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Type: Magazine Article
Author(s): Miguel G. Cruz; Martin E. Alexander
Publication Date: 2021

[From the Introduction] In the October-December 2019 issue of WILDFIRE, we described a recently developed rule of thumb for estimating a wildfire’s forward spread rate when burning conditions are severe, namely when wind speeds are high and fuels are critically dry, and the time available to prepare a more exacting prediction is limited (Alexander and Cruz 2019). Based on the analysis of three distinct datasets comprising 118 high-intensity wildfire runs from around the world in forests (conifer- and eucalyptdominated) and shrublands, rate of spread was considered to be roughly 10% of the prevailing 10-m (33-ft) open wind speed, independent of the unit system used (Cruz and Alexander 2019). For example, given an open wind speed of 25 km/h (16 mi/h), the estimated wildfire spread rate during severe burning conditions would be approximately 2.5 km/h (1.6 mi/h). Here we present a summary of an evaluation study that analyzed the predictive accuracy of the 10% rule of thumb against two large, independent wildfire datasets. For further details on the study, see Cruz et al. (2020, linked below).

Online Links
Citation: Cruz, Miguel G.; Alexander, Martin E. 2021. Evaluating the 10% wind speed rule of thumb for estimating a wildfire’s forward spread rate. Wildfire Magazine 30(1):48-50.

Cataloging Information

Alaska    California    Eastern    Great Basin    Hawaii    Northern Rockies    Northwest    Rocky Mountain    Southern    Southwest    International    National
Partner Sites:
  • Australia
  • Canada
  • conifer forests
  • critical fire weather
  • dead fuel moisture content
  • dead fuels
  • dry eucalypt forests
  • fine fuels
  • fire prediction
  • fire propagation
  • fire spread
  • fuel moisture
  • fuel type
  • high intensity fires
  • model error
  • North America
  • ROS - rate of spread
  • temperate shrublands
  • wildfires
  • wind speed
  • winds
Record Last Modified:
Record Maintained By: FRAMES Staff (
FRAMES Record Number: 66121