El Nino
What is it?
El Nino is the normal circulation pattern in the Pacific Ocean which brings rain to Australia. In an El Nino year the circulation reverses and South America receives the rain while Australia remains dry. In El Nino the hot water gets pushed towards South America and becomes a warm wet low pressure system.
What places have been affected by El Nino in Australia?
Australia’s climate is highly variable from year to year. For example, 1998 to 2001 were all very wet years across northern and central Australia, with some parts receiving more than double their average rainfall over the four-year period. In contrast, 2002 and early 2003 saw one of the worst droughts in Australia’s history. In eastern Victoria alone, the drought led to approximately 1.2 million hectares of land, including 41 houses and 9000 livestock, being burnt over a span of 59 days starting in January 2003. This was the largest fire event in Victoria since 1939. Other states have also been affected by Droughts, like in 1902 Queensland suffered a major drought which lasted more than 10 years. These are some of the affected areas in which El Nino has taken and destroyed.
How are the El Nino Disasters formed?
Much of the variability in Australia’s climate is connected with the atmospheric phenomenon called the Southern Oscillation, a major see-saw of air pressure and rainfall patterns between the Australian/Indonesian region and the eastern Pacific. The Southern Oscillation is measured by a simple index, the Southern Oscillation Index (SOI), which can also be related to specific changes in the temperature of the underlying ocean, commonly referred to as El Nino and La Nina events.
Rural productivity, especially in Queensland and New South Wales, responds significantly to the behaviour of the Southern Oscillation. This is how El Nino disasters are formed.
El Nino-Federation Drought
- Began in the mid 1890s and reached its devastating climax in late 1901 and 1902.
- Animal Stock dropped
- Suffered a major drought
- Wheat crop was “all but lost”, Darling River was dry at Bourke for over a year
- Concerns about water supply
- Failure in wheat crop
- Areas affected include: Queensland, New South Wales and the Northern Territory
La Nina-
La Niña is a joined ocean-atmosphere phenomenon that is the counterpart of El Niño as part of the broader El Niño-Southern Oscillation climate pattern. During a period of La Niña, the sea surface temperature across the equatorial Eastern Central Pacific Ocean will be lower than normal by 3–5 °C. In the United States, an episode of La Niña is distinct as a period of at least 5 months of La Niña conditions.
Effects of La Nina
The results of La Niña are mostly the opposite of those of El Niño, for example, El Niño would cause a wet period in the Midwestern U.S., while La Niña would typically cause a dry period in this area. At the other side of the Pacific La Niña can cause heavy rains. For India, an El Niño is often a cause for concern because of its adverse impact on the south-west downpour; this happened in 2009. A La Niña, on the other hand, is often beneficial for the downpour because it would increase the chance of rain and precipitation
La Nina- Queensland Floods
- La Nina helped create the 2010/11 Queensland Floods
- 35 were confirmed dead and 9 missing
- Estimated $30 billion in damage
- The Queensland Floods covered most of Queensland including its capital city Brisbane.
- Much of central and southern Queensland including Brisbane, Rockhampton, Emerald, Bundaberg, Dalby, Toowoomba, and Ipswich were the affected areas from the floods
- Queensland Reconstruction Authority was set up to help with the relief of the floods
- More than 55,000 volunteers gave their time and money to help with the clean up of Queensland's affected areas
- The Australian Defense Force set up Operation Queensland Flood Assist and About 35 State Emergency Service personnel from New South Wales and 20 personnel from Victoria were deployed to provide relief to exhausted staff and volunteers
View el Nino in a larger map
View La Nina in a larger map
View El Nino - Federation Drought in a larger map
View La Nina- 2010/11 Queensland Floods in a larger map
