Percent Fire Severity (PFS) is three products merged into one. It is a combination product of what was previously (LF 2014 and earlier) known as Percent Mixed, Low, and Replacement Severity. Low severity is defined as less than 25 percent average top-kill within a typical fire perimeter for a given vegetation type. Mixed severity is defined as between 25 and 75 percent average top-kill within a typical fire perimeter for a given vegetation type. Replacement severity is defined as greater than 75 percent average top-kill within a typical fire perimeter for a given vegetation type. To learn more about PFS go to https://landfire.gov/fire-regime/pfs.
At the release of LF 2016 Remap Fire Regime Groups (FRG_NEW), Percent of Low-severity Fire (PRC_SURFAC), Percent of Mixed-severity Fire (PRC_MIXED), Percent of Replacement-severity Fire (PRC_REPLAC), and Fire Return Interval (FRI_ALLFIR) were included as attributes in the Biophysical Settings (BPS) product. Then in 2024 these products became stand-alone products once again. With the 3 Percent Severity products merged into a single product called Percent Fire Severity (PFS). These products can now be found in both places, as attributes of BPS and as their own individual products.