The 2017 Split wildfire in Croatia: evolution  and the role of meteorological conditions

Čavlina Tomašević, Ivana; Cheung, Kevin K. W.; Vučetić, Višnjica; Fox-Hughes, Paul; Horvath, Kristian; Telišman Prtenjak, Maja; Beggs, Paul J.; Malečić, Barbara; Milić, Velimir

doi:https://doi.org/10.5194/nhess-22-3143-2022

Articles | Volume 22, issue 10

Nat. Hazards Earth Syst. Sci., 22, 3143–3165, 2022

https://doi.org/10.5194/nhess-22-3143-2022

© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.

Nat. Hazards Earth Syst. Sci., 22, 3143–3165, 2022

https://doi.org/10.5194/nhess-22-3143-2022

© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.

Articles | Volume 22, issue 10

Research article

06 Oct 2022

Research article | 06 Oct 2022

The 2017 Split wildfire in Croatia: evolution and the role of meteorological conditions

Ivana Čavlina Tomašević et al.

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Final revised paper (published on 06 Oct 2022)
Preprint (discussion started on 04 May 2022)

Interactive discussion

Status: closed

RC1:
'Comment on nhess-2022-116', Anonymous Referee #1, 15 Jun 2022

The paper is very well written and could be accepted as is. It is good to see this type of research for Croatia. Below are two very minor comments for consideration:

Line 53: Perhaps indicate if this is a regional or otherwise statistic so that readers do not necessarily have to look up the reference.

Line 60: Perhaps consider adding a more recent critical fire weather pattern publication such as https://landscapepartnership.org/maps-data/climate-context/cc-resources/ClimateSciPDFs/JFSP%20Extreme%20Fire.pdf/app-download-file/file/JFSP%20Extreme%20Fire.pdf#page=37

General: Perhaps consider summarizing in the conclusions section the uniqueness of the environmental conditions enabling and driving this fire.

Citation: https://doi.org/10.5194/nhess-2022-116-RC1
- CC1:
  'Reply on RC1', kevin cheung, 16 Jun 2022
  
  Dear Referee,
  We are glad to have received your positive review of our manuscript and your support of our study for this region that has nto appeared in the literature much.
  Thanks for the comments including the additional reference. We will revise according to them in the revised version.
  On behalf of the corresponding author and all other co-authors.
  
  Citation: https://doi.org/10.5194/nhess-2022-116-CC1
  - AC1: 'Reply on RC1', Ivana Cavlina Tomasevic, 27 Jul 2022
    
    The paper is very well written and could be accepted as is. It is good to see this type of research for Croatia. Below are two very minor comments for consideration:
    Response: We appreciate the appraisal from the reviewer, and the support for this study for Croatia that has not been exposed much in the literature. When we prepare the final manuscript we will revise according to these minor comments as in our responses below.
    Line 53: Perhaps indicate if this is a regional or otherwise statistic so that readers do not necessarily have to look up the reference.
    Response: This statement was based on Strauss et al. (1989), which has validated some theoretical fire size distributions by data from western U.S., and thus regional statistics. We will revised the statement as “Extreme wildfires are rare, based on statistics from western U.S. they account for only 1 % of fire occurrences but cause more than 90% of damage (Strauss et al., 1989).”
    Line 60: Perhaps consider adding a more recent critical fire weather pattern publication such as https://landscapepartnership.org/maps-data/climate-context/cc-resources/ClimateSciPDFs/JFSP%20Extreme%20Fire.pdf/app-download-file/file/JFSP%20Extreme%20Fire.pdf#page=37
    Response: Thank you for the suggested additional reference. We will quote this reference (Werth 2011) in the final manuscript.
    General: Perhaps consider summarizing in the conclusions section the uniqueness of the environmental conditions enabling and driving this fire.
    Response: Thanks for this suggestion. Perhaps we have not named section 5 well enough. The environmental conditions enabling and driving this fire have been detailed in 5.1, and 5.2 and 5.3 are dedicated to further discussion. For better clarity, we will renamed section 5 as “Summary and Conclusion”, and for the sub-sections “5.1 Summary”, “5.2 Further discussion on the dynamics of bura” (according to a comment from RC2) and “5.3 Concluding remarks”.
    
    Citation: https://doi.org/10.5194/nhess-2022-116-AC1
- AC1: 'Reply on RC1', Ivana Cavlina Tomasevic, 27 Jul 2022
  
  The paper is very well written and could be accepted as is. It is good to see this type of research for Croatia. Below are two very minor comments for consideration:
  Response: We appreciate the appraisal from the reviewer, and the support for this study for Croatia that has not been exposed much in the literature. When we prepare the final manuscript we will revise according to these minor comments as in our responses below.
  Line 53: Perhaps indicate if this is a regional or otherwise statistic so that readers do not necessarily have to look up the reference.
  Response: This statement was based on Strauss et al. (1989), which has validated some theoretical fire size distributions by data from western U.S., and thus regional statistics. We will revised the statement as “Extreme wildfires are rare, based on statistics from western U.S. they account for only 1 % of fire occurrences but cause more than 90% of damage (Strauss et al., 1989).”
  Line 60: Perhaps consider adding a more recent critical fire weather pattern publication such as https://landscapepartnership.org/maps-data/climate-context/cc-resources/ClimateSciPDFs/JFSP%20Extreme%20Fire.pdf/app-download-file/file/JFSP%20Extreme%20Fire.pdf#page=37
  Response: Thank you for the suggested additional reference. We will quote this reference (Werth 2011) in the final manuscript.
  General: Perhaps consider summarizing in the conclusions section the uniqueness of the environmental conditions enabling and driving this fire.
  Response: Thanks for this suggestion. Perhaps we have not named section 5 well enough. The environmental conditions enabling and driving this fire have been detailed in 5.1, and 5.2 and 5.3 are dedicated to further discussion. For better clarity, we will renamed section 5 as “Summary and Conclusion”, and for the sub-sections “5.1 Summary”, “5.2 Further discussion on the dynamics of bura” (according to a comment from RC2) and “5.3 Concluding remarks”.
  
  Citation: https://doi.org/10.5194/nhess-2022-116-AC1
RC2:
'Comment on nhess-2022-116', Anonymous Referee #2, 10 Jul 2022
General comments

The comprehensive analysis and diagnosis of weather and associated fire behaviour of the 2017 Split wildfire in Croatia were presented in this study. The manuscript is well written, and the analysis and discussions flow well. The scientific questions are well defined in the study and the results from analysis presented as figures and tables provide good supports to the answers.

Very happy to see the robust discussions of how synoptic, mesoscale, and local weather influence fire behaviour in this study. But we know wildfires would also simultaneously impact weather, hope to see there's a future study on the feedback from Split wildfire to the local weather too.

A Few technical comments are listed below

Figure 8 and Figure 10 are not referenced in the main text

Lines 530 to 553 seems only presenting discussions on Bura (section 5.2), and discussion on LLJ appear after line 554 (section 5.3). If that is the case, title of section should be amended to only include Bura.
Citation: https://doi.org/10.5194/nhess-2022-116-RC2
- AC2:
  'Reply on RC2', Ivana Cavlina Tomasevic, 27 Jul 2022
  General comments
  The comprehensive analysis and diagnosis of weather and associated fire behaviour of the 2017 Split wildfire in Croatia were presented in this study. The manuscript is well written, and the analysis and discussions flow well. The scientific questions are well defined in the study and the results from analysis presented as figures and tables provide good supports to the answers.
  Response: We appreciate the appraisal from the reviewer. When we prepare the final manuscript we will revise according to your minor comments as in our responses below.
  Very happy to see the robust discussions of how synoptic, mesoscale, and local weather influence fire behaviour in this study. But we know wildfires would also simultaneously impact weather, hope to see there's a future study on the feedback from Split wildfire to the local weather too.
  Response: Thank you for this insightful comment. We agree that the heat and moisture from the wildfire event may has modified the weather (which consisted of the large pressure gradient and the LLJ). We are performing numerical modelling of the event using both weather model and weather-fire coupled model, and based on which will diagnose such feedback processes. We will mention this as future research in the concluding remarks.
  A Few technical comments are listed below
  Figure 8 and Figure 10 are not referenced in the main text
  
  Response: Thank you for pointing this out. We will add quotation of these two figures in the final manuscript.
  Lines 530 to 553 seems only presenting discussions on Bura (section 5.2), and discussion on LLJ appear after line 554 (section 5.3). If that is the case, title of section should be amended to only include Bura.
  
  Response: Thank you for this suggestion and we are sorry about the confusion. Also based on a comment from RC1, we will rename section 5 as “Summary and Conclusion”, and for the sub-sections “5.1 Summary”, “5.2 Further discussion on the dynamics of bura” and “5.3 Concluding remarks”.
  
  Citation: https://doi.org/10.5194/nhess-2022-116-AC2

Peer review completion

AR: Author's response | RR: Referee report | ED: Editor decision

ED: Publish subject to minor revisions (review by editor) (04 Aug 2022) by Maria-Carmen Llasat

Dear Dr. Ivana Čavlina and coauthors

Thank you for the submission of your very interesting manuscript “The 2017 Split wildfire in Croatia: Evolution and the role of meteorological conditions”.

As you know, two reviewers have now provided detailed reviews, which you have replied in thoughtful detail to. Both reviewers recommended minor revisions (although I have a feeling some of the revisions suggested are not so minor--they may take a bit of time!), and therefore I would like to invite you to submit a revised version of your manuscript.

Would you please also provide an ‘author’s reply’ to the reviewers (feel free to use the same words that you used in what you have already uploaded). Please can you also include a track changes document between the old manuscript and the new one (you can include this as part of your ‘author’s reply’).

In addition to the suggestions from the reviewers, I would like to suggest the following technical items, in most cases ‘minor’:

Abstract is so much long. Please, synthesize it. It is not necessary to go into so many details. It is enough to introduce the case study, the sources of information and methodology and the most notable results. Everything is usually written in a single paragraph in less than 20 lines.

Line 51: add the year of the wildfires in California

Line 58. You say, “The local state of the atmosphere in days prior to wildfire and during wildfire activity is determined by synoptic scale weather systems”. I am not sure that this statement is correct, as it is demonstrated throughout the article. There are several local factors that do not necessarily depend on synoptic features. For example, the slope winds to which the paper refers, or the sudden changes in wind direction. The synoptic configurations that have prevailed before the fires are very important in order to justify the state of the fuel (mainly the vegetation), but the start and spread of the fire depends mainly on mesoscale factors, as shown in the article.

Line 94. It would be better to write the sentence “Research on fire weather…” in a new paragraph. It could be the same of the July 2017 event.

Line 118. Please, clarify in the text if the number of ~2500 wildfires is the annual average (they could include very little forest fires) or the total for the period 2006-2016.
Paragraph lines 318-323. Cut-off low is usually associated to instability in high levels (and heavy rainfalls or severe weather in the eastern part, on some occasions). You speak about a “cool change”, what role do you think that this cool change and this cut-off low would play?

Lines 338-340. “from 33.3°C to 27.0°C between 15 and 16 July. This was followed by a drop in relative humidity” Are you sure? One of the most typical situations in the great wildfires is a sudden temperature increase. A decrease of 5ºC is very strange. And a decrease of temperature would produce an increase of relative humidity for the same specific humidity, and you say that relative humidity dropped. Are you sure?

Lines 437-438. “Dry conditions might be explained by the complete absence of the tropopause”. The tropopause exists always, although it can be upper its usual level.
Referee 1 says”: Perhaps consider summarizing in the conclusions section the uniqueness of the environmental conditions enabling and driving this fire.” I agree with him/her and reading your answer I am afraid that you have not understood him/her. Concluding remarks are so much long. I would propose you to focus in the meteorological and climatic (for antecedent conditions) factors that leaded to these great wildfires in Croatia in 2017, avoiding references and discussion. Discussion aspects, including comparison with other situations, could be moved to subsections 5.1. and 5.2

I look forward to seeing the next version of your manuscript which I will not send out for further review, but rather, will make the decision myself, assuming no major items come up in the revised manuscript for which I need outside reviewers to aid me in my decision. In your revisions, please address all the points made by first reviewer and me, make suitable edits to the manuscript, and include a point-by-point response to each comment with your response.

Once again, thank you for submitting your manuscript to NHESS journal. I look forward to receiving your revision.

Sincerely,

Prof. Maria Carmen Llasat
NHESS Editor

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AR by Ivana Cavlina Tomasevic on behalf of the Authors (16 Aug 2022) Author's response Author's tracked changes Manuscript

ED: Publish as is (02 Sep 2022) by Maria-Carmen Llasat

Short summary

One of the most severe and impactful urban wildfire events in Croatian history has been reconstructed and analyzed. The study identified some important meteorological influences related to the event: the synoptic conditions of the Azores anticyclone, cold front, and upper-level shortwave trough all led to the highest fire weather index in 2017. A low-level jet, locally known as bura wind that can be explained by hydraulic jump theory, was the dynamic trigger of the event.