Broad-Scale Surface and Atmospheric Conditions during Large Fires in South-Central Chile
The unprecedented size of the 2017 wildfires that burned nearly 600,000 hectares of central Chile highlight a need to better understand the climatic conditions under which large fires develop. Here we evaluate synoptic atmospheric conditions at the surface and free troposphere associated with anomal...
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doaj-3202705a664746c4bd1f550460b6804d2021-06-01T00:08:48ZengMDPI AGFire2571-62552021-05-014282810.3390/fire4020028Broad-Scale Surface and Atmospheric Conditions during Large Fires in South-Central ChileDavid B. McWethy0René D. Garreaud1Andrés Holz2Gregory T. Pederson3Department of Earth Sciences, Montana State University, Bozeman, MT 59717, USADepartment of Geophysics, Universidad de Chile, Santiago 8320000, ChileDepartment of Geography, Portland State University, Portland, OR 97201, USAU.S. Geological Survey, Northern Rocky Mountain Science Center, Bozeman, MT 59715, USAThe unprecedented size of the 2017 wildfires that burned nearly 600,000 hectares of central Chile highlight a need to better understand the climatic conditions under which large fires develop. Here we evaluate synoptic atmospheric conditions at the surface and free troposphere associated with anomalously high (active) versus low (inactive) months of area burned in south-central Chile (ca. 32–41° S) from the Chilean Forest Service (CONAF) record of area burned from 1984–2018. Active fire months are correlated with warm surface temperatures, dry conditions, and the presence of a circumpolar assemblage of high-pressure systems located ca. 40°–60° S. Additionally, warm surface temperatures associated with active fire months are linked to reduced strength of cool, onshore westerly winds and an increase in warm, downslope Andean Cordillera easterly winds. Episodic warm downslope winds and easterly wind anomalies superimposed on long-term warming and drying trends will continue to create conditions that promote large fires in south-central Chile. Identifying the mechanisms responsible for easterly wind anomalies and determining whether this trend is strengthening due to synoptic-scale climatic changes such as the poleward shift in Southern Hemisphere westerly winds will be critical for anticipating future large fire activity in south-central Chile.https://www.mdpi.com/2571-6255/4/2/28fireclimateChilelarge firesfire weatherENSO |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
David B. McWethy René D. Garreaud Andrés Holz Gregory T. Pederson |
spellingShingle |
David B. McWethy René D. Garreaud Andrés Holz Gregory T. Pederson Broad-Scale Surface and Atmospheric Conditions during Large Fires in South-Central Chile Fire fire climate Chile large fires fire weather ENSO |
author_facet |
David B. McWethy René D. Garreaud Andrés Holz Gregory T. Pederson |
author_sort |
David B. McWethy |
title |
Broad-Scale Surface and Atmospheric Conditions during Large Fires in South-Central Chile |
title_short |
Broad-Scale Surface and Atmospheric Conditions during Large Fires in South-Central Chile |
title_full |
Broad-Scale Surface and Atmospheric Conditions during Large Fires in South-Central Chile |
title_fullStr |
Broad-Scale Surface and Atmospheric Conditions during Large Fires in South-Central Chile |
title_full_unstemmed |
Broad-Scale Surface and Atmospheric Conditions during Large Fires in South-Central Chile |
title_sort |
broad-scale surface and atmospheric conditions during large fires in south-central chile |
publisher |
MDPI AG |
series |
Fire |
issn |
2571-6255 |
publishDate |
2021-05-01 |
description |
The unprecedented size of the 2017 wildfires that burned nearly 600,000 hectares of central Chile highlight a need to better understand the climatic conditions under which large fires develop. Here we evaluate synoptic atmospheric conditions at the surface and free troposphere associated with anomalously high (active) versus low (inactive) months of area burned in south-central Chile (ca. 32–41° S) from the Chilean Forest Service (CONAF) record of area burned from 1984–2018. Active fire months are correlated with warm surface temperatures, dry conditions, and the presence of a circumpolar assemblage of high-pressure systems located ca. 40°–60° S. Additionally, warm surface temperatures associated with active fire months are linked to reduced strength of cool, onshore westerly winds and an increase in warm, downslope Andean Cordillera easterly winds. Episodic warm downslope winds and easterly wind anomalies superimposed on long-term warming and drying trends will continue to create conditions that promote large fires in south-central Chile. Identifying the mechanisms responsible for easterly wind anomalies and determining whether this trend is strengthening due to synoptic-scale climatic changes such as the poleward shift in Southern Hemisphere westerly winds will be critical for anticipating future large fire activity in south-central Chile. |
topic |
fire climate Chile large fires fire weather ENSO |
url |
https://www.mdpi.com/2571-6255/4/2/28 |
work_keys_str_mv |
AT davidbmcwethy broadscalesurfaceandatmosphericconditionsduringlargefiresinsouthcentralchile AT renedgarreaud broadscalesurfaceandatmosphericconditionsduringlargefiresinsouthcentralchile AT andresholz broadscalesurfaceandatmosphericconditionsduringlargefiresinsouthcentralchile AT gregorytpederson broadscalesurfaceandatmosphericconditionsduringlargefiresinsouthcentralchile |
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