'Don’t Panic – Surviving Extremes': Bureau information

Bushfires, floods, tropical cyclones, heatwaves – Australians are all too familiar with extreme weather. But are you prepared for a natural disaster?

On Sunday 1 December 2013 ABC’s Catalyst broadcast a one-hour feature 'Don’t Panic – Surviving Extremes'.
Catalyst explored preparedness for extreme weather by throwing two ordinary Australian families into separate disaster scenarios – a catastrophic bushfire in NSW and a Category 3 tropical cyclone in the Tweed Heads region.

The Bureau of Meteorology provided the extreme weather scenarios, as well as information on Australia’s climate trends. This page includes the material we supplied to Catalyst, and links to critical Bureau pages to check during extreme weather events.

As highlighted by Catalyst, now is the time to 'Get Prepared'.

'Tropical cyclone Jonica'

Catalyst’s very own tropical cyclone Jonica was created to mimic a real event that affected South East Queensland and Northern New South Wales between 16–20 February 1954.

During this event, the edge of the eye passed over Coolangatta, with the worst damage in the Cudgen area in NSW. Widespread structural damage was also experienced in Brisbane and on the Gold and Sunshine coasts. A 0.64 m storm surge was recorded on the Moreton Bay gauge. The onshore impact of this surge resulted in boats being lodged in the tree tops at Beachmere.

Springbrook recorded 900 mm of rain in the 24 hour period prior to the system making landfall, and floods combined with storm surge on the Nerang River caused evacuations. The floods and cyclone then hit the Lismore district, with gales whipping up large waves on the Richmond River.

Parts of Byron Bay were flooded and the outer section of the jetty at Byron Bay was swept away, taking with it 22 vessels. Tragically, 30 people died during these events.

Bureau warnings for this scenario

Bushfire scenario

The Catalyst fire scenario presents a day of very strong west to north-westerly winds averaging up to 55 km/h, record high temperatures reaching 46°C in Sydney city, and very low relative humidity below 5 per cent. The Forest Fire Danger Index was said to exceed 'Severe' for 12 hours during the day, peaking at the 'Catastrophic' level from 2 pm to 8 pm. As part of the scenario, conditions leading up this day were said to be very dry.

Although the weather conditions in the scenario have yet to be experienced in a single day in Sydney, such conditions are not outside the realm of possibility as shown by weather readings in Sydney this year, as well as the culmination of such conditions occurring in other parts of the country.

On 18 January 2013, Sydney recorded 45.8°C, breaking the all-time temperature record for the capital city. On 10 September, hot, dry, north-westerly winds averaged between 45–55 km/h for the better part of an 8-hour period.

All that is required for the Catalyst weather scenario to play out is for these extreme weather conditions to align on the same day.

Prolonged periods of hot, dry westerly winds are a feature of Sydney’s worst bushfire weather conditions which generally occur in NSW in spring and early summer. Examples in recent years are the fires of the 1993–1994, 1997–1998, 2001–2002 and 2003–2004 summers.

From July 2013 New South Wales received very little rainfall. This, combined with an exceptionally warm winter and spring, contributed to much drier than average conditions that were made worse by persistent dry westerly winds and hot days. Widespread bushfires broke out during early October. The NSW RFS confirmed that a total of 208 homes were destroyed and 122 were damaged across the State during this event.

Related Bureau services

Australia’s climate trends

The below graphics were created by Catalyst for the Don't Panic special, using information provided by the Bureau of Meteorology. We have provided some explanatory text for each.

  • Extreme fire days

    Forest Fire Danger Index (FFDI) Trends 1973–2010

    The Forest Fire Danger Index is a measure of how favourable the weather and forest fuel conditions are to fires – it’s what’s behind the ‘Extreme Fire Danger’ readings you see on signs around the country. FFDI is calculated from a combination of temperature, humidity, and wind speed, as well as a measure of how dry the fuel is.

    This figure shows how the worst fire days have changed since 1973. Fire danger is increasing, especially in the southeast where rainfall has decreased. The largest increases have been in spring and autumn, making the fire season longer.

    Related information

    • Clarke, H., Lucas, C. and Smith, P. 2013. Changes in Australian fire weather between 1973 and 2010. Int. J. Climatol. 33. 931–944
    • The Guardian: Firestorm images
  • Fire weather

    Forest Fire Danger Index (FFDI) trends for Melbourne Airport

    If we zoom in on Melbourne Airport, we see how the fire danger added up across the whole fire season (total FFDI) has varied in recent years.

    Some years have higher fire danger and some lower, and fire danger is influenced by variations in the climate. Rain and flooding in 2010 and 2011 meant unusually low fire danger. But we can also see a long-term trend. The annual total FFDI is increasing, and bad fire years have occurred much more frequently during the last decade.

    Related information

    Lucas C. (2010) On developing a historical fire weather dataset for Australia. Australian Meteorological and Oceanographic Journal 60. 1–14

  • 1–18 January 2013

    A Summer of extreme heat in 18 days

    This figure shows the average daytime temperatures across Australia during 1–18 January 2013, with temperatures well above 40°C across most of the country. This was the most severe heatwave, and warmest January, since Australian records began in 1910. We have also seen an increased frequency of extreme heat, both in Australia and around the globe. During this period Australia recorded:

    • The hottest January and summer on record
    • The hottest day on record for Australia
    • The hottest day on record for Sydney and Hobart
    • Records across the country for extended warm spells
    • Severe bushfires in Tasmania

    Related information

  • Hottest days on record

    Records are, by definition, extreme. In more than a hundred years of data, the chances of breaking a new record are very low. But when we look at the hottest days on record across our capital cities, four of them were set during the last five years – Melbourne and Adelaide during the record-breaking heatwave before the Black Saturday bushfires of 2009, and Sydney and Hobart during the 2012–2013 record hot summer.

    Related information

  • Perth February temperature

    In the next decade we expect a temperature increase of about 0.2°C. Shifting this curve a little bit to the right means an increase in these warm days above 35°C.

    Related information

  • Perth February temperature

    Most scientists say that we’re ‘locked in’ to at least 1°C of temperature rise during the current century, just based on the amount of carbon already in the atmosphere.

    If we shift this temperature distribution up by 1°C, a much larger proportion of days have temperatures greater than 35°C, as shown by the increase in area to the right under the curve. This is even more noticeable for the more extreme events – the number of days above 40°C has almost doubled, while the very extreme days are now reaching 45°C.

    Related information

  • Perth February temperature

    This shows how a small increase in average temperatures can substantially change the number of those very hot days, which of course can have very significant health and bushfire impacts.

    With an increase of mean temperatures by 3°C, half of Perth February days are above 35°C. Days above 45°C are increasingly common, while almost no days drop below 20°C. Occasionally extreme day temperatures reach the high 40s, which was never seen in the current climate.

    Related information

  • Perth’s January daily maximum temperature

    The distribution of Perth’s January daily maximum temperatures during 1910–1939 shows a similar pattern. Most days are between about 24°C and 40°C, with very few days at the ‘tails’ – very hot or very cold.

    Related information

  • Heavy rain days

    Percentage of Australia experiencing extreme rainfall

    This figure looks at the proportion of rainfall that comes from extreme rain events – that is, the proportion of Australia where at least 90% of that year’s rain was due to extreme rain events (in the wettest 10% of days). Over the past century, we can see an increasing proportion of Australia’s rain is coming from these extreme rain events. So when it rains, the rain is heavier.

    In a warming climate, the atmosphere can hold a lot more water vapour – about 7% more for every degree of warming. This means a lot more water available for heavy rain events, even if the overall total rainfall decreases.

    Related information

    • Gallant, A. J. E. and D. J. Karoly, 2010: A combined Climate Extremes Index for the Australian region. Journal of Climate, 23, 6153–6165
    • Gallant, A. J. E. and D. J. Karoly, 2013: Consistent trends in a modified climate extremes index in the U.S.A, Europe and Australia. Journal of Climate, in press
  • Summer rainfall 2010–2012

    The wettest two-year period on record for Australia was the period between summer 2010 and summer 2012. This was associated with a strong La Niña event but also exceptionally warm sea surface temperatures around Australia, acting as a massive source of moisture.

    This figure shows the rainfall patterns for Australia between December 2010 to February 2012 with multiple new rainfall records set across the country. Almost the entire country recorded rain in the wettest 10% of years, with the exception of parts of southern Tasmania and southwest WA, with rainfall records smashed across the country.

    Related information

  • Extreme rainfall

    The very wet years were associated with a larger number of extreme rainfall events, many of which were associated with significant flooding, including the severe Brisbane floods of January 2011.

    Some particularly significant events include:

    • In January 2011, falls of 400 mm were recorded between Hervey Bay and Rockhampton.
    • In January 2011, Falmouth recorded the highest daily rainfall total on record for anywhere in Tasmania.
    • In February 2011, tropical cyclone Carlos gave 376 mm of rainfall in just 24 hours, the wettest day on record and equal to its February average.
    • In March 2011, Durack Range recorded more than 350 mm in just one day, an event more extreme than 1 in 100 years.

    Related information

  • Temperature trends

    When we combine the Australian land and ocean temperatures, the only summer with warmth comparable to 2012–13 was the strong El Niño year of 1997–98. It has been more than 15 years since Australian temperatures were below the average of 1961–1990.

  • Summer temperature distribution

    Southern Great Barrier Reef
    So what does this mean for tropical cyclones?

    Cyclones today rarely reach southeast Queensland or NSW, preferring the warmer tropics. In the Great Barrier Reef, the average summer sea surface temperature today is about 27.5°C, so about three quarters of days reach the tropical cyclone temperature threshold of 26.5°C, one of the key requirements for cyclone formation.

  • Summer temperature distribution

    Southern Great Barrier Reef

    But, just as we saw for air temperatures, with small increases in the summer average temperature, these cool days become less frequent.

    Related information

    • Kilpatrick, K., G. Podesta, and R. Evans (2001), Overview of the NOAA/NASA advanced very high resolution radiometer Pathfinder algorithm for sea surface temperature and associated matchup database, Journal of Geophysical Research, 106(C5), 9179–9197.
    • Kearns, E. J., J. A. Hanafin, R. H. Evans, P. J. Minnett, and O. B. Brown (2000), An independent assessment of Pathfinder AVHRR sea surface temperature accuracy using the Marine Atmosphere Emitted Radiance Interferometer (MAERI), Bulletin of the American Meteorological Society, 81(7), 1525-1536.
    • Reynolds, R. W., and T. M. Smith (1994), Improved global sea surface temperature analyses using optimum interpolation, Journal of climate, 7(6), 929–948.
  • Summer temperature distribution

    Southern Great Barrier Reef

    With a warming of just 0.7°C, the frequency of cool days has halved relative to the present.

  • Summer temperature distribution

    Southern Great Barrier Reef

    With a warming of 2.1°C, every summer day can be expected to exceed this cyclone threshold, while several days reach temperatures of 32°C, well outside the current range of variability.

    These warm temperatures have other impacts as well – very hot summer sea surface temperatures such as in 1998 and 2002 can cause widespread bleaching of coral, with significant coral death. In WA, an ‘ocean heatwave’ in 2011 was even hot enough to kill fish. Increasing sea surface temperatures make these coral bleaching events much more common.