BI < 40 (FL < 4 ft): Fires can generally be attacked at the head or flanks by persons using hand tools. Hand line should hold the fire.
BI = 40-80 (FL = 4-8 ft): Fires are too intense for direct attack on the head by persons using hand tools. Hand line cannot be relied on to hold fire. Equipment such as dozers, pumpers, and retardant aircraft can be effective.
BI = 80-110 (FL = 8-11 ft): Fires may present serious control problems – torching out, crowning, and spotting. Control efforts at the fire head will probably be ineffective.
BI > 110 (FL > 11 ft): Crowning, spotting, and major fire runs are probable. Control efforts at the head of the fire are ineffective.Burning Index is a function of the fuel model being used, the live and dead fuel loads, the live and dead fuel moistures, and the weather conditions. If the fuel types and loads are substantially different than those in the fuel model being used, there will be inaccuracies. It is also important to realize that these indices produced by the National Fire Danger Rating system are for the conditions modeled at 500-m resolution. In other words, the fuel model represents conditions over the entire 500-m pixel area, so indices such as BI are not meant to be used on a field-by-field basis. As an example, if the particular fuel in the area of concern (e.g., a particular field) differs from the assigned fuel model in that 500-m pixel, then the Oklahoma Fire Danger Model results for that pixel can be expected to be different than for the particular field in question (e.g., an open grassy area in a 500-m pixel that has been assigned a forest fuel model).