Search Results

You are looking at 1 - 10 of 2,775 items for :

  • Forest fires x
  • Refine by Access: All Content x
Clear All
Warren E. Heilman
,
Xindi Bian
,
Kenneth L. Clark
,
Nicholas S. Skowronski
,
John L. Hom
, and
Michael R. Gallagher

1. Introduction Wildland fires often occur in forested environments. Fire spread and smoke dispersion through these environments are affected by ambient and fire-induced atmospheric circulations, which, in turn, are influenced by the presence of forest vegetation ( Albini and Baughman 1979 ; Ryan 2002 ; Taylor et al. 2004 ; Kiefer et al. 2014 ; Seto et al. 2014 ; Heilman et al. 2015 ). The properties of atmospheric mean and turbulent circulations inside forest vegetation layers in the

Full access
Alec G. Stephenson
,
Benjamin A. Shaby
,
Brian J. Reich
, and
Andrew L. Sullivan

, to inform land-planning and life-safety management policies, and to issue warnings to the general public. In Australia, where wildfires are more commonly called bushfires, the fire danger rating systems of McArthur (1966 , 1967) are used. These systems combine weather and fuel information to calculate an index of fire danger that is used to define the fire danger rating. Of the two fire danger rating systems in use in Australia, we constrain our focus to the forest fire danger index (FFDI

Full access
Warren E. Heilman
,
Xindi Bian
,
Kenneth L. Clark
, and
Shiyuan Zhong

1. Introduction Atmospheric turbulence regimes in the vicinity of wildland fires, which often occur in forested environments, can affect fire behavior and the dispersion of smoke ( Clements et al. 2008 ; Mandel et al. 2009 ; Sun et al. 2009 ; Goodrick et al. 2013 ; Simpson et al. 2016 ). Fortunately, recent observational studies during wildland fire events have made great strides in improving our understanding of the evolution and properties of fire-induced atmospheric turbulence regimes

Full access
Warren E. Heilman
,
Tirtha Banerjee
,
Craig B. Clements
,
Kenneth L. Clark
,
Shiyuan Zhong
, and
Xindi Bian

disproportionate amount to the total vertical turbulent heat-flux fields within forest vegetation layers. Although studies of sweep–ejection dynamics in the lower ABL have been numerous over the last four decades, little is known about the sweep–ejection dynamics that occur in the highly perturbed environment surrounding wildland fires. Beer (1991) and Pimont et al. (2009) noted that coherent turbulent structures leading to turbulent heat- and momentum-flux sweep and ejection events within forest

Full access
Amir Shabbar
,
Walter Skinner
, and
Mike D. Flannigan

1. Introduction Wildland fire is a dominant disturbance regime in Canadian forests, particularly in the boreal forest region where fire is a process critical to the very existence of primary boreal species such as pine, spruce, and aspen and is responsible for shaping landscape diversity and influencing energy flows and biogeochemical cycling ( Stocks et al. 2002 ). Stocks et al. (1996) examined the spatial distribution of large fires in Canada during the 1980s when an average of almost 10

Full access
GEORGE C. JOY

humidity may be 29 per cent and the moisture content only 9 per cent. This sort ofvariation, when it occurs nenr the dnnger line of in- flammability, ns in this pnrticular cnse, is a yery ini- portnnt factor in predicting dangerous fire conditions. At the Priest River Experiment Station, therefore, moisture content is used directly as an index of inflam- mability. As the top layer of duff is the material which carries &e throu h the forest, it is the one which is chiefly concernef in predicting

Full access
Tess W. P. Jacobson
,
Richard Seager
,
A. Park Williams
, and
Naomi Henderson

indigenous people controlling fires locally and igniting fires for management of the land ( Anderson 2006 ; van Wagtendonk 2007 ). When European colonizers decimated the Native population, began logging forests and tilling grasslands, and brought livestock to graze, the vegetation and fire regime in the west were altered significantly. In the early twentieth century, the U.S. Forest Service (USFS) set out to completely suppress all fires on USFS land ( Marlon et al. 2012 ; van Wagtendonk 2007 ). This

Full access
Brian E. Potter
and
Daniel McEvoy

://doi.org/10.1016/j.foreco.2012.02.035 . 10.1016/j.foreco.2012.02.035 Fosberg , M. A. , 1978 : Weather in wildland fire management: The fire weather index. Proc. Conf. on Sierra Nevada Meteorology , Lake Tahoe, CA, Amer. Meteor. Soc. and USDA Forest Service, 1–4 . Hobbins , M. T. , A. Wood , D. J. McEvoy , J. L. Huntington , C. Morton , M. Anderson , and C. Hain , 2016 : The evaporative demand drought index. Part I: Linking drought evolution to variations in evaporative demand . J

Full access
Wesley G. Page
,
Natalie S. Wagenbrenner
,
Bret W. Butler
,
Jason M. Forthofer
, and
Chris Gibson

as good or bad following the recommendations of Cruz and Alexander (2013) . Specifically, based on an analysis of several fire spread model evaluation datasets for seven fuel-type groups, they determined that ±35% error of head fire rate of spread was a reasonable standard for fire behavior model adequacy ( Cruz and Alexander 2013 ). Rate-of-spread predictions that were within ±35% error were classified as good while all others were classified as bad. Random forests ( Breiman 2001 ) as

Open access
Tess W. P. Jacobson
,
Richard Seager
,
A. Park Williams
,
Isla R. Simpson
,
Karen A. McKinnon
, and
Haibo Liu

1. Introduction Over the last half century, the southwestern United States (herein referred to as “the Southwest United States” or “the Southwest”) experienced dramatic increases in forest fire activity. One crucial quantity for representing the influence of climate on fire activity in the western United States is vapor pressure deficit (VPD), a measure of atmospheric aridity that quantifies how far from saturated the atmosphere is at a given temperature and humidity, that is, the

Restricted access