scieee Science in your language
[en] (orig)
1. Introduction
Australia's 2019/2020 “Black Summer” fire season was exceptional in terms of the number of fires, burned
area, and fire severity (Baldwin & Ross,2020; Deb etal.,2020; Hughes etal.,2020). The fires followed an un-
precedented drought; 2019 was the driest year on record (Hughes etal.,2020; van Oldenborgh etal.,2021).
Throughout the continent, the fires caused direct damages to humans and ecosystems, including at least 33
directly fire-related deaths, 3,100 homes lost, an area of at least 24 million hectares burned—the size of the
United Kingdom—, and never before seen air pollution levels in major cities (Davey & Sarre,2020; Hughes
etal.,2020; Royal Commission into National Natural Disaster Arrangements,2020; Vardoulakis etal.,2020).
The wildfires led to the formation of a record number of pyrocumulonimbus clouds that reached the lower
stratosphere over southeastern Australia (Kablick III etal.,2020).
Wildfires cause hydrometeorological and geomorphic changes that can heighten the susceptibility of
burned areas to other hazards; for example, raised soil water repellency after a fire can lead to increased
runoff (Shakesby & Doerr,2006). This was the case with the 2019/2020 fires: following an extreme drought,
the fires were the second step in an entire cascade of adverse processes (Figure1). Next, rainfall in Febru-
ary 2020 triggered increased surface runoff and eroded ash and soil. Entrained ash, plant, and soil depos-
its enhanced sediment concentration in rivers, damaging infrastructure and compromising water quality
Abstract Following an unprecedented drought, Australia's 2019/2020 “Black Summer” fire season
caused severe damage, gravely impacting both humans and ecosystems, and increasing susceptibility to
other hazards. Heavy precipitation in early 2020 led to flooding and runoff that entrained ash and soil
in burned areas, increasing sediment concentration in rivers, and reducing water quality. We exemplify
this hazard cascade in a catchment in New South Wales by mapping burn severity, flood, and rainfall
recurrence; estimating changes in soil erosion; and comparing them with river turbidity data. We show
that following the extreme drought and wildfires, even moderate rain and floods led to undue increases in
soil erosion and reductions in water quality. While natural risk analysis and planning commonly focuses
on a single hazard, we emphasize the need to consider the entire hazard cascade, and highlight the
impacts of ongoing climate change beyond its direct effect on wildfires.
Plain Language Summary In 2019/2020, a chain of natural hazards impacted Australia's
East Coast. Following the severest drought since weather records began, record-breaking wildfires known
as the “Black Summer” ravaged the region for months. In early 2020, the rainfall that extinguished the
last of these fires caused further damage, as the burned soils repelled much of the rain. Water took the
exposed soil and charred vegetation with it on its way to the rivers, flooding streets and polluting drinking
water. We show an example of this cascade of hazards in a single river catchment. We found that after
the wildfires, even moderate rainfall caused floods, increased soil erosion, and reduced water quality
drastically. Natural risk analyses mostly focus on single types of events in isolation. However, this hazard
cascade shows that, especially in the face of ongoing climate change, scientists and decision makers need
to consider events not just by themselves, but connected with each other.
KEMTER ET AL.
© 2021. The Authors.
This is an open access article under
the terms of the Creative Commons
Attribution License, which permits use,
distribution and reproduction in any
medium, provided the original work is
properly cited.
Cascading Hazards in the Aftermath of Australia's
2019/2020 Black Summer Wildfires
M. Kemter1,2,3 , M. Fischer1, L. V. Luna1,2 , E. Schönfeldt4 , J. Vogel1,5 , A. Banerjee1,2,
O. Korup1 , and K. Thonicke2
1Institute of Environmental Science and Geography, University of Potsdam, Potsdam, Germany, 2Potsdam Institute
for Climate Impact Research, Potsdam, Germany, 3Helmholtz Centre Potsdam, GFZ German Research Centre for
Geosciences, Potsdam, Germany, 4Institute of Geosciences, University of Potsdam, Potsdam, Germany, 5Institute of
Ecology, Technical University of Berlin, Berlin, Germany
Key Points:
• Australia's unprecedented wildfire
season 2019/2020 was part of a
complex hazard cascade of partly
extreme and partly moderate events
• We study the complete hazard
cascade of drought, fire, rain, flood,
and soil erosion in the Manning
River catchment, New South Wales
• We show that hazard cascades can
amplify the impacts of moderate
events, which requires renewed
consideration in risk management
Supporting Information:
Supporting Information may be found
in the online version of this article.
Correspondence to:
M. Kemter,
k[email protected]
Citation:
Kemter, M., Fischer, M., Luna, L. V.,
Schönfeldt, E., Vogel, J., Banerjee, A.,
et al. (2021). Cascading hazards in the
aftermath of Australia's 2019/2020
Black Summer wildfires. Earth's
Future, 9, e2020EF001884. https://doi.
org/10.1029/2020EF001884
Received 30 OCT 2020
Accepted 21 JAN 2021
10.1029/2020EF001884
Special Section:
Fire in the Earth System
COMMENTARY
1 of 7
Earth’s Future
(Alexandra & Finlayson,2020). In some cases, the ash-laden water con-
taminated water bodies such as the Lake Burragorang reservoir, Sydney's
main drinking water supply (FigureS1).
Extreme impacts, like those observed in Australia in early 2020, are often
caused by a combination of several drivers (Figure1). Their linkage can
lead to a so-called cascading event characterized by an initial impact that
triggers other, partly unexpected, effects of potentially destructive magni-
tudes (Pescaroli & Alexander,2015). However, the underlying drivers are
mostly studied separately and without considering their potential inter-
actions (AghaKouchak etal.,2018; Zscheischler etal.,2018). Appraisals
of flood risk in Australia, for example, may underestimate the actual risk,
if neglecting the impacts of an antecedent fire in the upstream catch-
ment. When extreme impacts are combined, their effect can be greater
than the sum of their parts, making a holistic approach crucial to analyz-
ing event sequences (AghaKouchak etal.,2018; Gill & Malamud,2016;
Hegerl etal.,2011; Zscheischler, Martius, etal.,2020). The analysis of
cascading events remains challenging because completely documented
cascades are scarce, suitable indices and methods for their quantification
are limited, and bulk uncertainties are often much higher than for sin-
gle events (Kappes etal.,2012; Schauwecker etal.,2019; Zscheischler,
Martius, etal.,2020). Here, we illustrate the stages of a hazard cascade in a catchment in New South Wales
(NSW), Australia (Figure2a). We argue that considering the hazards separately may lead to serious misesti-
mates of magnitudes, intensities, and durations of the processes involved, all of which may reverberate on
hazard and risk appraisals.
KEMTER ET AL.
10.1029/2020EF001884
2 of 7
Figure 1. Australia's 2019/2020 hazard cascade. Drought increased the
likelihood of wildfires, which burned vegetation and raised the likelihood
of increased surface runoff, soil erosion and hillslope failures. When
heavy rain fell in early 2020, runoff from burned areas led to flooding and
entrained ash, soil, and organic matter, increasing sediment concentrations
in rivers and negatively impacting water quality.
Figure 2. Study area. (a) The Manning River catchment is located 250km north of Sydney in one of the steepest
regions of New South Wales, Australia. (b) Fires affected the tributaries of the Manning River differently, with the
highest burn severities occurring in the Nowendoc catchment. (c) Gridded rainfall data for February 9th, 2020,
show increasing rainfall totals toward the coast. 1-Barnard River (Mackay), 2-Nowendoc River (Rock's Crossing),
3-Gloucester River (Doon Ayre), 4-Manning River (Killawarra). (d) Turbidity in brown and discharge in blue for
Manning River and its tributaries between February 1st and 22nd.
Earth’s Future
During 2019/2020, the Manning River catchment was affected by drought, fires, heavy rainfall, and high
sediment fluxes. Three of its tributaries experienced different degrees of burn severity (Figure2b) and
rainfall amounts (Figure2c), allowing us to compare the postfire impacts on streamflow and soil erosion
(Figure2d). By moving through the sequence of hazards, we explore how certain events triggered and in-
fluenced each other, changing their susceptibility as the event chain developed and its effects propagated
throughout the catchment.
2. Cascade Onset: Drought and Heat
2019 was the driest year on record in Australia (van Oldenborgh etal.,2021), with the lowest rainfall on
record from July to December in many parts of southeastern Australia (Nolan etal.,2020; data accessible
from http://www.bom.gov.au/climate/history/rainfall/). Neutral El Niño-Southern Oscillation conditions
and a positive Indian Ocean dipole were the main causes for the drought (King etal.,2020; van Oldenborgh
etal.,2021). In summer 2019, this event was accompanied by the highest mean maximum temperatures
since recording began in 1910, with the highest anomalies in December 2019 surpassing those of the “An-
gry Summer” of 2012/2013 (van Oldenborgh etal.,2021). This extraordinary drought was a key driver of
the wildfires, whereas the role of fuel accumulation due to fire suppression is still disputed (Bradstock
etal.,2020).
Based on gridded rainfall data (Jones etal.,2009, see supplements) we find that 2019 was the driest year in
the Manning River catchment since at least 1970 with a catchment average of only 440mm of rainfall, or
42% of the average annual rainfall of 1,040mm from 1970 to 2018. In December 2019, the river ran com-
pletely dry at Killawarra (Figure2d) for the first time on record (since 1945), where it has a daily average
streamflow of 55m³/s.
3. Initial Impact: Extreme Wildfire
Wildfires are a frequent natural hazard in Australia and have caused substantial economic and environ-
mental impacts in the past. Yet the 2019/2020 fires were exceptional in scale, and likely linked to anoma-
lous weather conditions driven by climate change (Bowman etal.,2020; Deb etal.,2020; van Oldenborgh
etal.,2021). They burned the largest continental fraction of any forest biome in at least 2decades (Boer
etal.,2020). Insurance claims from these fires totaled $2.34 billion AUD, making up 44% of all natural
disaster claims for the entire fire season (Whelan,2020). In comparison, wildfires accounted for 12% of nor-
malized insurance losses from natural hazards between 1966 and 2017 (McAneney etal.,2019). The total
loss also far exceeds that incurred by the 2009 “Black Saturday” fires, when insurance claims totaled $1.2
billion AUD (Victorian Bushfires Royal Commission, 2010). In NSW the fires caused the largest area burned
and highest property loss ever recorded (Hughes etal.,2020).
The 2019/2020 fires also had detrimental health effects. Most prominently, smoke-related air pollution
had an unprecedented burden on public health, with 417 total pollution-related excess deaths in eastern
Australia (Queensland, NSW, Australian Capital Territory, Victoria) of which 219 were recorded in NSW
(Borchers Arriagada etal.,2020). Smoke-related hospital admissions for cardiovascular and respiratory con-
ditions totaled 3,151, with 1,627 cases in NSW (Borchers Arriagada etal.,2020).
To assess the overall scope of burning in the Manning River catchment, we classified burn severity by
calculating the differential Normalized Burned Ratio (dNBR) from pre and postfire satellite imagery from
February 2019 and January 2020 respectively (Figure2b) (Key and Benson,2002, 2006); methods are
described in the supplements (Alleaume etal.,2005; Barrett,2006; French etal.,2008; Kinnell,2010;
Lentile etal.,2006; Soverel etal.,2010; Walz etal.,2007). While dNBR-derived burn severity levels solely
define burn-induced magnitude of radiometric change, Chafer(2008) conducted field studies in NSW to
provide a calibration to fire effects on vegetation community strata observed on the ground. They report-
ed that low severities signify burned grass and herbs; moderate severities imply consumed shrubs; high
severities indicate scorching of the lower canopy; and very high severities denote the consumption of
stems with diameters <10mm (Chafer,2008). We found that wildfires in the Manning River catchment,
KEMTER ET AL.
10.1029/2020EF001884
3 of 7
Earth’s Future
which occurred from mid-November to mid-December 2019 (Data.NWS NPWS, https://data.nsw.gov.
au/data/dataset/fire-history-wildfires-and-prescribed-burns-1e8b6), burned (dNBR>0.1) a total area of
4,765km2 or some 72% of the catchment (Figure2b). Moderate to high burn severities (dNBR>0.27)
mostly occurred in the Nowendoc tributary, where 57% (463km2) of the catchment area burned with this
intensity at least (TableS1).
4. Subsequent Effects: Floods, Soil Erosion, and Water Quality
Heavy rainfall eventually extinguished fires throughout NSW in February 2020. The rain replen-
ished depleted water reservoirs, but also led to the next hazard in the cascade. The resulting runoff
flooded parts of Sydney and other cities in NSW, caused mass movements which disrupted infra-
structure, and washed soil, ash, and debris into water bodies (FigureS1). Insurance claims of $896
million AUD were lodged in response to the rainstorms and associated floods (Insurance Council of
Australia,2020).
According to gridded rainfall data between 1970 and 2018 (see supplements), the Manning river catchment
averaged 78mm of rainfall on February 9th alone (Figure2c), which is about 58% of an average February
rainfall total in 1 day. On the scale of the entire catchment, such rainfall totals occur once in 5.6
17.3
2.4
years on average (TablesS2–S3). Rainfall was most intense in the southern part of the catchment (Fig-
ureS2), where two rain gauges measured their second highest values in records of at least 43years (see
supplements).
Although parts of the Manning River catchment witnessed heavy rainfall in February 2020, the resulting
floods, which we define here as the peak streamflow following the February 9th rainfall event, were only
minor. The return periods of the February 9th floods range from 1.8
0.6
0.3
years (Nowendoc catchment) to
4.7
9.8
1.7
years (Gloucester catchment), and are thus lower than those of the preceding rainfall (TablesS3–
S4). We hypothesize that low soil moisture in the catchment following the drought led to decreased stream-
flow (Sharma etal.,2018; Wasko etal.,2019). The hydrographs (Figure2d) show no signs of extensive
surface runoff, which would form a narrow sharp spike minutes to a few hours before the main flood peak
(Shakesby & Doerr,2006).
Water quality was drastically affected by this flood. In the Manning, Barnard and Nowendoc Rivers, tur-
bidity data logged in February 2020 show sharp peaks with no precedence in the 5–7years on record (Fig-
ure2d). In some cases, the turbidity exceeded the sensor measurement scale. The uncalibrated turbidity
values only allow a relative comparison of sediment loads in the tributaries. In the 6 years of shared record
prior to the 2019 fire season, synchronous turbidity peaks for the Gloucester and Nowendoc River were of
almost equal magnitude (see supplements). In the more severely burned Nowendoc catchment the mag-
nitude of the turbidity peak associated with the February 2020 flood was six times higher than in the less
severely burned Gloucester catchment.
We apply the RUSLE model (Kinnel,2010; Renard etal.,1991) to estimate first order the pre and postfire
soil erosion rates within the Manning River catchment based on rainfall erosivity, soil erodibility, steep-
ness, land cover and management, using input parameters from preexisting datasets (Yang etal.,2015,
2018) (see supplements). The dNBR burn severity is included by adjusting the postfire land cover-factor
accordingly (Blake etal.,2020; Larsen & MacDonald,2007) based on satellite data from February 2019
and 2020. The estimated postfire soil erosion rates range from 11-27t h−1y−1 (TableS1), reflecting an
increase of over 200%. The absolute values and relative changes are consistent with field measurements
from severely burned catchments in NSW (Atkinson,2012; Blake etal.,2020; Shakesby & Doerr,2006).
The increases in estimated soil erosion in the three tributaries range from 88% in the Gloucester catchment
to 358% in the Nowendoc catchment (FigureS3 and TableS1). The difference in the increase of erosion
rates between these two tributaries is consistent with the respective increase in turbidity values, and likely
linked to commensurate differences in burn severity.
KEMTER ET AL.
10.1029/2020EF001884
4 of 7
Earth’s Future
5. Conclusions and Outlook
The 2019/2020 hazard cascade observed in the Manning River catchment in southeast Australia highlights
how the impact of ongoing climate change on wildfires affects the likelihood and magnitude of adverse
consequences from other hazards that are in parts physically linked to each other. We show that following
extreme drought and wildfires, moderate rainfall and flood events were sufficient to increase estimated soil
erosion and reduce water quality far beyond expected levels in the absence of fires. These amplifying effects
of individual impacts within hazard cascades are still insufficiently considered in risk analysis. It is crucial
to fill this knowledge gap in hazard and risk appraisals, as moderate processes in hazard cascades can incur
much more damage than when they occur on their own.
Climate change is projected to increase the frequency of compounding extreme warm and dry periods in
Australia and beyond (Kharin & Zwiers,2005; Zscheischler etal.,2017), which could lead to further event
cascades like the one in 2019/2020 (Zscheischler, van den Hurk, etal.,2020). Indeed, in 2020, following Aus-
tralia's “Black Summer,” the western United States experienced its most-extensive fire season in 70years,
while extensive fires burned across Siberia (Irannezhad etal.,2020; Pickrell & Pennisi, 2020). So far, how-
ever, we can draw on only few examples of thoroughly studied hazard cascades. Mitigating the effects of
climate change will require investigating these complex interactions, including these events in risk analysis
and planning, establishing consistent monitoring systems to be better prepared for future hazard cascades
(Bowman etal.,2020; Royal Commission into National Natural Disaster Arrangements,2020), and increas-
ing adaptive capacity in affected regions.
Data Availability Statement
Gridded rainfall data were obtained from the Australian Bureau of Meteorology and is available at http://
www.bom.gov.au/climate/maps/rainfall. Station rainfall data were obtained from the Australian Bureau of
Meteorology and is available at http://www.bom.gov.au/climate/data. Discharge and turbidity data were
obtained from the State of NSW (Lands and Water) and is available at http://www.bom.gov.au/waterda-
ta. The soil erosion data from the State Government of NSW and Department of Planning, Industry and
Environment is available at https://datasets.seed.nsw.gov.au/dataset/modelled-hillslope-erosion-over-new-
south-wales. Landsat OLI imagery is available from the US Geological Survey (https://www.earthexplor-
er.usgs.gov). Images from Sentinel are from Sentinel Playground, https://apps.sentinel-hub.com/senti-
nel-playground, Sinergise Ltd.
References
AghaKouchak, A., Huning, L. S., Chiang, F., Sadegh, M., Vahedifard, F., Mazdiyasni, O., etal. (2018). How do natural hazards cascade to
cause disasters?Nature, 561(7724), 458–460. https://doi.org/10.1038/d41586-018-06783-6
Alexandra, J., & Finlayson, C. M. (2020). Floods after bushfires: rapid responses for reducing impacts of sediment, ash, and nutrient slugs.
Australasian Journal of Water Resources, 24(1), 9–11. https://doi.org/10.1080/13241583.2020.1717694
Alleaume, S., Hely, C., Le Roux, J., Korontzi, S., Swap, R., Shugart, H., & Justice, C. (2005). Using MODIS to evaluate heterogeneity of
biomass burning in southern African savannahs: a case study in Etosha. International Journal of Remote Sensing, 26(19), 4219–4237.
Atkinson, G. (2012). Soil erosion following wildfire in Royal National Park, NSW. Proceedings of the Linnean Society of New South Wales,
134, pp. 25–38.
Baldwin, C., & Ross, H. (2020). Beyond a tragic fire season: A window of opportunity to address climate change?Australasian Journal of
Environmental Management, 27(1), 1–5. https://doi.org/10.1080/14486563.2020.1730572
Barrett, T. (2006). Modelling burn severity for the 2003 NSW/ACT wildfires using landsat imagery, Life in a fire-prone environment: translat-
ing science into practice, Brisbane: Proceedings of the Bushfire Conference.
Blake, D., Nyman, P., Nice, H., D'souza, F. M. L., Kavazos, C. R. J., & Horwitz, P. (2020). Assessment of post-wildfire erosion risk and effects
on water quality in south-western Australia. International Journal of Wildland Fire, 29(3), 240–257. https://doi.org/10.1071/WF18123
Boer, M. M., Resco de Dios, V., & Bradstock, R. A. (2020). Unprecedented burn area of Australian mega forest fires. Nature Climate Change,
10(3), 171–172. https://doi.org/10.1038/s41558-020-0716-1
Borchers Arriagada, N., Palmer, A. J., Bowman, D. M., Morgan, G. G., Jalaludin, B. B., & Johnston, F. H. (2020). Unprecedented smoke
related health burden associated with the 2019–20 bushfires in eastern Australia. Medical Journal of Australia, 213, 282–283. https://
doi.org/10.5694/mja2.50545
Bowman, D., Williamson, G., Yebra, M., Lizundia-Loiola, J., Pettinari, M. L., Shah, S., etal. (2020). Wildfires: Australia needs national
monitoring agency. Nature, 584(7820), 188–191. https://doi.org/10.1038/d41586-020-02306-4
Bradstock, R. A., Nolan, R. H., Collins, L., Resco de Dios, V., Clarke, H., Jenkins, M., etal. (2020). A broader perspective on the causes and
consequences of eastern Australia's 2019-20 season of mega-fires: A response to Adams etal. Global Change Biology, 26, e8–e9.
KEMTER ET AL.
10.1029/2020EF001884
5 of 7
Acknowledgments
This research was funded by the DFG
Research Training Group “Natural Haz-
ards and Risks in a Changing World''
(NatRisk Change GRK 2043) and the
DFG International Research Training
Group “Surface processes, Tectonics,
and Georesources: The Andean fore-
land basin of Argentina” (StRATEGy
IGK 2018) at the University of Potsdam
(https://www.natriskchange.de, https://
irtg-strategy.de).
Earth’s Future
Chafer, C. J. (2008). A comparison of fire severity measures: An Australian example and implications for predicting major areas of soil
erosion. CATENA, 74(3), 235–245. https://doi.org/10.1016/j.catena.2007.12.005
Davey, S. M., & Sarre, A. (2020). Editorial: The 2019/20 Black Summer bushfires. Australian Forestry, 83(2), 47–51. https://doi.org/10.108
0/00049158.2020.1769899
Deb, P., Moradkhani, H., Abbaszadeh, P., Kiem, A. S., Engström, J., Keellings, D., & Sharma, A. (2020). Causes of the widespread 2019–
2020 Australian bushfire season. Earth's Future, 8(11), e2020EF001671. https://doi.org/10.1029/2020EF001671
French, N. H., Kasischke, E. S., Hall, R. J., Murphy, K. A., Verbyla, D. L., Hoy, E. E., & Allen, J. L. (2008). Using Landsat data to assess fire
and burn severity in the North American boreal forest region: An overview and summary of results. International Journal of Wildland
Fire, 17(4), 443–462.
Gill, J. C., & Malamud, B. D. (2016). Hazard interactions and interaction networks (cascades) within multi-hazard methodologies. Earth
System Dynamics, 7(3), 659–679. https://doi.org/10.5194/esd-7-659-2016
Hegerl, G. C., Hanlon, H., & Beierkuhnlein, C. (2011). Elusive extremes. Nature Geoscience, 4(3), 142–143. https://doi.org/10.1038/
ngeo1090
Hughes, L., Steffen, W., Mullins, G., Dean, A., Weisbrot, E., & Rice, M. (2020). Summer of crisis. Climate Council of Australia.
Insurance Council of Australia. (2020). Insurance bill for season of natural disasters climbs over $5.19 billion, Sydney: Insurance Council of
Australia. Retrieved from https://www.insurancecouncil.com.au/media_release/plain/575
Irannezhad, M., Liu, J., Ahmadi, B., & Chen, D. (2020). The dangers of Arctic zombie wildfires. Science, 369(6508), 1171. https://doi.
org/10.1126/science.abe1739
Jones, D. A., Wang, W., & Fawcett, R. (2009). High-quality spatial climate data-sets for Australia. Australian Meteorological and Oceano-
graphic Journal, 58(4), 233–248. https://doi.org/10.22499/2.5804.003
Kablick, III, G. P., Allen, D. R., Fromm, M. D., & Nedoluha, G. E. (2020). Australian PyroCb Smoke Generates Synoptic-Scale Stratospheric
Anticyclones. Geophysical Research Letters, 47(13), e2020GL088101. https://doi.org/10.1029/2020GL088101
Kappes, M. S., Keiler, M., von Elverfeldt, K., & Glade, T. (2012). Challenges of analyzing multi-hazard risk: a review. Natural Hazards,
64(2), 1925–1958. https://doi.org/10.1007/s11069-012-0294-2
Key, C. H., & Benson, N. C. (2002). Remote sensing measure of severity, the normalized burn ratio. In J. L.Coffelt & R. K.Livingston (Eds.),
Fire effects monitoring and inventory protocol, landscape assessment (p. 55). Washington, D.C: U.S.Geological Surveyeditors
Key, C. H., & Benson, N. C. (2006). Landscape assessment (LA). In D. C.Lutes,R. E.Keane,J. F.Caratti,C. H.Key,N. C.Benson,S.Sutherland &
L. J.Gangi (Eds.), FIREMON: Fire effects monitoring and inventory system (Gen. Tech. Rep. RMRS-GTR-164-CD) (p. 1–51). Fort Collins,
CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station.
Kharin, V. V., & Zwiers, F. W. (2005). Estimating extremes in transient climate change simulations. Journal of Climate, 18(8), 1156–1173.
https://doi.org/10.1175/JCLI3320.1
King, A. D., Pitman, A. J., Henley, B. J., Ukkola, A. M., & Brown, J. R. (2020). The role of climate variability in Australian drought. Nature
Climate Change, 10(3), 177–179. https://doi.org/10.1038/s41558-020-0718-z
Kinnell, P. I. A. (2010). Event soil loss, runoff and the universal soil loss equation family of models: A review. Journal of Hydrology,
385(1–4), 384–397. https://doi.org/10.1016/j.jhydrol.2010.01.024
Larsen, I. J., & MacDonald, L. H. (2007). Predicting postfire sediment yields at the hillslope scale: Testing RUSLE and disturbed WEPP.
Water Resources Research, 43(11), W11412. https://doi.org/10.1029/2006WR005560
Lentile, L. B., Holden, Z. A., Smith, A. M. S., Falkowski, M. J., Hudak, A. T., Morgan, P., etal. (2006). Remote sensing techniques to assess
active fire characteristics and post-fire effects. International Journal of Wildland Fire, 15(3), 319. https://doi.org/10.1071/WF05097
McAneney, J., Sandercock, B., Crompton, R., Mortlock, T., Musulin, R. R. P., Jr, & Gissing, A. (2019). Normalised insurance losses from
Australian natural disasters: 1966–2017. Environmental Hazards, 18(5), 414–433https://doi.org/10.1080/17477891.2019.1609406
Nolan, R. H., Boer, M. M., Collins, L., Resco de Dios, V., Larke, H., Jenkins, M., etal. (2020). Causes and consequences of eastern Australia's
2019-20 season of mega-fires. Global Change Biology, 26(3), 1039–1041. https://doi.org/10.1111/gcb.14987
Pescaroli, G., & Alexander, D. (2015). A definition of cascading disasters and cascading effects: Going beyond the “toppling dominos”
metaphor. Planet@Risk, 3(1), 58–67.
Pickrell, J., & Pennisi, E. (2020). Record U.S. and Australian fires raise fears for many species. Science, 370, 18–19. https://doi.org/10.1126/
science.370.6512.18
Renard, G. K., Foster, G. R., Weesies, G. A., & Porter, J. I. (1991). RUSLE: Revised universal soil loss equation. Journal of Soil and Water
Conservation, 46(1), 30–33. https://doi.org/10.1007/springerreference_77104
Royal Commission into National Natural Disaster Arrangements. (2020). Royal Commission into national natural disaster Arrange-
ments: Report. Canberra: Commonwealth of Australia. Retrieved from https://naturaldisaster.royalcommission.gov.au/publications/
royal-commission-national-natural-disaster-arrangements-report
Schauwecker, S., Gascón, E., Park, S., Ruiz-Villanueva, V., Schwarb, M., Sempere-Torres, D., etal. (2019). Anticipating cascading effects of
extreme precipitation with pathway schemes - Three case studies from Europe. Environment International, 127, 291–304. https://doi.
org/10.1016/j.envint.2019.02.072
Shakesby, R., & Doerr, S. (2006). Wildfire as a hydrological and geomorphological agent. Earth-Science Reviews, 74(3–4), 269–307. https://
doi.org/10.1016/j.earscirev.2005.10.006
Sharma, A., Wasko, C., & Lettenmaier, D. P. (2018). If precipitation extremes are increasing, why aren't floods?Water Resources Research,
54(11), 8545–8551. https://doi.org/10.1029/2018WR023749
Soverel, N. O., Perrakis, D. D., & Coops, N. C. (2010). Estimating burn severity from Landsat dNBR and RdNBR indices across western
Canada. Remote Sensing of Environment, 114(9), 1896–1909.
Van Oldenborgh, G. J., Krikken, F., Lewis, S., Leach, N. J., Lehner, F., Saunders, K. R., etal. (2021). Attribution of the Australian bushfire
risk to anthropogenic climate change. Natural Hazards and Earth System Sciences. https://doi.org/10.5194/nhess-2020-69
Vardoulakis, S., Jalaludin, B. B., Morgan, G. G., Hanigan, I. C., & Johnston, F. H. (2020). Bushfire smoke: urgent need for a national health
protection strategy. Medical Journal of Australia, 212(8), 349–353.
Victorian Bushfires Royal Commission. (2010). Final report. Melbourne: Parliament of Victoria. Retrieved from http://royalcommission.
vic.gov.au/Commission-Reports/Final-Report/Volume-1/High-Resolution-Version.html
Walz, Y., Maier, S. W., Dech, S. W., Conrad, C., & Colditz, R. R. (2007). Classification of burn severity using Moderate Resolution Imaging
Spectroradiometer (MODIS): A case study in the jarrah-marri forest of southwest Western Australia. Journal of Geophysical Research,
112, G02002. https://doi.org/10.1029/2005JG000118
Wasko, C., & Nathan, R. (2019). Influence of changes in rainfall and soil moisture on trends in flooding. Journal of Hydrology, 575,
432–441. https://doi.org/10.1016/j.jhydrol.2019.05.054
KEMTER ET AL.
10.1029/2020EF001884
6 of 7
Earth’s Future
Whelan, R. (2020). Lessons to be learned in relation to the preparation and planning for, response to and recovery efforts following the 2019-20
Australian bushfire season: Opening Statement, Sydney: Insurance Council of Australia. Retrieved from http://www.insurancecoun-
cil.com.au/assets/media_release/2020/100720%20Opening%20Statement%20-%20Senate%20inquiry%20into%20lessons%20from%20
the%20bushfire%20season.pdf
Yang, X. (2015). Digital mapping of RUSLE slope length and steepness factor across New South Wales, Australia. Soil Research, 53(2),
216–225.
Yang, X., Gray, J., Chapman, G., Zhu, Q., Tulau, M., & McInnes-Clarke, S. (2018). Digital mapping of soil erodibility for water erosion in
New South Wales, Australia. Soil Research, 56(2), 158–170.
Zscheischler, J., Martius, O., Westra, S., Bevacqua, E., Raymond, C., Horton, R. M., etal. (2020). A typology of compound weather and
climate events. Nature Reviews Earth & Environment, 1(7), 333–347. https://doi.org/10.1038/s43017-020-0060-z
Zscheischler, J., & Seneviratne, S. I. (2017). Dependence of drivers affects risks associated with compound events. Science Advances, 3(6),
e1700263. https://doi.org/10.1126/sciadv.1700263
Zscheischler, J., vanden Hurk, B., Ward, P. J., & Westra, S. (2020). Multivariate extremes and compound events. In J.Sillmann, S.Sippel,
& S.Russo (Eds.), Climate extremes and their implications for impact and risk assessment (pp. 59–76). Amsterdam: Elsevier. https://doi.
org/10.1016/B978-0-12-814895-2.00004-5
Zscheischler, J., Westra, S., van den Hurk, B. J. J. M., Seneviratne, S. I., Ward, P. J., Pitman, A., etal. (2018). Future climate risk from com-
pound events. Nature Climate Change, 8(6), 469–477. https://doi.org/10.1038/s41558-018-0156-3
KEMTER ET AL.
10.1029/2020EF001884
7 of 7