Wildfires in California spotted by Sentinel-2A

Wildfires were raging in California this summer. Let's see if we can spot some of them in Sentinel-2A images with the new Sentinel-Playground by Sinergise.


The combination of the SWIR and NIR bands of Sentinel-2 or Landsat enables to produce accurate maps of burnt areas. The SWIR band is sensitive to the water content in the soil and vegetation, while the NIR band is sensitive to the vegetation health (photosynthetic activity).


In addition, the radiance measured by a spaceborne sensor in the SWIR wavelengths increases if the surface is very hot (as taught us Prof. Planck in Hawaïï).


As a result, a simple color composite of bands SWIR/NIR/Red gives a stunning view of burnt areas and can highlight ongoing fire areas if the smoke is not too opaque.


In Coalinga, the Mineral Fire burnt nearly 3000 ha close to the city of Coalinga.

Mineral wildfire near Coalinga, Californa USA. Time series of Sentinel-2A images (RGB color composite of bands SWIR/NIR/Red = 12/8A/4)


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Snow and Fire in the Dragon mountains

NASA's blog "Image of the Day" recently featured two beautiful MODIS images of the snow cover in Lesotho. In late July Lesotho experienced its heaviest snowfall in two decades. The snow is not uncommon in Lesotho given that over 80% of the country lies above 1800 m (wikipedia). However the frequency of such snow events has been reducing over the past decades due to the ongoing climate change. As a result the shepherds are less accustomed to the snow conditions so that "a severe storm like the one in July 2016 has greater potential to kill sheep and shepherds" [1]. Continue reading