Natural Disasters

Final Exam Review

Storm stages

• tropical wave

• tropical depression or disturbance

• tropical storm (gets named from here)

• hurricane (74 mph winds)

What is fire?

rapid combustion

• combination of O2 with carbon, hydrogen, and other elements in a chemical reaction that produces light, heat, and flame

• exothermic reaction (releases heat) o can think of it as the opposite of photosynthesis

Fire stages: pre-heating

water is expelled from wood/fuel

this is accomplished through:

• flames (nearby fires)

• long periods of dryness (lack of rain, drought)

Fire stages: pyrolysis

thermal degradation of wood cellulose (stable to about 615 F)

• gives off flammable gasses and water vapor

• ash

• gas movement causing cracks in the wood

• can BECOME flames

Fire stages: flaming combustion

pyrolyzed wood burns hot and fast

• greatest energy released

• highly efficient; predominates in windy environments

heat transfer through:

• radiation

• convection

• conduction

Fire stages: glowing combustion

after the active flames die off; coals

• wood slowly consumed in oxidation reaction

• lower temperature!

Fire burn direction

Up!

• up slope

• heat rises

2005 hurricane season

Worst season on record until 2020

• 27 names storms

• 7 considered major

Hurricane seasonal average

10 named storms, 6 hurricanes, 2 major

Pacific Ocean name for hurricane

Typhoon

Indian Ocean name for hurricane

Cyclone

tropical wave

• initial low pressure disturbance

• unorganized

• moving west

• winds < 20 mph

tropical depression or disturbance

• moving mass of thunder storms

• starting to organize

• assigned a number

• winds < 39 mph

tropical storm

• gets named

  • alternating male/female names starting with "A"

• distinct rotary/cyclonic motion

• winds 39 – 74 mph

Hurricane

• well-defined circular structure with large rain bands

• central "eye" of low pressure first forms

• winds > 74 mph (increasing to > 150 mph)

Northern Hemisphere hurricane turn which way??????

Counterclockwise

Cat 2 hurricane in terms of energy from hydrogen bombs???

Hundreds

Hurricane conditions in the beginning

calm wind patterns

• for several days and 100s of miles

warm ocean surface (80 degrees)

• as well as 200 feet below

vertical disturbance in the atmosphere

Saffir Simpson scale

measured in categories (1 through 5)

• function of wind speed and storm surge

  • potential damage

  • potential damage is not linear with category

Saffir Simpson scale: cat 1

wind: 74-95 mph

effects: No real damage to building structures

Saffir Simpson scale: cat 2

wind: 96-110 mph

effects: Minor damage to buildings. Considerable damage to vegetation

Saffir Simpson scale: cat 3

wind: 111-130 mph

effects: Some structural damage to small residences. Mobile homes are destroyed. Flooding near the coast.

Saffir Simpson scale: cat 4

wind: 131-155 mph

effects: Complete roof structure failure on small residences. Major erosion of beach. Major damage to lower floors of structures.

Saffir Simpson scale: cat 5

wind: >155 mph

effects: Complete roof failure and major damage to all structures located less than 15 feet ASL

Storm surge

large volume of rain/runoff prior to landfall of the hurricane

• 90% of all fatalities in a hurricane caused by storm surge

• large amounts of erosion

Storm surge from 3 factors:

• force of the waves (including debris in the water)

• hydraulic lift (upward force) under structures

• reflected wave energy from man-made structures

Factors in storm surge SEVERITY

• wind speed

• tide stage

• low pressure

two types of surge:

flood surge: water brought onto the land by the storm

ebb surge: water floods off the land to the sea

Where is wind moving fastest on that there hurricane moving north?

Doppler radar

Examines final movements prior to landfall

• hours to days timescale

visible and infrared satellite images

• Every 30 minutes on average

  • can be acquired pretty fast

Planes flying through hurricane storm center

• measure vertical structure, wind speeds, pressure, and temperatures

• use drop-sonde instruments to relay information regarding the change with height

Hurricane Andrew

Category 4-5

Bahamas —> Florida —> Louisiana

COSTLIEST IN U.S. History (UNTIL KATRINA)

COULD have been worse if it landed a bit more north

Hurricane Katrina

Costliest Atlantic hurricane in history!!!

• costliest damage at eye wall

• mini swirls did happen!

• Florida, to the gulf, to Louisiana after it regained energy

• Cat 5 in the Gulf

NOVA: Flood! (The Great flood of 1993)

Flooding in the Midwest! (Mississippi River)

• unusually wet Summer

  • JETSTREAM stayed over the Midwest month after month (storm highway)

• weakening levees

• all out war against nature

  • bringing in more dam/levee supplies

  • multiple levee breaks/multiple crests

St. Louis

• big ass floodwall broke!

• broken levee on the Columbia side relieve pressure on St. Louis and the propane tanks

• 9 state area

• costliest flood in U.S. hisotry

Mini swirls

small localized swirls within the eyewall

Flood

damaging floods result when the volume of river/stream flow exceeds natural barriers and/or the levels of flood preparedness

 because flow is greater or longer than expected

 because of an incomplete understanding of local hazards

Natural flood causes

• heavy rain

• dam failure

• rapid snowmelt / ice jams

• deforestation

• steep slopes

• storm surges during tropical storms / hurricanes

Deadliest flood disaster

Johnstown floods

Infiltration capacity

capacity of a soil to absorb water

High infiltration rates

• coarse soil

• well-vegetated land

• low soil moisture

• porous topsoil

poor infiltration rates

• impermeable crusts in the soil

• salt layers

• cold weather (frozen soil has poor infiltration)

• compaction

• paved (impervious) surfaces

Hydrograph

discharge rate (Q) in m3/s (plus rainfall amount) versus time

• measured by a stream gauge

• varies with infiltration capacity and rainfall amount

Case Study: Pittsburgh flood 1936

Flood Control Act 1936 and 1938

primary causes

• prolonged precipitation (snow & rain)

• high intensity, shorter duration rains

• certain areas had large flash floods

• steep slopes, thin soil cover, low vegetation

Power and water cut off; contamination by sewage

Flood Control Act 1936 and 1938

Flash flooding of Washington Blvd. in Pittsburgh

Aug. 19, 2011 at 4:30pm (rush hour) o 1.79 inches of rain in 30 min

• volume = 208 Olympic sized swimming pools

• 10 feet of water rapidly rose on the roadway

• sewer capacity was exceeded

• killed 4 people

Miramichi Fire

October 1825 (Maine & New Brunswick)

• a summer of sparse rain

• strong winds spread smaller camp and settler’s fires

• among the worst wildfires in North American history Page 2/6

• burned 3.9 million acres

• killed 160 - 500 people

• left 15,000 homeless

Bad trees for fires D:

Ponderosa Pines

• western U.S.

• cones don’t open until a certain temperature is reached

Eucalyptus

• high oil content

Riskiest area in the world for wildfires

the Mediterranean

Northern California: Mendocino complex fire

burned more than 459,000 acres

• the largest complex fire in the state's history

Diablo winds

Originate inland in areas of high pressure

• air becomes hotter and drier as it heads west towards the low pressure coast

• speed up as they are forced through narrow spaces (canyons and mountainsides)

• if they hit already dry area, they can fan the flames and carry the wildfire overland

Early earth

was more similar to present-day Venus than what we have today

• extreme volcanic activity

• high CO2 in atmosphere (we talking 98% yo) and hotter temperatures

Where that early earth CO2 go??

Its in the limestone and other organic material!!! (80% of it)

• resulting from plate tectonics and rock cycle

rest went to oceans and living material

Oxygen isotopes

we can examine changes in rock and fossil composition over time  for example: O2 isotope ratio in shells (think back to those early lectures!)  there are three isotopes of O2 (16O, 17O, 18O) - 16O is the most common Page 2/6  evaporation from the oceans favors lighter isotopes  therefore, precipitation concentrates 16O and 17O on land (in ice/snow) and 18O gets concentrated in the sea  if the amount of 18O/16O is measured in shells, scientists know about the conditions of the water at the time they were formed - lower 18O meant warmer conditions

Greenhouse gasses

allow solar energy in but trap the radiant heat from the Earth from escaping

• water vapor (H2O)

• carbon dioxide (CO2)

• methane (CH4)

• nitrous oxide (N2O)

• ozone (O3)

• CFC’s

Intergovernmental Panel on Climate Change (IPCC)

• 100’s of scientists meeting and reporting their findings on climate change

• assess current models/predictions

• report areas of uncertainty

High level findings from IPCC

warming of climate is not in question

• 90% of all warming since 1950 is due to human activity

• all greenhouse gases are at their highest amount in the past 650,000 years 

• the probability that this is all from natural causes is < 5% 

• average world temperatures could rise from 1 to 6° F by 2100 

• > 60% chance of increased droughts, hurricanes, and extreme tides 

• > 90% chance of more frequent heat waves and heavy rainfall 

• a rise in sea level of between 7 – 23 inches 

• levels now will continue to affect the climate for the next 1,000 years!

Climate mitigation options

changes in technology o carbon-free or carbon-neutral energy technologies for power plants, cars, etc.

• takes time (politics) o cap and trade 

limit CO2 emissions through a market-based trading system 

• CO2 producers pay more for emissions credits 

• non-CO2 producers gain by selling credits

air scrubbing

• possible but VERY expensive right now o

fertilizing the oceans with FeSO4 to grow algae (similar to massive tree planting)

• algae would take up CO2 

• effects on the ocean’s biosphere unknown?

weathering of rocks

• pulls CO2 out of atmosphere and makes carbonic acid 

• also, very slow

geoengineering 

• inject large amounts of particles into the atmosphere to reflect solar energy 

• similar to a volcanic eruption 

• risks unknown? 

carbon sequestration 

• capturing CO2 and injecting it deep underground in a liquid form

Taxonomy order

kingdom  phylum  class  order  family  genus  species