Burn Area Index (BAI)
"The Burn Area Index (BAI) uses the reflectance values in the red and NIR portion of the spectrum to identify the areas of the terrain affected by fire.
BAI = 1/((0.1 -RED)^2 + (0.06 - NIR)^2)
Red = pixel values from the red band
NIR = pixel values from the near infrared band
Reference: Chuvieco, E., M. Pilar Martin, and A. Palacios. "Assessment of Different Spectral Indices in the Red-Near-Infrared Spectral Domain for Burned Land Discrimination." Remote Sensing of Environment 112 (2002): 2381-2396." (ESRI, 2018)