PART B: - FLOODS ARE A NATURAL CLIMATE PHENOMENON. HOWEVER, THEIR PHYSICAL IMPACTS CAN BE NATURAL DISASTERS

Question 1

What are the FIVE causes of floods

Answer 1

Heavy rainfall: This is the most common cause of floods in Australia, and can occur due to a range of weather events such as tropical cyclones, monsoonal systems, thunderstorms, and other weather events.
King Tide: A ‘king tide’ refers to an abnormally high tide that is a natural and predictable occurrence during the tidal cycle. King tides can exacerbate riverine flooding, particularly in coastal towns situated along rivers. During such flooding, if a king tide coincides with the event, the floodwater is less likely to drain into the sea, leading to a more extensive and severe flooding of the town.
Storm surges: This is a coastal flooding phenomenon that occurs when strong winds and low pressure cause a rise in sea level, resulting in water surging onto the coast. Storm surges can be caused by tropical cyclones and other severe weather events.
Snowmelt: The process of snowmelt involves the gradual release of water stored in snow, as temperatures rise. However, in cases where warming occurs rapidly, snow can melt quickly, leading to excessive water release. This can result in riverine flooding, as the downstream channels may not be able to handle the sudden increase in water volume.
Dam release: In cases where a dam is nearing its capacity, dam operators may release water, which can result in flooding. To prevent such incidents, we collaborate closely with dam operators during floods, providing them with up-to-date weather information. They then utilize this information to regulate their dams, minimizing the potential impact on communities downstream.

Question 2

What is La Nina?

Answer 2

• La Niña is a weather phenomenon in the Pacific Ocean with cooler sea surface temperatures
• It causes stronger trade winds, pushing warm water westward and cooler water in the east.
• La Niña brings increased rainfall and cooler temperatures.
• The Bureau of Meteorology monitors La Niña to provide forecasts, warnings, and study its impacts.

Question 3

Investigate how human activities, including the use of fossil fuels, contribute to the
frequency and magnitude of floods.

Answer 3

• Human activities like land clearing, urbanization, and dam construction can disrupt natural drainage patterns, raising flood risks.
• Deforestation diminishes forests’ ability to absorb and store water, causing increased runoff and flooding.
• Urbanization leads to more impervious surfaces, like concrete, accelerating runoff and reducing water absorption into the ground.
• Fossil fuel usage contributes to climate change, intensifying the effects of extreme weather events like floods.
• Human-caused climate change amplifies extreme weather events, resulting in more frequent and severe flooding.