Australia’s Fire and Heat Season Is Off to a Grim Start

Parts of northeast Australia have been assaulted by all-time record heat and unprecedented fire risk even before the austral summer gets under way. As of Thursday morning local time, more than 130 bushfires had scorched the forested strip between Australia’s vast outback and the coast of Queensland, with some fires racing toward the coast itself. Only a few homes were confirmed as destroyed on Thursday, although it was still too early for damage assessment in many areas, noted weather.com.

Fire Danger Ratings have reached Catastrophic for the first time in #Queensland due to the combination of a very dry, hot airmass and strong, gusty westerly winds. Follow the advice of @QldFES during these extremely challenging fire weather conditions: https://t.co/rfYMgjkWoL pic.twitter.com/tRqG2VnqYA

— Bureau of Meteorology, Queensland (@BOM_Qld) November 28, 2018

The six-category fire danger rating hit “Catastrophic” over parts of southern Queensland on Wednesday, the first time any location in the state has ever earned that most-dire rating. The fire threat dropped on Thursday and is predicted to lessen further toward this weekend, though it will remain very high over large parts of the state. Extreme heat is predicted to expand next week across northeast Australia.

Severe to Extreme Heatwave conditions currently remain focused on north #Queensland but next week will see the heatwave spread across northern Australia extending into #SEQ and #Brisbane: https://t.co/L9UlivU8HP See @qldhealthnews for tips on staying healthy in the heat pic.twitter.com/vTVdG4lH3V

— Bureau of Meteorology, Queensland (@BOM_Qld) November 29, 2018

Perennial fires amid a changing climate

Bushfires are a normal part of Australian climate. They often rage across vast stretches of the thinly populated Outback. Australia’s bushfires pose the greatest threat to life and property when they rip across the more heavily vegetated and populated areas of southeast and far eastern Australia, and especially when they hit communities on the wildland-urban interface. Here, they can be every bit as deadly and destructive as the worst California wildfires.

According to Geoscience Australia, major bushfires from 1967 to 2013 caused 433 deaths, 8000 injuries, and some $4.7 billion in damage (2013 Australian dollars, roughly equal to $5 billion in 2018 USD). If this were scaled up to the U.S. population, it would represent more than 5000 deaths and 100,000 injuries.

Since southern Queenland gets much of its moisture during summer, its fire season tends to be most intense from spring into early summer, so this week’s fires are on target in terms of seasonality. One thing helping to make these fires so fierce and widespread is an intense drought that’s parched the landscape in recent months across much of eastern Australia. In turn, this year's drought falls on the heels of six abnormally dry years across the region.

A special report (see PDF) from the nation’s Bureau of Meteorology (BOM) concluded that “the recent dry conditions in eastern Australia have few precedents for their combination of extent and duration.” In many locations, the six-year dryness is comparable only to multi-year droughts in the late 1960s and from the mid-1920s to mid-1930s.

Insurance broker Aon puts the cost of Australia's 2018 drought thus far at $1.2 billion. According to EM-DAT, the international disaster database, only three other droughts have caused more damage in Australia: 1981 - 1982 ($6 billion 1982 dollars), 2002 ($2 billion 2002 dollars), and 1993 - 1995 ($1.5 billion 1995 dollars).

Figure 1. A kangaroo hops across the road outside the town of Booligal in western New South Wales on September 27, 2018. From abandoned baby kangaroos to wallabies being blinded by the sun and koalas having to go walkabout to look for eucalyptus leaves, Australia's exotic wild animals are struggling to adapt to a crippling drought. Image credit: Peter Parks/AFP/Getty Images.

High temperatures are another factor making the fire threat worse. Research has shown that droughts are increasingly accompanied by unusual warmth in California, making for a surge in “hot droughts” that’s consistent with a human-warmed climate. Much the same may be going on in Australia. Average spring temperatures across the nation climbed by about 1.6°F between 1960 and 2013, according to Climate Central. Relative humidities in spring are also dropping. For the nation as a whole, the amount of precipitable water (moisture in the atmosphere) was the lowest on record this year for the April-to-September period.

The heat and dryness this past winter and spring across eastern Australia was triggered in part by cool sea surface temperatures across the eastern tropical Indian Ocean, according to BOM. Meanwhile, conditions over the tropical Pacific have been pushing toward an El Niño event, which tends to bring warmer- and drier-than-average weather to Australia.

Figure 2. Chance of exceeding the typical daily high temperature when averaged across the three months of austral summer (December to February). Image credit: BOM.

All-time record heat along the Queensland coast

A number of locations on and near the middle and north Queensland coast, including some of the region’s largest towns and cities, have smashed longstanding records for the highest temperature ever recorded, in some cases by more than 4°F. These include:

Monday 11/26
Cairns Airport:  42.6°C (108.7°F), old record 40.5°C on Dec. 20, 1995
Cairns Racecourse: 43.6°C (110.5°F), hottest temperature on record for Cairns
Proserpine Airport:  44.9°C (112.8°F), old record 42.9°C on Dec. 20, 1995
Mackay Airport:  39.7°C (103.5°F), old record 38.5°C on Oct. 11, 1955
Mackay Racecourse: 40.7°C (105.3°F), hottest temperature on record for Mackay
Mareeba:  39.8°C (103.6°F), old record 39.0°C on Nov. 3, 2000

Tuesday 11/27
Cooktown:  43.9°C (111°F), old record 41.4°C on Nov. 23, 2008
South Johnstone:  42.2°C (108°F), old record 40.4°C on Dec. 29, 1971

Wednesday 11/28
Alva Beach:  40.5°C (104.9°F) old record 38.7°C on Dec. 18, 2005
Yeppoon (The Esplanade):  42.2°C (108°F), old record 40.5°C on Dec. 23, 1995

New risk for coral reefs over the coming months

The Queensland heat wave is pumping warmth into the offshore waters, which is bad news for Australia’s Great Barrier Reef. Experts are already raising concerns about the reef’s fate this summer. The reef was ravaged by destructive bleaching in 2016 and 2017, but spared in early 2018 in part by cooler waters upwelled by Tropical Cyclone Winston. Warmer water makes bleaching events more likely.

Terry Hughes, who directs the Australian Research Council’s Centre of Excellence for Coral Reef Studies at James Cook University, said in a tweet: “The bleaching forecasts are trending upwards, but it's far too early to tell this far out. We'll have a better idea by the end of January.”

This is terrifying. An early summer heatwave breaks all records, lifting the chances of another episode of coral mortality on the #greatBarrierReef next Feb/March. https://t.co/NQkoKhGW5P

— Terry Hughes (@ProfTerryHughes) November 26, 2018

El Niño is often associated with global-scale mass bleaching events, as it spreads warm surface water across large parts of the tropical Pacific. In the Great Barrier Reef, it is the sunny, hot weather patterns that become more common during El Niño—rather than the oceanic warming directly caused by El Niño—that appears to trigger the worst bleaching episodes, according to a 2017 study led by Hamish McGowan (University of Queensland). On top of these year-to-year factors, long-term ocean warming driven by human-produced climate change is adding to the existential threat to coral reefs worldwide.

Figure 3. NOAA’s Coral Reef Watch alert system has much of the western tropical Pacific in its “watch” category, with a small area near the Marshall Islands in the most dire category, Alert Level 2. Image credit: NOAA.

The big wet is here #bigwet18 #sydneystorm #pottspoint pic.twitter.com/wLdZ7seHh7

— Ross Ness (@RossNess) November 27, 2018

Spectacular storm in Sydney

The same late-spring upper-level storm that drove hot, dry winds from the interior onto the Queensland coast also triggered intense thunderstorms over the Sydney area during the Wednesday morning rush hour, causing widespread flash floods. Two deaths were reported, according to weather.com. “The conditions we are experiencing [on Wednesday] are some of the worst I’ve ever seen,” New South Wales Police Assistant Commissioner Michael Corboy told the Morning Herald.

Sydney’s Observatory Hill picked up 84.6 mm (3.33”) of rain between 5:20 and 7:00 am Wednesday, and a total for the morning of 118 mm (4.65”). That's about 40% above the typical rainfall for the entire month of November, the Sydney Morning Herald reported.