NATURAL DISASTERS 3WILD WEATHER Deadly weather – cyclones, severe storms, storm surges, tornadoes, floods and extreme temperatures – often strikes with little warning time. In Australia, severe storms occur more often than any other natural hazard. InTRODUCTION World faces growing Two case studies … THE second strongest IN Victoria, a strong La but floodwaters gradually spread wild weather threat La Nina event on record Nina influence and warm downstream until much of Victoria 1 since 1918 gave much of 2 ocean temperatures around looked like an inland sea. Flooding RIPPLE of air over warm, blue sea, a puff of cloud in the sky. Australia an unusual rainy season at Australia helped trigger record affected 75 towns. These major, Innocent enough, but is it the birth of a tropical cyclone that the end of 2010 and in early 2011. humidity and heavy rain at the end riverine floods were some of the A may kill hundreds, displace thousands and cause billions of Large areas of Queensland were of 2010. In January, more rain gave most extensive seen in Victoria. The dollars in property damage? Around the world, more than 1 billion flooded, including parts of Brisbane, the Campaspe, Lodden, Avoca SES answered thousands of calls people have lost their lives from weather and climate-related events and more than 78 per cent of the and Wimmera river catchments for help. Some floodwaters were over the past 60 years. They are the only category of natural disaster state was declared a disaster area. record flood peaks. After initial local 20 kilometres wide and damage has that is increasing in force and the number of deaths and amount Much of Australia was soaked. flash flooding, the weather cleared been estimated at $1.3 billion. Two “big wets” in 2011 show of destruction they cause. A leading natural disaster database the difference between flash and (NatCatService) shows that weather-related catastrophes have more riverine flooding. Flash floods can than tripled over the past 30 years. In China alone, weather-related occur almost anywhere. Bursts 1 disasters have quadrupled since 1980. of heavy rain can be too much for Also, a report by the Geneva-based Internal Displacement drainage systems. On January 10, Monitoring Centre (IDMC) reveals the large number of people forced 2011, Toowoomba, in south-east from their homes because of sudden, natural disasters – 42 million Queensland, was struck by intense in 2010, 17 million in 2009 and 36 million in 2008. More than 90 per storms that dumped as much as cent of this displacement was because of weather-related disasters, 60 millimetres of rain an hour. This followed months of wet weather; the mostly floods and storms. ground was already saturated. Three Why are these disasters getting worse? Many experts are pointing natural creeks, which once flowed to climate change, with rising sea and land temperatures. They warn through the city, had been narrowed that record-breaking weather will only increase as our human impact and altered through development. on the environment grows. These streams swelled into raging “The intensity and frequency of extreme weather events are torrents that tore through the centre increasing, and this trend is set only to continue. With all probability, of town, picking up cars like toys. the number of those affected and displaced will rise as human- A mother and her 13-year-old son induced climate change comes into full force,” says the IDMC. died after making an emergency call for help. It was just one of the tragic And why do people in poorer countries suffer most? The stories to emerge from the disaster. International Disasters Database EM-DAT records that between Toowoomba sits on an escarpment 2 1991 and 2005, more than 90 per cent of natural-disaster deaths on the Great Dividing Range west of and 98 per cent of people affected by natural disasters were from Brisbane, about 700 metres above developing countries. sea level. Some of the water, as well Consider these examples. Cyclone Nargis, which struck Burma in as heavy rain falling on the slopes of May, 2008, was one of the deadliest storms in history. About 140,000 the range, quickly filled the creeks people died. High winds and a powerful storm surge destroyed running down to Lockyer Valley 700,000 homes in the coastal delta, killed three quarters of the below. The speed of flash floods livestock, sank half the fishing fleet and flooded rice paddies with salt here caught residents by surprise. Surging waters pushed water tanks, water. Burma’s military rulers were highly secretive about the damage, machinery, vehicles and buildings forcing international ships bringing aid to wait offshore for weeks. along roads and through paddocks, Record-breaking summer monsoon rains triggered massive sucked furniture and people from floods and landslides in Pakistan in July, 2010. With 1760 killed, it homes and destroyed buildings, was the world’s fourth deadliest natural disaster that year. A fifth of roads, rail lines and livestock. In all, the country was underwater for weeks, and 11 million people were 17 people died and three are still forced to leave their homes, with hundreds of thousands still living in missing. makeshift camps months later. The damage bill was $US9.5 billion, a heavy burden for an emerging economy. Flooding historically has been the worst of Australia’s natural disasters. (Although it is not well recognised, heat waves cause A deadly mix of factors the most deaths.) In the past two years, a strong La Nina, plus the highest sea temperatures measured off the Queensland coast, ISASTROUS weather does contributed to unusually extreme weather – including a category not always arrive in the 5 cyclone (Yasi) in Queensland, plus heavy rain and floods in Dform of a severe cyclone. Queensland, Victoria and Western Australia. The weather, which swamped the Philippines island of Mindanao in December 2011, was a tropical TROPICAL SEA SURFACE TEmpERATURE WAS THE HIGHEST ON storm with winds of about 60 km/h RECORD FOR THE SECOND HALF OF 2010 and gusting to 100 km/h, but never reaching typhoon status. However, a number of factors combined to make this a major natural disaster. The region is mountainous, and when Tropical Storm Washi, or “Sendong”, dumped heavy rain – up to 200 millimetres over 12 hours – water gushed down hillsides, overwhelming rivers and flooding communities on the coast. Rescue operations at Cagayan De Oro, Philippines. More than 1000 people died and 1582 were injured. Many people heightening the risk of disease. or lack of awareness, may have were washed away by flash-flooding Most fatalities were in two cities, been another factor in the disaster n Highest on record while they were asleep. Others were Cagayan De Oro and Iligan City, because Mindanao Island is not n Very much above average buried in landslides. although hundreds of those killed usually in the path of the 20 or so n Above average Deforestation had denuded hills, were in slum settlements along the typhoons that hit the Philippines n Average so rain water ran off quickly. River coast. Nearly 340,000 people were each year. n Below average n Very much below average systems in which river beds were affected by the disaster, with more Washi began on December 13 as n Lowest on record already silted, filled and overflowed. than 88,000 displaced and moved a tropical depression and intensified Families were swept out to sea to makeshift evacuation centres. to a tropical storm. Sep-Dec 2010, rainfall deciles (used to rank historic climate data). from coastal towns, and corpses More than 10,000 houses were See: earthobservatory.nasa.gov Courtesy National Climate Centre / Australian Bureau of Meteorology remained unburied for many days, damaged or destroyed. Surprise, /NaturalHazards/view.php?id=76702 NASA’s Aqua satellite shows Cyclone Yasi approaching Some of the worst the Queensland coastline Fact file on February 2, 2011. One of CYCLONE MAHINA, MARCH 1899, NORTH QUEENSLAND Australia’s biggest cyclones It was responsible for more deaths than any other natural disaster in Australia’s in a century, it devastated history. A category 5 cyclone, it killed about 400 people. No reliable records of wind speed exist, but barometer readings suggest central pressure was several towns and cut power 914 hPa (hectopascals), one of the most powerful to reach Australia. Central to 175,000 people. pressure is one indication of cyclone intensity; the lower the pressure, the Photo: JEff SchmaLTZ / NASA greater the intensity. (Cyclone Orson, 1989, 905 hPa, Cyclone Tracy 950 hPa). CYCLONE TRACY, DECEMBER 1974, DARWIN Tracy was a compact storm, just 50 kilometres wide but a powerful, category 4 cyclone. It swung over the Arafura Sea to hit a complacent Darwin early on Christmas Day. Fierce winds (217 km/h before the recorder was destroyed) How tropical cyclones Tornadoes in Victoria? We’ve seen a few and the inadequate design of many buildings meant the city was virtually destroyed. The storm killed 49 people in town and 16 more at sea. In a build their fury Tornadoes are violent, rotating A lightning storm over Sydney. Flash flooding in Melbourne. Cyclone Yasi’s destructive path. population of 43,000, 25,000 were left homeless. columns of air that touch down OME of the world’s wildest mass starts to rotate around a low- to earth in the well-recognised n Lightning causes 5 to 10 deaths Victoria are susceptible to flooding more than 2100 deaths in Australia weather comes in the form pressure centre. The rising, moist funnel shape from a storm cloud. and more than 100 injuries in at least once in a 100-year period. since 1839.