Meteorological Conditions Conducive to the Rapid Spread of the Deadly Wildfire in Eastern Attica, Greece

AbstractOn 23 July 2018, Attica, Greece, was impacted by a major wildfire that took place in a wildland–urban interface area and exhibited extreme fire behavior, characterized by a very high rate of spread. One-hundred civilian fatalities were registered, establishing this wildfire as the second-deadliest weather-related natural disaster in Greece, following the heat wave of July 1987. On the day of the deadly wildfire, a very strong westerly flow was blowing for more than 10 h over Attica. Wind gusts up to 30–34 m s−1 occurred over the mountainous areas of Attica, with 20–25 m s−1 in the city of Athens and surrounding suburban areas. This strong westerly flow interacted with the local topography and acted as downslope flow over the eastern part of Attica, with temperatures rising up to 39°C and relative humidity dropping to 19% prior to the onset of the wildfire. These weather elements are widely acknowledged as the major contributing factors to extreme fire behavior. WRF-SFIRE correctly predicted the spatiotemporal distribution of the fire spread and demonstrated its utility for fire spread warning purposes.

Download Full-text

Coupled Fire–Atmosphere Simulations of the Rocky River Fire Using WRF-SFIRE

Journal of Applied Meteorology and Climatology ◽

10.1175/jamc-d-15-0157.1 ◽

2016 ◽

Vol 55 (5) ◽

pp. 1151-1168 ◽

Cited By ~ 7

Author(s):

Mika Peace ◽

Trent Mattner ◽

Graham Mills ◽

Jeffrey Kepert ◽

Lachlan McCaw

Keyword(s):

Fire Behavior ◽

South Australia ◽

Simulation Models ◽

Fire Spread ◽

Fire Plume ◽

Spread Model ◽

Mesoscale Convective ◽

Rayleigh Benard ◽

Fire Spread Model ◽

Extreme Fire

AbstractThe coupled atmosphere–fire spread model “WRF-SFIRE” has been used to simulate a fire where extreme fire behavior was observed. Tall flames and a dense convective smoke column were features of the fire as it burned rapidly up the Rocky River gully on Kangaroo Island, South Australia. WRF-SFIRE simulations of the event show a number of interesting dynamical processes resulting from fire–atmosphere feedback, including the following: fire spread was sensitive to small changes in mean wind direction; fire perimeter was affected by wind convergence resulting from interactions between the fire, atmosphere, and local topography; and the fire plume mixed high-momentum air from above a strong subsidence inversion. At 1-min intervals, output from the simulations showed fire spread exhibiting fast and slow pulses. These pulses occurred coincident with the passage of mesoscale convective (Rayleigh–Bénard) cells in the planetary boundary layer. Simulations show that feedback between the fire and atmosphere may have contributed to the observed extreme fire behavior. The findings raise questions as to the appropriate information to include in meteorological forecasts for fires as well as future use of coupled and uncoupled fire simulation models in both operational and research settings.

Download Full-text

The 2013 Rim Fire: Implications for Predicting Extreme Fire Spread, Pyroconvection, and Smoke Emissions

Bulletin of the American Meteorological Society ◽

10.1175/bams-d-14-00060.1 ◽

2015 ◽

Vol 96 (2) ◽

pp. 229-247 ◽

Cited By ~ 50

Author(s):

David A. Peterson ◽

Edward J. Hyer ◽

James R. Campbell ◽

Michael D. Fromm ◽

Johnathan W. Hair ◽

...

Keyword(s):

Pacific Northwest ◽

Weather Prediction ◽

Regional Scale ◽

Fire Behavior ◽

Primary Source ◽

Fire Spread ◽

Detailed Examination ◽

Rim Fire ◽

Automated Forecasting ◽

Extreme Fire

Abstract The 2013 Rim Fire, which burned over 104,000 ha, was one of the most severe fire events in California’s history, in terms of its rapid growth, intensity, overall size, and persistent smoke plume. At least two large pyrocumulonimbus (pyroCb) events were observed, allowing smoke particles to extend through the upper troposphere over a large portion of the Pacific Northwest. However, the most extreme fire spread was observed on days without pyroCb activity or significant regional convection. A diverse archive of ground, airborne, and satellite data collected during the Rim Fire provides a unique opportunity to examine the conditions required for both extreme spread events and pyroCb development. Results highlight the importance of upper-level and nocturnal meteorology, as well as the limitations of traditional fire weather indices. The Rim Fire dataset also allows for a detailed examination of conflicting hypotheses surrounding the primary source of moisture during pyroCb development. All pyroCbs were associated with conditions very similar to those that produce dry thunderstorms. The current suite of automated forecasting applications predict only general trends in fire behavior, and specifically do not predict 1) extreme fire spread events and 2) injection of smoke to high altitudes. While these two exceptions are related, analysis of the Rim Fire shows that they are not predicted by the same set of conditions and variables. The combination of numerical weather prediction data and satellite observations exhibits great potential for improving automated regional-scale forecasts of fire behavior and smoke emissions.

Download Full-text

Examining fire behavior in mesquite - acacia shrublands

International Journal of Wildland Fire ◽

10.1071/wf03053 ◽

2005 ◽

Vol 14 (2) ◽

pp. 131 ◽

Cited By ~ 11

Author(s):

Tamara J. Streeks ◽

M. Keith Owens ◽

Steve G. Whisenant

Keyword(s):

Flame Temperature ◽

Fire Behavior ◽

Fire Spread ◽

Flame Length ◽

South Texas ◽

Fire Intensity ◽

Rate Of Spread ◽

Vegetation Shift ◽

Naturally Occurring ◽

Behavior Systems

The vegetation of South Texas has changed from mesquite savanna to mixed mesquite–acacia (Prosopis–Acacia) shrubland over the last 150 years. Fire reduction, due to lack of fine fuel and suppression of naturally occurring fires, is cited as one of the primary causes for this vegetation shift. Fire behavior, primarily rate of spread and fire intensity, is poorly understood in these communities, so fire prescriptions have not been developed. We evaluated two current fire behavior systems (BEHAVE and the CSIRO fire spread and fire danger calculator) and three models developed for shrublands to determine how well they predicted rate of spread and flame length during three summer fires within mesquite–acacia shrublands. We also used geostatistical analyses to examine the spatial pattern of net heat, flame temperature and fuel characteristics. The CSIRO forest model under-predicted the rate of fire spread by an average of 5.43 m min−1 and over-predicted flame lengths by 0.2 m while the BEHAVE brush model under-predicted rate of spread by an average of 6.57 m min−1 and flame lengths by an average of 0.33 m. The three shrubland models did not consistently predict the rate of spread in these plant communities. Net heat and flame temperature were related to the amount of 10-h fuel on the site, but were not related to the cover of grasses, forbs, shrubs, or apparent continuity of fine fuel. Fuel loads were typical of South Texas shrublands, in that they were uneven and spatially inconsistent, which resulted in an unpredictable fire pattern.

Download Full-text

Georeferencing Oblique Aerial Wildfire Photographs: An Untapped Source of Fire Behaviour Data

Fire ◽

10.3390/fire4040081 ◽

2021 ◽

Vol 4 (4) ◽

pp. 81

Author(s):

Henry Hart ◽

Daniel D. B. Perrakis ◽

Stephen W. Taylor ◽

Christopher Bone ◽

Claudio Bozzini

Keyword(s):

Fire Behavior ◽

Fire Spread ◽

Behavior Prediction ◽

Empirical Relationships ◽

Rate Of Spread ◽

Front Position ◽

Fire Front ◽

Initial Work ◽

The Mean ◽

Behaviour Data

In this study, we investigate a novel application of the photogrammetric monoplotting technique for assessing wildfires. We demonstrate the use of the software program WSL Monoplotting Tool (MPT) to georeference operational oblique aerial wildfire photographs taken during airtanker response in the early stages of fire growth. We located the position of the fire front in georeferenced pairs of photos from five fires taken 31–118 min apart, and calculated the head fire spread distance and head fire rate of spread (HROS). Our example photos were taken 0.7 to 4.7 km from fire fronts, with camera angles of incidence from −19 to −50° to image centre. Using high quality images with detailed landscape features, it is possible to identify fire front positions with high precision; in our example data, the mean 3D error was 0.533 m and the maximum 3D error for individual fire runs was less than 3 m. This resulted in a maximum HROS error due to monoplotting of only ~0.5%. We then compared HROS estimates with predictions from the Canadian Fire Behavior Prediction System, with differences mainly attributed to model error or uncertainty in weather and fuel inputs. This method can be used to obtain observations to validate fire spread models or create new empirical relationships where databases of such wildfire photos exist. Our initial work suggests that monophotogrammetry can provide reproducible estimates of fire front position, spread distance and rate of spread with high accuracy, and could potentially be used to characterize other fire features such as flame and smoke plume dimensions and spotting.

Download Full-text

Behavior of experimental grass fires vs. predictions based on Rothermel's fire model

Canadian Journal of Forest Research ◽

10.1139/x77-045 ◽

1977 ◽

Vol 7 (2) ◽

pp. 357-367 ◽

Cited By ~ 28

Author(s):

Richard J. Sneeuwjagt ◽

William H. Frandsen

Keyword(s):

Combustion Zone ◽

Fire Behavior ◽

Fire Spread ◽

Flame Length ◽

Fuel Load ◽

Physical Parameters ◽

Rate Of Spread ◽

Least Squares Fit ◽

Zone Depth ◽

Positive Agreement

Fire behavior observations with rates of spread up to 20 m/min (66 ft/min) have been recorded on 40 prescribed grass fires in central Washington and northern California. Physical parameters were also recorded describing the grass fuel array (fuel load, moisture content (≤ 15%), etc.), along with the wind speed (up to 8 km/h) and slope (near zero). These data were sufficient to allow a prediction of the fire spread rate, combustion zone depth, and flame length using the Rothermel fire spread model.A least squares fit of the observed versus the predicted results shows that positive agreement (slope = 1, intercept = 0) is supported for rate of spread. Flame length shows positive agreement for the intercept but not for slope. Combustion zone depth does not show positive agreement for either intercept or slope. The authors attribute the lack of positive agreement to less accurate measurements (ocular estimates) of the flame length and combustion zone depth.

Download Full-text

Testing the Effect of Fuel Consumption on Fire Spread Rate

International Journal of Wildland Fire ◽

10.1071/wf9950143 ◽

1995 ◽

Vol 5 (3) ◽

pp. 143 ◽

Cited By ~ 9

Author(s):

RS McAlpine

Keyword(s):

Fuel Consumption ◽

Fire Behavior ◽

Fire Spread ◽

Data Sets ◽

Behavior Prediction ◽

Spread Rate ◽

Data Set ◽

Weak Relationship ◽

Rate Of Spread ◽

Fire Front

It has been theorized that the amount of fuel involved in a fire front can influence the rate of spread of the fire. Three data sets are examined in an attempt to prove this relationship. The first, a Canadian Forest Service database of over 400 experimental, wild, and prescribed fires showed a weak relationship in some fuel complexes. The second, a series of field experimental fires conducted to isolate the relationship, showed a small effect. The final data set, from a series of 47 small plots (3m x 3m) burned with a variety of fuel loadings, also show a weak relationship. While a relationship was shown to exist, it is debatable whether it should be included in a fire behavior prediction system. Inherent errors associated with predicting fuel consumption can be compounded, causing additional, more critical, errors with the derived fire spread rate.

Download Full-text

An effective wind speed for models of fire spread

International Journal of Wildland Fire ◽

10.1071/wf02031 ◽

2002 ◽

Vol 11 (2) ◽

pp. 153 ◽

Cited By ~ 35

Author(s):

Ralph M. Nelson, Jr.

Keyword(s):

Wind Speed ◽

Slope Angle ◽

Fire Behavior ◽

Fire Spread ◽

Spread Rate ◽

Ambient Wind ◽

Rate Of Spread ◽

Spread Model ◽

The Difference ◽

Fire Spread Model

In previous descriptions of wind-slope interaction and the spread rate of wildland fires it is assumed that the separate effects of wind and slope are independent and additive and that corrections for these effects may be applied to spread rates computed from existing rate of spread models. A different approach is explored in the present paper in which the upslope component of the fire's buoyant velocity is used with the speed and direction of the ambient wind to produce effective values of wind speed and direction that determine the rate of spread vector. Thus the effective wind speed can replace the ambient wind speed in any suitable fire spread model and provide a description of the combined effects on the fire behavior. The difference between current and threshold values of the effective wind speed also can be used to determine whether fire will spread in a given fuel type. The model is tested with data from experiments reported by Weise (1993) in which fire spread was in response to variation in both wind speed and slope angle. The Weise spread rate data were satisfactorily correlated using dimensional methods and the observed spread rate was reasonably well predicted with an existing rate of spread model. Directional aspects of the model were not tested because the Weise (1993) study did not include winds with a cross-slope component.

Download Full-text

Simulated Fire Behavior and Fine-Scale Forest Structure Following Conifer Removal in Aspen-Conifer Forests in the Lake Tahoe Basin, USA

Fire ◽

10.3390/fire3030051 ◽

2020 ◽

Vol 3 (3) ◽

pp. 51

Author(s):

Justin P. Ziegler ◽

Chad M. Hoffman ◽

Brandon M. Collins ◽

Jonathan W. Long ◽

Christa M. Dagley ◽

...

Keyword(s):

Forest Structure ◽

Fire Suppression ◽

Fire Hazard ◽

Fire Behavior ◽

Fire Spread ◽

The United States ◽

Quaking Aspen ◽

Lake Tahoe Basin ◽

Rate Of Spread ◽

Growing Conditions

Quaking aspen is found in western forests of the United States and is currently at risk of loss due to conifer competition at within-stand scales. Wildfires in these forests are impactful owing to conifer infilling during prolonged fire suppression post-Euro-American settlement. Here, restoration cuttings seek to impact wildfire behavior and aspen growing conditions. In this study, we explored how actual and hypothetical cuttings with a range of conifer removal intensity altered surface fuel and overstory structure at stand and fine scales. We then simulated wildfires, examining fire behavior and effects on post-fire forest structures around aspen trees. We found that conifer removal constrained by lower upper diameter limits (<56 cm) had marginal effects on surface fuel and overstory structure, likely failing to enhance resource conditions sufficiently to sustain aspen. Increasing the diameter limit also led to a higher likelihood of fire spread and a higher rate of spread, owing to greater within-canopy wind speed, though crown fire activity decreased. Our simulations suggest heavier treatments could facilitate reintroduction of fire while also dampening the effects of wildfires on forest structure. Cutting specifications that relax diameter limits and remove a substantial portion of conifer overstory could better promote aspen restoration and mitigate fire hazard.

Download Full-text

COMPORTAMENTO DO FOGO, EM CONDIÇÕES DE LABORATÓRIO, EM COMBUSTÍVEIS PROVENIENTES DE UM POVOAMENTO DE Pinus elliottii L.

FLORESTA ◽

10.5380/rf.v34i2.2383 ◽

2004 ◽

Vol 34 (2) ◽

Author(s):

Luciana Valle De Loro ◽

Nelson Akira Hiramatsu

Keyword(s):

Laboratory Test ◽

Fire Behavior ◽

Pinus Elliottii ◽

Fire Spread ◽

Flame Length ◽

Flame Height ◽

Fire Intensity ◽

Forest Fuels ◽

Rate Of Spread ◽

Fire Laboratory

De um povoamento de Pinus elliottii localizado na Fazenda Canguiri-UFPR, foram coletadas seis amostras de material combustível superficial. Este material foi separado em classes, pesado e levado para o laboratório. Efetuou-se a queima da classe acículas num leito de areia no laboratorio, em seis queimas, sendo cada queima com acículas proveniente de cada uma das amostras coletadas. Foram medidas a altura, o comprimento e a velocidade de propagação do fogo. Aplicou-se para cada queima cerca de 746 g de acículas, equivalente a 0,678 Kg/m2, com uma espessura média de 3 cm. Foram obtidos como dados médios: velocidade de propagação de 0,00423 m/s, comprimento da chama de 35,22 cm e altura de 38,79 cm, resultando numa intensidade do fogo igual a 57,07 kW/m. O resíduo médio ficou na ordem de 40,3 %. FIRE BEHAVIOR, IN LABORATORY CONDITIONS, OF FOREST FUELS FROM A Pinus elliottii L. STAND Abstract Pinus elliottii needles from a stand located at Fazenda Canguiri-UFPR were collected to run a laboratory test on fire behavior. The fuel from six samples was separated in classes, weight, and taken to the Federal University of Paraná Forest Fire Laboratory. The pine needles were burned in a sand bed. About 746.0g of each one of the six samples, equivalent to 0.678kg.m-2 and 3cm depth, were used in each fire run. Flame height and length, and rate of spread were measured. The average values obtained were: fire spread, 0,00423 m.s-1, flame length, 35,22cm, and flame height, 38,79cm. Fire intensity was of 57,07 kW.m-1 and residual fuel content about 40,3%.

Download Full-text

Fine-Scale Fire Spread in Pine Straw

Fire ◽

10.3390/fire4040069 ◽

2021 ◽

Vol 4 (4) ◽

pp. 69

Author(s):

Daryn Sagel ◽

Kevin Speer ◽

Scott Pokswinski ◽

Bryan Quaife

Keyword(s):

Fire Spread ◽

Small Scale ◽

Natural Setting ◽

Fine Scale ◽

Prescribed Burn ◽

Fire Dynamics ◽

Rate Of Spread ◽

Scale Models ◽

Fire Front ◽

Visible Images

Most wildland and prescribed fire spread occurs through ground fuels, and the rate of spread (RoS) in such environments is often summarized with empirical models that assume uniform environmental conditions and produce a unique RoS. On the other hand, representing the effects of local, small-scale variations of fuel and wind experienced in the field is challenging and, for landscape-scale models, impractical. Moreover, the level of uncertainty associated with characterizing RoS and flame dynamics in the presence of turbulent flow demonstrates the need for further understanding of fire dynamics at small scales in realistic settings. This work describes adapted computer vision techniques used to form fine-scale measurements of the spatially and temporally varying RoS in a natural setting. These algorithms are applied to infrared and visible images of a small-scale prescribed burn of a quasi-homogeneous pine needle bed under stationary wind conditions. A large number of distinct fire front displacements are then used statistically to analyze the fire spread. We find that the fine-scale forward RoS is characterized by an exponential distribution, suggesting a model for fire spread as a random process at this scale.

Download Full-text