What can you observe from the picture? When was it taken?
That it was a flood and that everything is flooded with water. It was very deep.
That there is no way of transport, nowhere to go, everyone is suck in one area
and business are shut down. The water in unclean and it also looks very windy.
Where do you think Miss Burtenshaw is? When?
Miss Burtenshaw is in Forbes in New south wales in 2012.
Define a flood in your own words.
A flood happens when water overflows or soaks land that is normally dry. There
is a few places earth where people don’t need to be concerned about feeling.
Floods take hours or even days to develop, giving residents time to prepare or
evacuate. Sometime, floods develop quickly and with little warning.
What are the three types of floods?
1. Slow onset floods
2. Rapid onset floods
3. Flash floods
What is a flood plain?
A flood plain is a low plain adjacent to a river that
is formed chiefly of river sediment and is subject
to flooding.
What is alluvium? (Hint: Check your textbook for a definition)
A deposit of clay, silt, sand, and gravel left by flowing streams in a river valley or delta, typically
producing fertile soil.
If you need to re-write a definition of La Nina, write it here.
A cooling of the surface water of the eastern and central Pacific Ocean, occurring
somewhat less frequently than El Niño events but causing similar, generally
opposite disruptions to global weather patterns. La Niña conditions occur when
the Pacific trade winds blow more strongly than usual, pushing the sun-warmed
surface water farther west and increasing the upwelling of cold water in the
eastern regions.
Task: Answer questions 1-4 on page 75. Upload via edmodo, or write on this
worksheet or in your book to submit at a later date.
1. Define a flood and describe the three main types of floods.
Slow onset Floods-A slow flood normally builds over a period of time and
is caused by water overflowing from a dam. This kind of flood gets its
time to get there and also stays on for a long period of time. People have
time normally to evacuate, which means that there is more damage to
property than to life.
Rapid onset Floods- Rapid-Onset Floods last for a relatively shorter
period, they usually last for one or two days only. Although this kind of
flood lasts for a shorter period, it can cause more damages and pose a
greater risk to life and property as people usually have less time to take
preventative action during rapid-onset floods.
Flash Floods- Flash Floods may occur within minutes or a few hours after
heavy rainfall, tropical storm, failure of dams or levees or releases of ice
jams. And it causes the greatest damages to society.
2. Explain why floods occur on flood plains and deltas.
Floods occur on flood plains and deltas because both would been have
flooded in the past due to a river or steam overflowing its banks or rivers
and is subject to periodic flooding.
3. Describe the actions that can be taken by communities to reduce the
impacts of floods.
The actions that can be done by communities to reduce the impacts of
floods is to install rock berms, rock rip-raps, sandbags, maintaining
normal slopes with vegetation or application of soil cements on steeper
slopes.
4. What is LA Nina? Why are floods often associated with La Nina?
A cooling of the surface water of the eastern and central Pacific Ocean, occurring
somewhat less frequently than El Niño events but causing similar, generally
opposite disruptions to global weather patterns. La Niña conditions occur when
the Pacific trade winds blow more strongly than usual, pushing the sun-warmed
surface water farther west and increasing the upwelling of cold water in the
eastern regions.
Floods often associated with La Nina because La Nina is associated with strong
wet weather patterns.
EXT: Answer question 6 (b), then find a weather map for recent floods in
Australia. What can you observe?
Weather system responsible for this cloud mass and heavy rainfall is eastward
moving cold fronts. The weather system located on the weather map is in New
South Wales, Victoria and Tasmania.
What causes floods?
A flood occurs whenever water in excess of the expected amount comes into an
area. Complex weather patterns can increase rainfall, which leads to flooding. A
river naturally accommodates a certain volume - - it has been formed over
millennia to handle that amount of water. If an unexpected rush of water arrives
in the waterway, the water exceeds the walls of the channel and the surrounding
area floods. Another way rainfall can cause flooding is if precipitation falls faster
than the ground can absorb it.
Why might a cold front cause flooding?
Because Cold fronts have a steep slope which causes air to be forced upward a
long its leading edge, meaning sometimes a band of shower or thunderstorms
may line up a long the cold front often resulting in flood due to the heavy shoers.
How does flooding impact Australian communities? How much does it cost
annually?
Flooding impacts communities and indivials resulting in a lot of damage costing
about $377 million per years. The houses, building, transport, loss of jobs, crop
damage and many more.