Fourth Symposium on Fire and Forest Meteorology

Tuesday, 13 November 2001
Florida wildfire initiation and environmental conditions during 1998
Arlene G. Laing, University of South Florida, Tampa, FL; and C. H. Paxton, S. L. Goodrick, D. Sharp, and P. F. Blottman
Poster PDF (221.2 kB)
During late spring and early summer 1998, Florida experienced an unprecedented outbreak of over 2,300 fires that covered nearly a half million acres and caused 500 million dollars of damage. Although most of Florida had record rainfall during the previous winter, dry conditions during the spring left those same areas vulnerably dry. Interestingly, while these dry conditions prevailed throughout the state, fire initiation and acreage were quite variable in space and time. Climate indices like the Keetch Bryam were not as useful for determining daily variability in fire acreage or ignition.

Considerable contrasts are evident in the atmosphere between a day in which fires were suppressed and a day in which a dramatic expansion in the areal extent of fires occurred. The period of suppression was associated with passage of a significant trough and intrusion of subsident air over much of Florida. In comparison, the fire outbreak was characterized by adequate instability and moisture for convection, a light surface flows opposing sea breezes, and light winds aloft. This generated stationary convection and considerable lightning leading to initiation of fires particularly outside rain areas. Lightning-initiated fires accounted for 79% of the acres burnts. This study examines the overall trends in flash density, frequency of fire initiation, low-level moisture, mesoscale circulation patterns. The influence of fuel-type and antecedent precipitation on the lag between flash and full-blown combustion are also considered.

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