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This article discusses the impacts of the 2006/7 El Niño on Australian climate and the bushfire season. It explores the typical climate response to El Niño/La Niña, the rainfall and temperature response, impacts on water availability, economic impacts, and the long-term drought in southeastern Australia. It also covers the bushfires in southeastern Australia and their impacts on the 2006-7 bushfire season.
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Effects of the 2006/7 El Niño on Australian climate and bushfire season Brad Murphy National Climate Centre Australian Bureau of Meteorology
Outline • ENSO impacts in Australia • typical climate response to El Niño / La Niña • 2006-7 El Niño in Australian region • rainfall and temperature response • impacts on water availability • economic impacts • Long-term drought in south eastern Australia • Bushfires in south eastern Australia • Impacts on 2006-7 Bushfire season
Typical El Niño rainfall response Jan Apr Jul Oct Jan Apr Jul Oct Jan
Previous Droughts and El Niño 2006 1994 2002 1982 1997
2006 Rainfall and Temp anomalies 30% of continent in decile 1 (Vic 93%, Tas 74%, South Aus. 50%) Alpine regions lowest on record
Records broken in 2006 • SE Aust Tmax +1.93°C (highest) • Southern Aust +1.85°C (highest) Record low minimum temperatures - severe, damaging frosts: • Major losses in the Goulburn Valley fruit crop (25 Sept –2.7°C at Wangaratta) • Crop losses in parts of SE Aus in Oct, particularly to grapes (29 Oct –12.0°C at Charlotte Pass (NSW), new Australian record low for Oct) Examples of lowest annual rainfall on record: • Harrietville, Vic., 503 mm (opened 1884, mean 1435 mm, previous record 707 mm in 1982) • Burnie, Tasmania, 408 mm (opened 1944, mean 950 mm, previous record 670 mm in 1972)
Rainfall Tmax Tmin Seasonal Outlooks from 2006 Winter Spring Statistical Outcome POAMA Model Dynamic
Long-term drought Last 10 years Last 5 years 50 year trend
Water storages/streamflows Lowest recorded inflows into Murray River system (40% of previous lowest record) Severe water restrictions in many urban and rural centres
Major Past Bushfires in Victoria • 1851 - 6 February 'Black Thursday’ • 5,000,000 hectares burnt, 12 lives lost, 2000 buildings • 1926 - February – March • 60 lives lost • 1939 - 13 January 'Black Friday’ • 2,000,000 hectares, 71 deaths, 650 buildings • 1944 • 15-20 deaths, 1 million hectares burnt • 1983 - 16 February 'Ash Wednesday’ • 100 fires, 47 deaths, 2000 houses lost • 2003 - Eastern Victorian (Alpine) Fires • 87 fires on 8 Jan, burnt for 59 days, 1.3 million hectares, 41 homes lost • Significant but smaller-scale fires also in: • 1898, 1932, 1942-44, 1952, 1962, 1965, 1968-9, 1972, 1977, 1980, 1985, 1988, 1997
Seasonal Bushfire Assessment 2006 - 2007 • Consensus assessment of bushfire potential in upcoming season • Participants from NCC, Research Centre and Regional Fire and Water Agencies • Modelled on U.S. National Seasonal Assessment Workshops • Considers recent climate, seasonal climate outlooks, current fuel loads and curing • Began in 2006, now split intoNorthern and Southern fire seasons Seasonal Fire Potential Outlook for 2006-7 Seasonal Fire Potential Outlook for 2007-8
Tasmanian Bushfires October 2006 • Record lowest rainfall Jan-Oct (232mm Hobart Airport - mean 402mm) • Record October max and min temps on 12th (33.4°C/17.0°C at Hobart Airport, averages 17.3°C/7.4°C) • Gale force winds on 11th and 12th • Extremely early start for fire season • Worst fires since 1967 • No homes or lives lost
Bairnsdale, SE Victoria, 2:30pm December 14. Alpine Fires December 2006 MODIS Rapid Response Project at NASA/GSFC 5 December 2006 • Lightning ignited 83 fires on 1 Dec, merging into one major complex • Longest fires in Victorian history (69 days) • 1,048,000 hectares burnt (10480km²) • 1 life lost (fire fighter - indirect) • 51 dwellings destroyed
MODIS Rapid Response Project at NASA/GSFC 12 December 2006 Near Chestnut, NE Victoria, 2pm 7 December. G. Arnoldussen Alpine Fires December 2006 • External fire-fighting resources brought in, highest ever international deployments: NSW 1,050, NT 108 SA 10, Qld 14, WA 20 Canada 52 New Zealand 115 USA 114 • Severe weather forecasting resources overloaded • season began earlier (September) • request made in September to US National Weather Service for fire weather forecasters to be deployed • ~ 16 forecasters arrived in January (Melbourne, Sydney, Hobart), invaluable in relieving over-worked/stressed local forecasters
FFDI = f(Ts, |V|, RH, Drought Factor) 2006: 10,480 km² Total area burnt2003: 13,000 km ² 1939:20,000 km²
Climate Change and Bushfires • Fire seasons are becoming longer and severe seasons more frequent • Forest Fire Danger Index (FFDI) projected to increase in southeast (except Tasmania) • More “extreme” fire days projected • 5-25% (low) and 15-65% (high emissions) by 2020 • 10-50% (low) and 100-300% (high) by 2050 From N. Nicholls (2007) From Lucas, et al. 2007
Summary • 2006 El Niño climate impacts typical for Australia • Dry/hot conditions followed long-term drought and warming trends • Impacts extreme, particularly on water resources and agriculture • Extreme fire conditions forecast in August • Major fires developed in Hobart (October) and Victorian Alps (December-January) • Longest fires in Victorian history, largest area burnt since 1939 • Resources stretched to limit, employments from interstate and abroad, losses minimised • Fire seasons getting more frequent and likely to become more severe