Ice on the Land Flashcards
What is the El Nino effect?
a periodic blip in the usual climatic characteristics
caused by a short term reduction in the intensity of the cold ocean current that normally exists off the west coast of South America
resulting in unusual patterns of temp and rainfall and can lead to floods.
What is the period we are in now called?
Holocene Period
What was the last ice age called?
Pleistocene Period
2 million years
How big is an ice sheet?
over 50,000 km squared
How big is an ice cap?
under 50,000 km squared
What is the world’s largest ice sheet?
Antarctica
What is the balance between accumulation and ablation called?
glacial budget
What is a positive glacial budget?
when accumulation dominates over ablation
What is an example of a glacier (retreat since the 19th century)?
Athabasca Glacier
Example of weathering?
Freeze Thaw
Examples of erosion?
Abrasion - sand papering effect
Plucking
How do glaciers move?
Rotational Slip - melted water helps to lubricate the glacier and in a curved hollow rotational slip happens
= slippage of ice along curved surface
Sheer weight of the ice cause individual crystals to deform in a plastic like way.
Why does deposition occur?
mostly when the ice melts
mostly at the snout
What is bulldozing?
an example of transportation
the pushing of deposited material at the snout of the glacier as it advances
What is a hummock?
a small area of raised ground, rather like a large molehill
How is a truncated spur formed?
an eroded interlocking spur characterised by having a very steep cliff
What is moraine?
material transported then deposited by the ice
Where is ground moraine?
material underneath the glacier
Where is lateral moraine?
material at the sides of the glacier
Where is medial moraine?
material running down the centre of the glacier
when two lateral moraines combine
Where is terminal moraine?
material piled up at the end of the glacier showing the extent of the glacier’s advance
What are drumlins?
smooth, egg shaped hills about 10 m high few 100 m in length stoss and lee end lee end faces down the valley
What is an avalanche?
masses of snow and ice moving rapidly usually in a mountainous environment
What is a loose snow avalanche?
usually starts from one point
involves loose powdery snow
What is a slab avalanche?
slab of ice and snow
shears away from main ice pack
(more deadly)
What are the causes of avalanches?
heavy snowfall steep slopes heavy snowfall temp rise human factors (skiing off-piste) tree removal
Case study of an alpine area?
Chamonix
how to manage avalanches?
- fences
- walls
- planting trees
- mounds of snow (breaking)
