·      75% of death destruction of natural disasters = tornadoes, hurricanes and lightening 

·      Heat, moisture

·      Water = H20 à bonded at 105 degrees bond angle to oxygen

·      Chemistry neutral 

Top Ten Reasons Water is SO COOL:

1.  Bipolar -- weak sign on both sides  -- can pull things apart -- surround othe element / ion à satirize

1. Universal solvent (highest dielectric constant)
2. Highest latent heat of vaporization
3. Highest latent heat of fusion -When you take water from a vapor to a liquid you release the calories. 
4.  Exists in three phases on Earth -Nothing else exists in huge quantities in all three phases.  
5. Solid less dense than liquid -Water is the only substance that expands when 10% when it turns into a solid. 
6. Highest heat capacity
7. Highest surface tension -Can’t poke through water.
8. Highest heat conduction - Air is an insulator. 
9. The reason life is possible.  

the sun 

(an exogenic cycle) 

the sunds rays hit the equator perpendicular so it is C old at the poles bc the suns energy spreads out and hits at an angle. 

Why Transfer of heat drives severe storms? 

(5 reasons) 

·      Convection cell at the top of the atmosphere.  

·      2 convection cells

·      The 2 convection cells get broken up into 6 cells. (0-30 / 30-60 / 60-90à and back down)

·      Convection cells set up trade winds. 

·      Intersection of these cells is where there is tornadoes and disasters & jet streams.   

the earth is spinning 

** since it is a sphere as you go up in the poles the circumference gets less so the speed at which is is spinning is much slower.  

• the dividing line between polar cells (cold air) and ferrell cell (tropical air) 
• blows east to west 
• dips bring polar air (colder air) 

Rising air expands without change in heat content.  (temperature change without loss of heat):

1. Air mass expands available heat over large volume so the air becomes cooler.  
2. cold air loses temperature w/o losing heat so warm air expands and rises -- contracts and warms.
3. mixing hot wet air with cold dry air is not good

colder air is always going to stay below warmer air. 

** it displaces the wam air ** 

cold air mass does the moving

** it comes into a region and causes thunderstorms **

• rapidly lifts warm air to high altitudes, causing instability, condensation and precipitation 

warm air enters a region that has cold air 

** the warm air slowly moves up in a wedge shape turning in some rain (more gentle) **

• Rises over a flatter wedge of cold air, causing widespread clouds and storms.  

combination of warm and cold fronts come in at same time. 

** end up with rain for days ** 

thunderstorm qualities 

(4 steps) 

1. Warm, moist air absorbs enough heat to be MUCH less dense than surrounding air. 
2. Wam air rises HIGH, condenses into towering couds, releases heat, rises higher.
3.  Ice crystals form, become too heavy, ppt begins
4. Updrafts and downdrafts.  

• updraft side (not raining) 
• downdraft side (torrential downpour- where it releases heat) 

heat is gone and you just have a light rain 

** don't stop rising till water has turned from a liquid to a vapor ** 

• charge differences in clouds
• due to super-cooled droplets of water shattering and charges separating 
• Latent heat released, atmosphere explosively warmed, THUNDER. 
• ** Lightening and thunder are the same thing ** 

Hail 

(when and where?) 

gets about 100 days of storms per year.  

(also where you get the mighty tornados) 

the most dangerous thunderstorm 

& how 

storm that ends up spinning 

How: the jet stream whips by and sets the whole thing spinning.  

• most violent storm 
• winds up to 310 mph 
• move at 62 mph 
• funnel clouds form from atmosphere, many never touch ground. 
• core of whirling vortex less than 1 km wide, HUGE suction 

• form from normal thunderstorms
• air is drafted upwards 

Fujita Scale 

& how are they categorized

how tornadoes are measured 

(1-5) 

(categorized on wind speed and path length - how long it was touched down) 

thunderstorms over a wide area that gets spinning by the Coriollis Effect.  

(hurricane only in Atlantic) 

• has more energy than all the power plants put together in our world.  
• massive amounts of evaportaion in a wide area (rising air- low barometric pressure so winds rush in quickly) 
• eye = sunny clear = air is sinking 
• warm water in ocean > 80 degrees 

• warm moist air rapidly rises 
• circular winds from ocean rush in and rise. 
• Air expands, cools, precipitation forms, releases heat, rises even more
• rising air causes chimney - causes winds to descend in high pressure region

 low pressure zone (air mass rising over a large area) where winds converge that have a sustained speed of less than 39 mph

(Warns that it could be a hurricane.) 

low pressure zone (air mass rising over a large area) where winds converge that have a sustained speed between 40 -74 mph

  low pressure zone (air mass rising over a large area) where winds converge that have a sustained speed of > 74 mph (categories 1-5) 

San Francisco earthquake 

(movie) 

lasted 15 seconds and 62 people lost their lives. 

1985 Mexico City Quake 

turned land on builidings into soft and liquid material 

(earthquakes don't kill people buildings do) 

• Tornadoes strike with the intensity of a quake 
• More twisters develop in the Midwest in the US than anywhere else. 
• Violent winds up to 300 miles per hour.  

·      East Pakistan leaving 3000 dead. 

·      Hurricane Andrew (62 people dead in south Florida.)

·      Forms when warm moist air rises and cools.

·      The eye (hurricane center) à packed with intense thunderstorms.  

Movie: flood 

(2 places) 

·      Disaster in slow motion.

·      Struck Mississippi Valley in 1993 ( The tributaries were overwhelmed with rain and St. Genevieve almost was wiped off the map-- They made a make shift wall of sand bags.)

·      Southern France: rivers raised 50 feet in just a few hours. 

·      People often settled on flood planes

·      China in 1930s breached levies.  

the space shuttle / weather satellites. 

River qualities 

(3) 

1. carries nutrients 
2. body of water in motion
3. river drainage basins and divides 

River types 

(3) 

1. straight river 
2. braided stream 
3. meandering river 

o   typically in headwater

o   the velocity is tremendous 

** rare types 

o   Interfingering channels of water

o   Characterized by not having a lot of vegetation around them.(dry climates)

o   Carry huge amounts of sediments. 

** much less common 

o   Winds back and forth

o   Has a pattern

** most common 

** typical of wet climates 

scientists investigating how the width, depth, velocity and dischage are related

§  Greater Width = greater discharge

§  Greater depth = greater discharge

§  Greater velocity = greater discharge

§  Greater velocity = greater particle size that can be carried.  

Can be carried and is dictated by speed of water. 

** the discharge of a stream is the average water velocity multipied by the cross-sectional are of he stream.  

Q= a x v 

Q= (discharge) the volume of water a river can carry per unit time (EX: ft^3 / sec) 

V= (velocity)   the speed at which the river flowing (ft/sec)

A = cross- sectional river area (ft^2) (width x depth)

discharge vs. time

 (stick yard stick in a river and watch it rise and fall) 

** (change with the degree of infiltration - boston vs. forrested area) ** 

what is infiltration controlled by? 

(5 things) 

1. degree of urbanization 
2. antecedent soil moisture 
3. temperature - (hot = evaportate) (cold = ice so behaves like pavement so more flooding) 
4. type of soil 
5. slope 

problems associated with flooding 

(6 things) 

1. fatigue 
2. depression 
3. injury 
4. disease 
5. pests 
6. pollution

why do people settle on flood planes? 

(9 reasons) 

1. transportation 
2. food 
3. fertile soil 
4. water to drink 
5. waste flushing 
6. energy 
7. recreation 
8. river valleys flat and easy to build on 
9. aesthics

methods of flood control

(5 types) 

1. impoundment reservoirs / retention Basins (big concrete swimming pool that has a flu scape from the river) 
2. channelization (LA paves their river so there is no friction and water goes faster so there is no constraining on the banks) 
3. Levees: natural build up of sediment at a bank 
4. Flood Walls: New Orleans 
5. Dams: structure that impounds water

Why do we use dams? 

(3 reasons) 

1. recreation 
2. floood control energy 
3. drinking water supply 

why are dams bad? 

(2 reasons) 

1. they can fail 
2. massive loss of life associated with dams 

"Plan B" for floods

(5 things) 

1. Floodplain zoning regulations 
2. public education (town meetings) 
3. early warning and emergency response mechanisms 
4. compensation for flooding 
5. relocate towns that are flood repeatedly. 

adiabatic cooling 

1. fresh water is derived from evaporation of ocean water, some of which falls as rain or snow
2. Rain soaks in to become groundwater 
3. then seeps back into surface lakes and then ultimately back to the sea 

• air going up : expands and cools 
• air going down : compresses and warms 

Cut bank

where velocity is the fastest (outside of the curve) (erosion)

o   

Point bar

where velocity is the slowest (build up) - on the inside corner of the bend.  

the average time between floods of a given size.  

** longer flood discharges on a given stream hae longer recurrence intervals between floods. **