More info on spotting in wildfires

As mentioned in the introduction, spotting distances of up to
,2.0 km are commonly observed on crown fires in conifer
forests (Partners in Protection 2003 B; Beck and Simpson 2007;
Forest Fire Management Group 2007). A few observations of
spot fire distances of ,3.0 km have been made (USDA Forest
Service 1952; Fryer and Johnson 1988) and spotting distances
close to 5.0 km have been reported in the past in northern Idaho
(Jemison 1932) and central Wisconsin (Haines and Smith 1987).
Such a spot fire distance was also reported to have occurred
during the 2003 fire season in British Columbia, Canada (D. S.
Marek, British Columbia Wildfire Management Branch, pers.
comm., 2010). Furthermore, Stocks (1995) explored the possi-
bility that an ,7-km spot fire distance in north-central Ontario
resulted from an escaped prescribed fire as opposed to a human-
caused fire or a lightning-ignited holdover fire.

Brown and Davis (1973) claim that there are authenticated
cases in the USA of spot fires set up to 11 km ahead of the main
fire. Unfortunately, they give no specific details on the fuel
types, topography or weather conditions involved with such
occurrences. However, spotting distances of 6 to 10 km were
reported to have occurred in the northern Rocky Mountains of
the USA during the 1910 and 1934 fire seasons (Gisborne 1935;
Koch 1978). The circumstances associated with the spotting
distances of 16 to 19 km reported for the 1967 Sundance Fire in
northern Idaho, USA (Anderson 1968; Rothermel 1968; Finklin
1973), as described by Berlad and Lee (1968) and Lee (1972),
are undoubtedly beyond the predictive capacity of the mathe-
matical model as described here. Spotting between 15 and 20 km
was reported to have occurred in the radiata pine (Pinus radiata)
plantation fuel types associated with the 1983 Mount Muirhead
Fire in South Australia (Keeves and Douglas 1983; O'Connor and O"Connor 1993

from - https://www.researchgate.net/publication/267988468_A_mathematical_model_for_predicting_the_maximum_potential_spotting_distance_from_a_crown_fire