Fire Weather Drivers, Seasonal Outlook and Climate Change Steven McGibbony, Severe Weather Manager Victoria Region Friday 9 October 2015
Outline Weather and Fire Risk Environmental conditions leading to increased fire risk The Bureau's fire weather services Recent and Current conditions Rainfall and temperatures in 2015 The El Niño -Southern Oscillation The Climate Outlook Climate Change and Fire Weather
Environmental conditions leading to increased fire danger Four factors that influence fire behaviour temperature, humidity, wind, state of fuels These are combined to create a Fire Danger Index The higher the index, the greater the likelihood that a fire will be difficult to control.
What does a high fire risk day for Victoria look like?
Fire Weather Products District Fire Danger Ratings Fire Weather Warnings Fire Weather Forecast Fire Danger Graphical Maps Thunderstorm Forecast Charts Spot Fire Weather Forecasts Wind Change Forecast Maps
State Control Centre Meteorologist Victoria's emergency services pay for an additional resource from the Bureau a forecaster permanently positioned in the State Control Centre. Provide forecast advice to aid planned burning. 7-day a week coverage during the Fire Weather Season providing a briefing role. Prepare numerous additional products specifically tailored to emergency service needs.
Longer term context 2015 10 years (April 2005 to October 2014) cool season rainfall deciles 10 years (2005-2014) maximum temperature deciles
Rainfall in 2015 October 2014 to April 2015 rainfall deciles May to September rainfall deciles 2015.
Temperatures in 2015 March to May maximum temperature deciles June to September maximum temperature deciles
El Niño Status August 2015
ENSO tracker ENSO Tracker remains in El Niño El Niño to continue through to end of year
El Niño temperature impacts Typical winter spring El Niño maximum temperature
El Niño rainfall impacts Historical rainfall deciles from 12 moderate-strong El Niños Rainfall for September to November Rainfall for December to February
Variability in El Niño impacts Winter Winter and and spring spring rainfall deciles deciles for for 1982 El Niño Winter and spring rainfall deciles for 1997 El Niño Winter and spring rainfall deciles for 1997 El Niño
1950 1953 1956 1959 1962 1965 1968 1971 1974 1977 1980 1983 1986 1989 1992 1995 1998 2001 2004 2007 2010 2013 Strong El Niño in Pacific and warm Indian Ocean Strong El Niño in Pacific Indian Ocean is at record warmth Sea surface temperature anomalies September 2015 Influence of both oceans may confound rainfall impacts over Australia 0.8 0.6 0.4 0.2 0-0.2-0.4-0.6 1982 July temperature anomalies Southern Indian Ocean 1997 2015 Indian Ocean Data: ERSST v4 1981 2010 base period 0 40 S 30 120 E
Rainfall outlook October Probability of above median rainfall for October to December 2015 and the months october and November November
Temperature outlooks Probability of above median maximum temperature for October to December 2015 Probability of above median minimum temperature for October to December 2015
Other impacts Hazard Bushfire Heatwave Tropical Cyclone landfall (Qld east coast) Tropical Cyclone landfall (NT & WA) Widespread Flooding (eastern Australia) Likelihood in El Niño years compared to neutral years More likely More likely Less likely Similar Less likely
Bushfire potential Issued September 2015
Heatwaves: Increased risk A heatwave is 3 days or more of above normal temperatures. Monitor forecasts available at http://www.bom.gov.au/australia/heatwave/index.shtml
Severe thunderstorms Severe thunderstorms can form at anytime of the season Severe thunderstorms produce any of the following: Hailstones 2cm diameter Wind gusts 90km/h Flash flooding Tornadoes Photo by Chris Kent
Climate Change Impacts
Climate Change Impacts
Number of occurrences (months/year) Climate Change Impacts "Since 2001, the number of extreme heat records in Australia has outnumbered extreme cool records by almost 3 to 1 for daytime maximum temperatures, and almost 5 to 1 for nighttime minimum temperatures." Maximum temperature anomaly ( C)
Climate Change Impacts Southern season rainfall deciles since 1996.
Climate Change Impacts Annual cumulative FFDI changes from 1973-2010. Largest increases have been in the SE and away from the coast. >> The fire season is becoming longer.
Future Climate Scenarios Australian temperatures are projected to continue to increase, with more hot days and fewer cool days. Average rainfall in southern Australia is projected to decrease, with a likely increase in drought frequency and severity. A further increase in the number of extreme fire-weather days is expected in southern and eastern Australia, with a longer fire season in these regions.
Summary 2015 another warmer than average year despite some cold outbreaks El Niño is a dominant climate driver of weather patterns this season Changes in risk compared to normal summer Increased risk of bushfire in many areas due to dry and warm conditions Increased risk of heatwaves in summer months Decreased risk of widespread flooding, Localised flood risk remains possibility during El Niño Severe thunderstorms are ALWAYS possible Climate Change is likely to result in an increase in the length of the fire season