilometers (sq km) per day of 3-meter (m) 4-band multispectral (i.e. blue, green, red and near-infrared [NIR]) imagery; and newly launched SuperDoves collect 8-band multispectral adding in valuable red-edge spectral data. Across the constellation, PlanetScope is archiving more than 200 million sq km of medium-resolution imagery a day, making it the go to source for daily imagery over most locations. This massive archive dates back to 2016, offering the most complete and continuous record of spatial data on the planet since the start of the constellation’s ongoing launch schedule. Collecting 3-meter multispectral imagery is the equivalent of ‘high-resolution’ multispectral data imaged by a 75-centimer (cm) satellite (as this satellite would feature 75-cm panchromatic and 3-m multispectral), making PlanetScope an extremely competitively priced option at just $1.80 per sq km. With well registered images and nearly daily collections of most locations, PlanetScope is the ideal imagery source for this current-events focused series, Our Changing Landscape.

The Start of the Caldor Fire in Northern California

As I am sure most/all of our readers are aware, the ongoing and historic drought in California, which is fueled by human-induced Global Climate, has significantly escalated the risk of rapidly spreading wildfires that feed off dried timber and brush in combination with near 0% relative humidity. At the time of drafting this article in early September the Cal Fire incidents page listed 7 active fires of interest as well as 11 more fires which were not of interest.

The Caldor Fire is reported to have started on August 14, 2021 in a remote location at the central-western edge of the Sierra Nevada range between Grizzly Flats and Omo Ranch – and nearly equidistant between Lake Tahoe and Sacramento. As of September 1st, the Caldor Fire had spread rapidly to the east, burning just over 204,000 acres with 20% containment. In fact, the wildfire was threatening some 20,000 structures in the Tahoe region with mandatory evacuations spreading all the way to the Nevada border. Now it is time to turn to the 3-meter PlanetScope archive which appears to have captured the early hours of the Caldor Fire in mid-August.

If you would like to find out more about using 3-meter PlanetScope imagery for your academic studies, engineering projects or any landscape analysis, let us know at or (303) 993-3863.

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