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166 Cards in this Set
- Front
- Back
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What is a mass movement? |
Anything that falls down |
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What triggers mass movements? (3) |
1.) Earthquakes 2.) Volcanoes 3.) Heavy Rains
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Landslides correlate with |
Mountains |
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Creep |
Slopes that quietly deform and yield to the unrelenting tug of gravity in a slow moving process |
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What must a mass overcome before it fails? (2) |
1.) Friction 2.) Inertia
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Gravitational PE = |
mass x gravitational acceleration x height |
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When something falls, gravitational PE turns into: |
KE
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KE= |
1/2 m v^2 |
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In what ways are slope failures sometimes obvious (4) |
1.) Dipping Layers 2.) Ancient Slip surfaces 3.) Structures within rocks (weak layers, joints) 4.) Influence of water
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What ways does water influence mass movements? (6) |
1.) Loading slopes (increasing weight) 2.) Interactions with clay minerals 3.) Dissolving cements 4.) Dissolving rocks 5.) Subsurface erosion 6.) Pore water pressure increasing, lowers strength and cohesion |
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Daylighted bedding |
Where rock layers are subparellel to the slope or where they dip at angles less than that of the slope, influences mass movements or slippage.
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Rotational Slide |
-Slope with little layers in it, the whole thing decides to slide on a curved plane -downward and outward movement |
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How can you prevent rotational slides? |
-remove hazard (blast it) -insert rock bolts on side -drive piles into slope -drain the water at the top or porous pipes into the slope to drain it |
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Quick Clay or Sensitive Clay failures are formed by: |
-Glaciers creating rock flour that is deposited into seas -Clay and silt sit in a house of cards structure filled with water and sea salts that help it stay as a weak solid -then later lifted above sea level where they become exposed to rain, dissolving much of the sea salts "glue" -Structure becomes unstable, if triggered will turn from a solid to a muddy liquid
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Acoustic Fluidization |
Theorized process where sound waves trapped inside a day, fallen mass lessen internal friction to enable fluid like flow |
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Falls |
-free fall -vertical movement -move as separate blocks
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Flows |
-Flows over a landscape -viscous fluids -turbulence within moving mass
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Slides |
-slide on top of a basal slip surface that may be curved -move as a semi-solid mass -some pre-slide coherence maintained within moving mass |
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Subsides |
-collaspe into void -dominately vertical -move as separate blocks |
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Translational Slides |
Masses move out and down by sliding on the surface of weaknesses such as fractures, clay rich layer, soft rocks slipping off hard rocks etc. -lateral spreading |
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Subsidence can be both: |
slow and catastrophic |
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Subsidence: |
ground surface slowly sinking as fluids are removed below the earth (water or oil) or a sinkhole caused by the collapse of a underground cave |
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Avalanche |
large mass movement of snow |
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What part of Canada are high avalanche activity zones? |
BC and AB |
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Fatalities of avalanches were _______ from 1898-1997. why? |
-Rising -People are going into the mountains more for recreational activities |
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Why is the numbers of fatalities due to avalanches so variable? |
Each year depends on the snowpack, less safe in some winters vs other winters |
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Are fatalities rising or falling in recent years? |
Slightly rising |
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Where do most avalanche fatalities occur in Canada? |
BC
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Where do most avalanche fatalities in the US occur? |
Colorado, Washington -mountainous regions
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What are the 2 types of avalanches? |
1.) Point release 2.) Slab release
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What are the characteristics of a point release? |
-starts from a single point -snow starts sliding down hill, getting broader -rarely cause fatalities -65-100km/hr |
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What are the characteristics of a slab release? |
-layers of snow that are separated by weak layers -when the force on the weak layer gets to strong, the snow on top releases as a slab -slab slides down hill -30-60km/hr, slower but heavier, more deadly |
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Avalanche sizes |
Size 1,3,4,5 -increase in force, run length and mass |
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What are some causes of a weak layer in the snow pack: (3) |
1.) surface hoar 2.) depth hoar 3.) facets |
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Surface hoar: |
-ice crystals that grow on the surface of the snow, create an interlocking structure that is weak |
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Depth hoar: |
-Metamorphic effect of the snow pack -Snow falls and crystals recrystalize over time, become very slippery, so if there are layers near the bottom of the snow pack that are like this, the strength of the layer is quite low |
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Facets |
Form from large temperature gradients, creates a weak layer |
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What is more dangerous, depth hoar or surface hoar? |
Depth hoar -amateurs and professionals can identify a surface hoar, but not so much a depth hoar |
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What angle of slope are most common for a slab release? |
-35-45 degrees |
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What are the two types of snow? |
wet and dry |
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What type of snow and release are the most common for avalanches? |
Dry slab
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What is the most fatal slab thickness? |
41-60 cm
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What side of the mountain is the side that gets the wind? |
Windward, typically SW |
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What is the side opposite of the windward? |
Leeward, NE |
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What kind of slope is in between the leeward and windward slope? |
crossloaded slope
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which side of the mountain sees the most avalanche accidents and why? |
Leeward (67%) -thicker piles of snow on this side, more people travel here for the better snow |
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From 1984-2003, what was the biggest cause of fatalities due to avalanches? |
-backcountry skiing 49% |
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From 2004-2014, what was the biggest cause of fatalities due to avalanches? |
-Snowmobiling 54% -more snowmobilers now then before, and are less prepared to deal with avalanches then the now more educated backcountry |
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Less then a foot down the chances of survival are: |
high |
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most fatalities from avalanches are due to: |
asphexiation |
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1-2 ft down your chances of survival drop by: |
30% |
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6-6.9 ft down, there is a chance of survival IF: |
you have the right equipment and people searching |
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After 30 minutes of being buried, your chances of survival drop by: |
50% |
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Some people don't die from asphyxiation but die from: |
hypothermia hours later |
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what is the most successful way of finding people completely buried by a avalanche? |
-transceivers
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How to prevent avalanches: |
-release them beforehand (explosives) -build a shield -walls -afforestation -deflectors, runout zones |
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Economic costs that influences avalanches: |
cut down trees, released the snow causing and avalanche that damages the land |
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Weather disasters are: |
increasing globally and in Canada |
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Dollar loses from weather related disasters are: |
increasing |
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Most of the earths energy comes from: and is mostly absorbed at: |
-sunlight (heat) -near the equator |
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Why is the max heat absorbed not right at the equator? |
-band of clouds is around the equator, lowers the albedo, leads to a notch or dip in the heating
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Where the heating is maximum, water vapour is _______ dense then the rest of the atmosphere, tends, causes it to __________ and condense to form ___________. |
-less -rise -clouds and the ICTZ |
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intertropical convergence zone: |
where southeast and northeast trade winds converge in a low pressure system causing increased precipitation |
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Ozone layer |
ozone shield refers to a region of Earth's stratosphere that absorbs most of the Sun's ultraviolet (UV) radiation. It contains high concentrations of ozone (O3) relative to other parts of the atmosphere |
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Venus atmospheric circulation |
-hot air rises at the equator, planet trying to even it out -travels north, cool at the poles -sinks backs down, and comes back up at the equator -one big cell, Venus rotates slowly |
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Coriolis Effect |
-Because the Earth rotates, circulating air is deflected. -Instead of circulating in a straight pattern, the air deflects toward the right in the Northern Hemisphere and toward the left in the Southern Hemisphere, resulting in curved paths. |
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Coriolis effect in the Northern Hemisphere deflects air: |
to the right |
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Coriolis effect in the Southern Hemisphere deflects air: |
to the left |
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Hadley Cell |
-Thermally driven atmospheric circulation pattern -Hot air rises at the equator, divides and flows towards both poles -Then the air descends to the surface at about 30 degrees North and 30 degrees South |
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Ferrel Cell |
30-60 Degrees N & S |
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Polar Cell |
60-90 Degrees N & S
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Velocity of earth at the equator |
1600 km/hr |
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Low pressure System is caused by: |
-water vapour, less dense then atmosphere, rises up, air around it blowing in all directions |
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In the Northern Hemisphere, air coming into a low pressure system is bending to the |
right Counter-clockwise |
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In the southern hemisphere, air coming into a low pressure system is bending to the |
left clockwise |
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Low pressure system conditions are: |
Clouds and precipitation |
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High pressure systems are caused by: |
Air blowing outwards from it, cool air sinking down |
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Southern hemisphere, air coming into a high pressure system is bending to the |
left Counterclockwise |
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In the Northern hemisphere, air coming into a High pressure system is bending to the |
right clockwise |
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Conditions in a high pressure system |
no clouds and sun |
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Low pressure and high pressure systems are also called |
cyclones and anticyclones |
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Jet Streams |
Narrow bands of high velocity wins that flow at high altitudes |
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Which way do Jet streams flow? |
West to East |
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2 Jet streams: |
Polar and Subtropical Jet Streams |
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Which Jet stream is faster? |
Polar (600km/hr) |
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What are the 2 types of ocean currents |
Surface and deep |
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Ocean currents velocity: |
1 m/s |
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Ocean currents move slowly because it carries more: |
Heat
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What causes currents to flow in different directions? |
Continents getting in the way |
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When the polar hood is tipped towards Asia, we experience a: |
warmer winter! |
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Why don't the Eastern States have a desert? |
Gets warm air from the gulf of mexico, giving it lots of moisture |
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The planet switches between what conditions? |
Ice house and Greenhouse |
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Ice house: |
Large sheets of ice cover the poles, earth is a big colder then the long term average
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Over time there has been a ____________ in atmospheric CO2 |
Decline |
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25,000 years ago, calgary was: |
buried under km's of Glacier |
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25,000 years ago the global ocean level was: |
90 m lower then it is now |
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What causes the climate of the earth to change? |
Milankovitch cycles |
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Eccentricity |
-The scale of the earths elliptical orbit of the sun -More elliptical=less solar radiation recieved
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Shape of Orbit cycle: |
every 100,000 years |
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Tilt |
Spin axis of the earth tilt away from the Orbital plane -varies from 24.5-21.5 degrees -greater tilt=more seasonal extremes |
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Tilt cycle:
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41,000 years |
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Wobble |
where the spin axis is pointed -less effect then tilt |
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wobble cycle: |
19-23,000 years |
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Temperature and CO2 relationship |
lower temp: less CO2 |
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During the last 10,000 years the average global temperature varies by: |
6 degrees |
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Rapid switches in climate system is called: |
"tipping points" |
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Geological examples of the earths systems that switch: |
1.) Snowball Earth ~ 700 million years ago
2.) Cretacous "Ocean Anoxic Event" -much of the worlds ocean, now oxic, stopped being mixed and became anoxic, no one nos why
3.) Paleocene-Eocene Thermal Maximum
4.) Dansgaard-Oescheger evens during the last ice age |
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Climate of the last 1000 years temp variation: |
1.5 degrees |
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Little Ice Age: |
Glaciers were advancing -have been decreasing since |
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Sunspots |
Area of magnetic storms that are cooler then most of it -come and go on a regular cycle, 23 yrs |
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How bright is the sun? |
1365-1367 w/m^2 |
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When did sunspots disappear? |
During the Maunder minimum (1650-1730) |
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El Nino Conditions |
-Wind and Ocean currents reverse -Winds flow east off the Pacific, cause huge rain storms over the South American deserts |
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Drought: |
A rainfall or precipitation deficit sufficient to affect agriculture -50% reduction over 3 months |
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The Palliser Triangle |
-region of the prairies thats to dry to grow crops |
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Water limits in AB and SK affected: |
The aqueduct built for irrigation of crops over the prairies, now sits empty for theres not enough water |
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What causes droughts in Canada and Central USA? |
-High pressure ridge getting stuck over these areas
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What causes famine in Ethiopia? |
If the ICTZ doesn't shift upwards in the summer time, doesn't deliver the monsoon season and famine occurs |
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Sahel |
Area in-between regions with lots of rain (NE Africa) to region of none (sahara) |
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Last 40 Years of Sahel rainfall pattern: |
-mostly a constant dry phase, famine conditions |
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What do you need to have thunderstorms? |
Humidity in the air |
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How is a thunderstorm formed? |
-When the air is humid enough, air rises and cools off -Some of the water vapour condenses and releases heat -It is now warmer which makes it rise even more (positive feedback loop)
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Why does a thunderstorm usually stop at night? |
Air cools at night, not enough energy to keep it going
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What is the energy that drives a thunderstorm? |
Latent heat of condensation: 2.26x10^6 J/kg |
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What temp can hold a great deal of water vapour and how much? |
-30-35 degrees -3 g of H2O / kg of air |
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Where in Canada gets the most thunderstorms? |
Southern Ontario |
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Downbursts: |
-When Thunderstorm is sucking in wind, pushes a lot of air up quickly, rain comes back down around it, accelerates the air around it -When they hit the ground, they turn sideways and can create very strong winds (F1/F2) -Also called windshear
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Derechos: |
"straight ahead winds" -A line of thunderstorms, formed at a weather front, add up winds into the same direction |
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Hailstones have a: |
layered stratigraphy
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Hail stones increase in size due to: |
how many cycles through the storm it goes through -faster updrafts: bigger hail stones |
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Hail capital of Canada: |
Alberta, 5 days/year in Red Deer |
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Hail doesn't occur where thunderstorms are most common, but where |
thunderstorms have enough power |
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Tornadoes are almost always associated with: |
Thunderstorms |
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What do tornadoes need to form? |
-windshear (downbursts) -caused by winds going one way and different winds going another |
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Mesocyclone: |
rotating thunderstorm |
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USA tornado capital: |
Oklahoma, Texas area -Mid altitude winds, jet streams, and wind from the gulf are all flowing in different directions |
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Who has the highest tornado fatalities and why? |
Bangladesh, high population density |
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How can you tell a tornado is going to form? |
Wall cloud |
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Whats the series of events you experience before a tornado: |
1.) light rain 2.) heavy rain 3.) light hail 4.) heavy hail 5.) wall cloud 6.) tornado
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US tornado fatalities are: |
decreasing, becoming more stable, easier to predict with technology |
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Tornadoes occur in what months? |
Most in the summer months May July June August |
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Why do the fatalities peak in April? |
People forget they need to treat Tornadoes with respect |
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wind force is proportional to: |
velocity^2 |
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Fujita scale increases with |
windspeed |
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What percent of tornadoes are violent (f4/f5) |
1% |
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what percent of fatalities are due to violent tornadoes? |
67% |
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What is the most deadly location to be in a tornado? |
Mobile Home |
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Tornadoes path is: |
Northeasterly |
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Where has the most amount of tornadoes in Canada? |
Southern Ontario (10+ per year) Also high in the prairies (5-7.5 per year) |
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Deadliest tornado in Canada |
Regina SK 1912 28 fatalities F4 |
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Safest place to go and what to do if theres no wear to go? |
-underground -lie face down on the ground |
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Blizzard characteristic: |
zero visibility |
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City with largest amount of blizzard hours per year: |
St. Johns 46 |
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Why do cities along the east coast have a high amount of blizzard hours: |
storms coming of the North Atlantic |
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What is the windchill factor where frostbite occurs: |
2280 w/m^2 |
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Blizzards are most dangerous when: |
they last for several hours of days |
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What is required to have a blizzard: |
Dry Snow and wind -doesnt need to be snowing |
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How do you get freezing rain? |
-rain comes down from hot air (from the gulf) into cooler air, becomes SUPER COOLED. -As soon as it hits a surface, it turns to ice and will stick to anything
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Warm air above cold air is called: |
Atmospheric inversion |
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What happens when super cooled air hits something? |
It lowers the Activation energy, allowing it to freeze |
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Where in Canada experiences the most freezing rain? |
St. Johns, 148 hrs/year |
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Lightening causes how many fatalities in Canada per year: |
10-15 |
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How does lightening form? |
Charge separation caused by friction between drops of rain and air -Bottom of storm has neg charge, and ground has induced positive charge, when they connect they have a conductive zone, that creates a bright flash as charges exchange |
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Heat waves can be very: |
deadly
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Heat waves usually affect the: |
elderly |
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Why are heat waves so deadly? |
it doesn't cool off at night, so theres no time for the body to recover from a hot day, no time to gain back energy |
