What are the values of KBDI (Keetch-Byram Drought Index) in each class for interpretation of drought event?

The Keetch-Byram drought index (KBDI) was developed to estimate flammability in forest and wild land areas of the USA (Keetch andByram1968).Because it uses daily precipitation and dailymaximum temperature, KBDI has the potential to describe cumulative moisture deficiency in upper soil layers (Keetch and Byram 1968). KBDI has primarily been used for planning fire management operations (Dolling et al. 2005), and it is still considered a robust indicator of wildfire probability (Arpaci et al.2013).Other studies have appliedKBDI for agricultural drought approximation (Brolley et al. 2007;Liuetal. 2010;Petrosetal. 2011; Garcia-Prats et al. 2015;Taufiketal. 2015). Since KBDI includes maximum temperature and precipitation changes, it follows growing season patterns in KBDI should have explanatory power over crop yield variations.

It ranges from 0 to 800 with the value of 800 having no moisture (indicating extreme drought) in the upper layers of the soil and 0 indicating saturated soil. The Keetch-Byram Drought Index is a surrogate for the amount of moisture in the upper layers of the soil (Keetch and Byram, 1988), and according to this point it has five class. Therefor they are five classes, namely 0-150, 150-300, 300-500, 500-700, and 700-800. For obtaining more details refer to Janis et al., 2002. For more details you can read KBDI Drought paper.

The KBDI's values between 0-150: Upper soil and surface litter are wet. Fire potential is minimal.

The KBDI's values between 150-300: Upper soil and surface litter are moist and don't contribute to fire intensity. Fire behavior is predictable.

The KBDI's values between 300-500: Upper soil and surface litter are dry and may contribute to fire intensity. Fire consumes most surface litter along with a significant loss in organic soil material. Although escaped fire is difficult to control, fire behaviour is somewhat predictable.

The KBDI's values between 500-700: Upper soil and surface litter are very dry. Above 600 is associated with severe drought. Above 600, fire suppression is a significant undertaking.

The KBDI's values between 700-800: Upper soil and surface litter are extremely dry. Fire behavior is unpredictable with crowning and downwind spotting. Associated with extreme drought and increased wildfire occurrence.

The Keetch-Byram Drought Index (KBDI) is an index for measuring drought in the context of wildfires because the index is a proxy for the moisture in vegetation and other fuels (Keetch and Byram, 1988).