Natural Disasters Midterm 3

How is stream gradient calculated?

(elevation change)/(distance measured along channel)

What drove rapid land loss in Pacifica, California in the winter of 1997-1998? What were some of the different technologies and strategies that were implemented to try to slow/stop coastal erosion in these communities?

-2 feet of cliff retreat per year since 1950. -Tried to build seawall in Jan 1998 but winter storms stranded machinery. -Retreated > 30 ft in 2 weeks, Feb 1998.

What trends do we see in sea level over the past several decades? What drives sea level rise (two mechanisms)?

-90 mm from 1993-2016 -Heating of water and melting glaciers

What was the most deadly hurricane on record, and why was it so deadly? This has to do with where it hit.

-Cyclone Bhola Nov 12th, 1970 in Bangladesh. -Category 3 storm with 9 m storm surge (30 ft) overran low-lying densely populated islands at head of Bay of Bengal, killing 300,000 to 500,000

When do hurricanes form?

-Favorable conditions usually prevail in summer and early fall for tropical oceans; hurricane "season" in N Atlantic runs from June 1 to November 30 -Can happen anytime though

Where does sand go, when it leaves the beach? How does it reach the bottom of the ocean floor?

-Finer sediment out on shelf -Barrier islands, shorelines, and sand dunes

Why was Hurricane Mitch so deadly in Nicaragua and Honduras?

-Flooding and landslides -Left many people homeless and killed 70% of their crops

What conditions do we need in the atmosphere during the early stages of hurricane formation for them to develop?

-Further intensification -Intense surface pressure: gradient -Pronounced, organized rotation around central core -Winds >74 mph

Why do downbursts occur (what is the process that makes our "cold air balloons")? What kinds of wind speeds occur in downbursts?

-Hail or raindrops falling through drier air. Hailstones melt and raindrops evaporate. Endothermic process - absorbs latent heat from air. Cooler air more dense than the warmer air below. It falls as a "cold air balloon" to the ground. -Can reach wind speeds of 150 mph

Braided streams

-High sediment load -High velocity -Many channels -May have large variations in flow volume, easily eroded banks

How will climate change likely modify hurricane frequency and intensity?

-Hurricane strength correlates with sea surface temp. (SST) as most energy derived from heat stored in ocean water -Global Warming will increase SST and augment the number and intensity of hurricanes

How do most hurricanes start (what generates the initial disturbances that build into these storms)? Where do they start?

-Hurricanes start as clusters of thunderstorms (disturbances) -Disturbances in N. Atlantic form in 3 ways (all involve convergence of surface winds): -Inter Tropical convergence Zone (ITCZ) -Convergence of air at the end of a mid-latitude frontal boundary in the Gulf of Mexico or east coast of Florida -Easterly waves, tropical disturbances from N. Africa near ITCZ. Converging winds on east side of wave are associated with thunderstorm development. 60% of all storms, and most big Atlantic hurricanes

In Iowa, when do we tend to get thunderstorms and how many thunderstorm days a year do we have? Where else do we get a lot of thunderstorms in the US (two main regions),and why? The mechanisms are different.

-Iowa has about 50 days of t-storms per year -Gulf of Mexico area (FL, GA, AL, MS) due to warm and moist air -Front range of rocky mountains because of warm and cold air masses colliding

What is a recurrence interval, and how do we calculate it?

-It is how often can we expect a given sized flood to occur R(recurrence Interval)=(N(number of floods within the time span) +1)/m(rank of flood) shorter version: R=(N+1)/m

How does turbulent flow differ from laminar flow?

-Laminar flow: an idealized channel Water moves in parallel lines (maintain velocities) -Turbulent flow: water does Not move in parallel lines Changes in velocity in individual streams

Meandering streams

-Low sediment load -Low velocity -One main channel -Common in streams flowing on low slopes in plains or lowlands, cutting through fine sand/silt/mud

How much did Miami Beach spend in the 1970s and 1980s on their beach nourishment program? What are the issues with beach nourishment-how and why do costs change over time, and how does it impact the environment? How much maintenance do beaches need?

-Natural beach nearly gone by 1950's 1970's___ nourishment program ___Artificial____ placement of sand on beach Protects coastal property from wave damage Cost $62 million over 10 years - Minimum of _____$1 million____/mile Expanded in 1980's to build dunes Requires continual maintenance

Seasonal Changes in beaches

Summer in CA: gentle waves add beach sand. Winter in CA: storm waves cause erosion.

What ingredients do we need for a hurricane to form? Because of these ingredients, where and when do hurricanes form?

-Need __warm__ sea surface temperatures (27°C/80°F or greater), plus high humidity, & low wind shear. -Favorable conditions usually prevail in summer and early fall for tropical oceans; hurricane "season" in N Atlantic runs from June 1 to November 30

Why don't hurricanes form at the equator?

-Needs Coriolis effect to deflect winds blowing towards low pressure to produce rotation -Coriolis effect is too weak near the equator to start rotation

How do we name hurricanes (what does the list for each year look like, how many lists are there, and why do we pull names occasionally from lists)?

-Short names used since 1953. -Only women's names until 1979, men's names now alternate. 6 lists of 21 names used in rotation (no Q, U, X, Y, Z names). Only time there is change in list is if storm is deadly or costly, so future use would be inappropriate for reasons of sensitivity: e.g. Katrina, Camile, Andrew, Ike, Wilma, Sandy (must be requested by affected country) In the event that more than _21_ named tropical cyclones occur in the Atlantic basin in a season, additional storms take names from the Greek alphabet: Alpha, Beta, Gamma, Delta, and so on.

How do we define cyclonic storms (what do they look like)? How does a tropical cyclone expand on this definition?

-Storm defined by low central atmospheric pressure and inwardly rotating winds -A warm-core, non-frontal cyclone, originating over tropical or suptropical waters, with organized deep convection and a closed surface wind circulation about a well-defined center -Symmetrical -Once formed, a tropical cyclone is maintained by the extraction of heat energy from the ocean at high temp. and heat export at low temperatures of upper troposphere

When and why do hurricanes die? You should know and be able to explain several mechanisms.

-Storm moves over cooler water that can't supply warm, humid tropical air, or remains stationary. -Storm moves over land, cutting off source of warm air. Note - reduces wind speeds but moist air can still dump large quantities of rain in inland areas. -Storm moves into area where large-scale flow aloft is not favorable for continued development or sustainment (i.e. wind shear, low-P).

How do temperature and pressure change as we move upwards through the troposphere?

-Temperature gets cooler as you move away from the ground -Less air pressure as altitude increases

From page 2, bottom right, what do streams do?

-They transport sediment (erosion) -They move water, either in laminar or turbulent flows -They weather the material (bedrock or sediment) that they flow over

How do wave height, velocity, and wavelength change as waves approach shore?

-Wave height increases -Wave length decreases -Velocity decreases (period doesn't change) -Energy dissipated as wave breaks -Causes movement of water, sand, and rock

What is wave refraction, and why does it occur?

-When the wave in shallow water is slowed down, causing it to bend and approach nearly parallel to shore. -Occurs to erode headlands and smooth out the coastline

What do cold fronts look like? (steepness, which air mass is pushing into which other airmass, relative temperatures of air masses, precipitation patterns, clouds)

-cold air advancing into warm air -steep frontal zone -cold, dense air sinks, forces warm air upwards -heavy showers, cumulonimbus clouds

What about occluded fronts? (which air mass is pushing into which other air mass, relative temperatures of air masses, precipitation patterns, clouds) Additionally, how do occluded fronts basically shut themselves off, in terms of long-term storm producing potential?

-cold front advances more quickly than warm front -cold air more dense, homogenous temperature -cold front overtakes warm front, warm air mass forced off ground -may briefly intensify precipitation, but ultimately cuts off energy source and moisture, storm dissipates -low may redevelop

Ice-jam floods

-melting ice-floes dam a portion of a river -normally in spring, causing it to flood upstream. -Occur in regions where rivers freeze and then begin to receive surface water from rainfall of nearby melting.

What do warm fronts look like? (steepness, which air mass is pushing into which other air mass, relative temperatures of air masses, precipitation patterns, clouds)

-warm air advancing into cold/cool air -shallow frontal zone -leading edge of warm air unable to displace cold, dense air at surface -wedge shape: warm air slides gradually over cooler air -T-version, low stratus clouds, typically: light to moderate rain -can produce thunderstorms ahead of front especially in summer

What proportion of coastal homes (within 500 feet) do we anticipate could be lost to erosion in the next 60 years?

1-4 homes within 500 ft. of US coast could be lost to erosion in next 60 years.

What are the three different kinds of severe thunderstorms? You should know what these look like and how they work.

1. Mesoscale convective complexes (MCCs) 2. Squall Lines 3. Supercells

What are our three ingredients for thunderstorm formation? Why are these three different factors necessary?

1. Water vapor in lower atmosphere to feed clouds and precipitation 2. Unstable temperature gradient so air rises rapidly 3. Trigger - something starts humid air rising

What three factors determine wave height?

1. Wind duration 2.Wind velocity 3. fetch (distance over which wind blows)

Know, in order, the four layers of the atmosphere.

1.Troposphere 2.Tropopause 3.Stratosphere 4.Stratopause 5.Mesosphere

When does a wave break?

1/20th wavelength -> waves break

How much water to float vehicles?

12"

How many thunderstorms are occurring on Earth (average) at any given time?

1800 at any given time worldwide

What percentage of Earth's water is freshwater?

2-3%

How long do supercell thunderstorms last?

2-4 Hours

How high can winds be in a tropical cyclone?

215 mph

How fast is a tropical depression?

23-30 mph

How much water needed to carry away most vehicles?

24"

How many coastal states are there in the United States, and what is the average rate of coastal erosion?

30 coastal states in US: Average US rate of coastal erosion is 2-3 ft/yr.

How fast is a tropical storm?

40-73 mph

You should know the probability of a flood of a given recurrence interval occurring any specific year. If we ask a question like this on the exam, we will keep the math simple enough that you should be able to do it without a calculator.

50 year flood: 2% 100: 1% 500: 0.2%

How much water does it take to stall a passenger car?

6"

What percentage of the world's rivers are dammed?

60% of world's rivers are dammed.

What was the tallest ocean wave height measured during Hurricane Ivan?

90 ft

What are the different hazards associated with hurricanes? You should know how these work (ex. Storm surge, rogue waves, tornadoes, etc.). For example, how does storm surge relate to pressure differences and winds?

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What is an isobar? Why do isobars get more tightly packed together as storm systems strengthen? Relatedly, why do systems get more circular as they strengthen, and why does the eye get smaller?

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Why does wind shear matter to hurricanes (if we have high wind shear, what will happen to a developing hurricane)?

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Oxbow lake

A bow shaped lake formed in a former channel of a river

Meander scar

A dried out oxbow lake

What is a barrier island, and what features do they have? Are they permanent features? How do they form?

A near-shore, coast-parallel island of sand built up by waves and currents and capped by wind-blown sand dunes. Grow parallel to the coast by longshore drift

What are air mass thunderstorms?

A thunderstorm not associated with a lifting mechanism, but rather with warm, moist, and unstable air-masses

How do rivers weather and erode material (3 processes?)

Abrasion: water-borne particles physically break off pieces of other particles they come into contact with Turbulent flow: loosens and lifts material form stream bed using water pressure. Dissolution: chemical weathering of soluble material (will dissolve in water).

Know the different super outbreaks from lecture and their characteristics (how many tornadoes, etc.).

April 3-4 1974 "Super Outbreak" 2nd most extensive outbreak: _148__ tornadoes in 18 hours. 315 people died. As many as _15_ tornadoes on ground at any single time 95% of tornadoes were "significant" (>111 mph winds), 30 x F4&F5 (>166 mph) No other outbreak has produced _6 F5 !!! April 2011 "Super Outbreak" Most extensive outbreak: _358__, April 25-28, _199__ in 24 hour period April 27 316 people died on April 27, mostly in Alabama.

What is needed for hail to form (how does hail form)? What has to change within a storm to go from making small hail to making larger hail?

As thunderstorms move air vertically in the updrafts, moisture is being pushed to higher altitudes, where it freezes Hail takes on a spherical shape as the moisture droplets become larger as more water is frozen to its surface due to being repeatedly moved to higher altitudes

At what depth does a water wave start feeling the bottom?

At depths of half of a wave's wavelength or less, waves start to "feel" bottom

How many named storms form in the Atlantic every year on average, and how many strike land? What was the worst year and how many Category 5 hurricanes did we have?

Average - 21 Worst year - 2005 (28) Most category 5 storms - 2005 (4)

How do dams modify base level?

Base level: the level to which a stream can erode Ultimate base level; sea level Dams Starve the stream below the dam , and accumulate sediment above the dam, this is why dams don't last forever (they fill in).

Why is Fire Island, New York so vulnerable to coastal erosion? What would happen if a hurricane came through this area? What were the effects of Hurricane Sandy's storm surge?

Because strong storms bring more energy to the coastline causing higher rates of erosion Hurricane would be very strong and deadly Sandy Surge was focused in bays and harbors (__13.9__ ft at one shoreline in NYC)

How do rivers transport sediment (3 processes?)

Bed Load: sediment is bounced and rolled across the stream bed (large clasts) Suspended load: sediment is suspended by the water (medium/small clast). Dissolved load: stuff that is dissolved in water (sodium, calcium, etc).

Johnstown, PA dam failure flood-you should know about the magnitude of this disaster, and the conditions that allowed it to occur (both weather and dam maintenance, as well as the location of Johnstown)

Began at south fork fishing and hunting club (where dam was at) Hit a boiler that exploded that created a black death mist barbed wire in the water Killed 99 entire families, including 396 children 98 children lost both parents 1 of every 3 victims never identified (777)

Blue Jets (lightning)

Blue jets are cones of blue light brighter than sprites that spray upward from the tops of thunderclouds up to an altitude of about 25 miles at speeds of about 22,370 mph.

Relatedly, what has happened recently at Oroville Dam in California?

California had been experiencing lots of rain that eroded the dam. When they opened up the dam to let water out there was a hole in the runway.

How are rogue waves generated?

Caused by constructive wave interference that usually occurs unexpectedly amid waves of smaller size

What does wave action do to irregular shorelines through time?

Causes headlands to erode faster than bays due to stronger wave energy

Which way does a hurricane rotate in the Southern Hemisphere?

Clockwise

What is the rate of land loss in Louisiana, and why is Louisiana losing coastline so rapidly?

Coastal Louisiana has lost an average of 34 square miles of land...per year for the last 50 years. From 1932 to 2000, Louisiana lost 1,900 square miles of land, roughly the size of the state of Delaware

Which is denser, cold dry air or warm moist air? Why?

Cold dry air because it has higher pressure

Which produces larger waves constructive or destructive?

Constructive produces larger waves

Which way does a hurricane rotate in the Northern Hemisphere?

Counterclockwise

You should be able to label a "wave anatomy" diagram, and should also know the different definitions given in class for these terms.

Crest: highest point Trough: lowest point wavelength: distance between two crests, or two troughs Wave height: vertical distance between crest and trough Wave period: time it takes for two successive crest or troughs to pass a point

What are thunderstorm clouds called? What modifier do we add on to the end of a cumulus cloud name to indicate that it is producing rain?

Cumulonimbus Clouds (thunderstorm clouds)

How tall can thunderstorms get (what area of the atmosphere can they reach)?

Cumulonimbus clouds can rise over 21 km (65,000 ft) well into stratosphere

Regional name for cyclonic storm in Indian Ocean and South Pacific

Cyclone

What is the most intense storm in terms of wind speed ever recorded in the southern hemisphere, and when did it come ashore?

Cyclone Winston- This time last year

Which country experiences the most tornado fatalities, and why?

Europe - Poor construction and not a lot of warnings

Know hurricane anatomy and where winds are the strongest and weakest. What would it be like to be in the eye of a hurricane vs. standing in the eye wall (which would be a better place to stand)?

Eye: Calm air and relatively clear conditions characterized by a column of descending cool, dry air Eye Wall: Thick mass of moisture-laden clouds spinning at a high velocity. Most dangerous part of a hurricane

What kind of flood causes the most fatalities, and what causes 50% of the fatalities WITHIN these sorts of events?

Flash floods becuase... Vehicles- trapped or drown

What is the mesocyclone?

Forms when horizontal rotating winds are lifted into upright vortex few to 10+ km in diameter. Provides very strong updraft in supercell and is responsible for maintaining intensity of storm and rotational vortex for tornado.

How do we rate tornadoes? Know the scale names.

Fujita Scale Enhanced Fujita Scale

What was so special about the very recent Hurricane Patricia?

Highest winds only affected small area (~15 miles across) Came ashore in very mountainous region Dissipated quickly Remnant Low -heavy rainfall across Texas, Louisiana

Regional name for cyclonic storm in the North Atlantic and East Pacific

Hurricane

Why does lightning occur (what do we need)?

Lightning: intense electrical discharge between (-) and (+) charges in cloud, between clouds, or cloud to ground.

Why do hurricanes rotate, and which way do they rotate in the different hemispheres?

Hurricanes rotate because of Coriolis Effect -Northern Hemisphere - Counterclockwise -Southern Hemisphere - Clockwise

What to do during a tornado

In sturdy building: lowest interior room (prefer. basement). Crouch, cover yourself with mattress, helmet etc. to protect from flying debris. (don't worry about opening windows) In tall office building: interior stairwell or room In mobile home: try to get to a storm shelter. NOAA even recommends trying to find shelter in open rather than staying in mobile home. In automobile: Drive at right angles to path of tornado (if path is clear and it is possible). Otherwise, seek shelter (not under bridge!) In open: get away from trees, cars, etc., lie down (preferably in low ground), protect head

How are the updrafts and downdrafts of a supercell storm related, spatially (where are they within the storm)?

In the middle of the thunderstorm

How might climate change modify the amount of flood damage expected over time?

Increase the amount of flood damage over time! -For every 1०F increase in temp, the atm can hold 4% more water -Floods in 1960: 394, 1990: 2,444

Relatedly, what does a Hjulstrom diagram illustrate?

It illustrates the particle size and flow velocity of particles eroded, particles transported, and particles deposited.

Does the Coralville Dam and Reservoir stop large floods from occurring?

It is decreased but still occurs

When did the most expensive outbreak of tornadoes occur, and where?

Joplin, Missouri; May 22, 2011

How do we define rogue waves, in terms of their size?

Large solitary wave that occurs unexpectedly amid waves of smaller size

How does latent heat released during condensation help thunderstorms build?

Latent heat energy increases instability

How energetic is a lightning bolt, and how hot is it? How about a superbolt?

Lightning Bolt: -Typically __5,000___- __20,000____ amps In <1 sec air heated to 8,000 to 33,000º C (_3x_ hotter than surface of sun!). Superbolt: -Rare (__.2% of all lightning bolts___) more than 100 times more powerful in brightness and energy than ordinary lightning (108 - 109 volts; 1011 - 1014 W; 75,000 - 300,000 amps).

Know our different lift mechanisms that can get air masses rising.

Low-P and convergence Surface heating Orographic: topography causing air to rise Frontal: warm fronts or cold fronts causes air to start rising

How do meandering and braided streams differ from each other? You should be able to talk about differences in sediment load, velocity, and number of channels.

Meandering streams: -Low sediment load -Low velocity -One main channel -Common in streams flowing on low slopes in plains or lowlands, cutting through fine sand/silt/mud Braided streams: -High sediment load -High velocity -Many channels -May have large variations in flow volume, easily eroded banks

What is the most damaging type of severe storm? Which type of severe storm most commonly forms tornadoes and has large hail?

Most damaging & most commonly forms tornadoes - Supercells

Which direction do most tornadoes rotate?

Most rotate counter-clockwise.

If the heaviest rain and hail has passed in a storm, are you safe from tornadoes?

NO. Often pass AFTER heaviest rain and hail have passed.

Are barrier islands a good place to build homes? Why or why not?

No ****ing obviously it's literally sand. Barrier islands are very susceptible to extensive damage: they're just sand dunes held together by vegetation

Why DON'T hurricanes form in the South Pacific, the South Atlantic, and off the coast of California?

Ocean water isn't warm enough for the coriolis effect to occur

Why do we see a lot of hurricanes forming in association with ITCZ, and what is the ITCZ?

One trigger for convergence is the meeting of the Northern and Southern Hemisphere easterly trade winds near the equator. The meeting of these wind belts triggers numerous, daily thunderstorms in a region called the Intertropical Convergence Zone (ITCZ).

What is wrong with our current definitions of flood plains in Iowa City?

Our current calculations rely on only flood events that have occurred after the Coralville Reservoir and dam were constructed. What this means is that we miss several very high flow events that happened before this construction. We think that high flow events will likely go over the dam, which means that our floodplains as currently defined are too optimistic (what we think is a 100 year floodplain- i.e., something that on average should only flood every 100 years-instead is more likely to flood on average every 20 years). So we are building in places that we probably should not be, as a result.

Nourishments

Placing sand on an eroding beach

How can you avoid getting hit by lightning? You should know best practices.

Plan ahead Avoid open, high-ground, isolated trees etc. Scatter groups Stay away from conductors (e.g. water)

What is a hydrograph? How does modifying land use (specifically, making it more urban by paving and making more hard surfaces) change the shape of a hydrograph, and why?

Plots of: stream flow vs. time There is a high steep stream discharge compared to time in urban areas. And more gradual in rural areas

Where does the heaviest precipitation, lightning and rain occur in a supercell thunderstorm?

Rain/Hail Cloud: Heaviest precipitation, most violent rain, hail, and lightning on outer edge of updraft.

What are the other hazards associated with a tropical cyclone besides wind speeds?

Rainfall, storm surge, possibly tornadoes

What is the Saffir-Simpson Hurricane Scale based on?

Ranks (1-5) damage potential of land-falling hurricane according to sustained wind speed

Elves (lightning)

Reddish, ultra-fast bursts of electricity bright enough to see during the daytime high in the Earth's atmosphere. But elves are ring-shaped halos that can spread to more than 185 miles wide.

Natural levee

Result from deposition, accumulation of sediment along banks during flood events

Revetments

Riprap or interconnecting concrete blocks used to protect dunes and beaches from erosion

Jetties or Groins

Rock walls or piles built perpendicular to the beach. Generally used to block flow of sand and prevent ship channels from filling in

Can we predict sediment movement (where erosion and deposition will occur)? What about longshore drift? Given a diagram, you should be able to indicate where sediment will be eroded from and where it will be deposited.

SEDIMENT MOVEMENT IS PREDICTABLE! Longshore drift- moves sediment along the coast

What is the scale that we use to define hurricane intensities? Which side of a hurricane is most destructive, and why?

Saffir-Simpson Scale: Ranks (1-5) damage potential of land-falling hurricane according to sustained wind speed -Most destructive side (wind and storm surge) is parallel to storm forward motion.

What is a turbidity current?

Sediment piles up at head of submarine canyon, then slides, forming a "turbidity current" Turbidity Current - moving downslope under influence of gravity

How do you construct a good seawall (what should its characteristics be)? How has the Galveston seawall affected the shoreline and the beach in front of it?

Should be built parallel to the coastline to protect structures on the beach

Where in the United States is coastal erosion highest?

Southeast and Gulf Coast

What are spring vs. neap tides? Why do spring and neap tides occur?

Spring tides - Largest variation between high and low tides Neap tides - Lowest variation between high and low tides They occur because of the sun's gravitational pull on the oceans

When (seasonally and time of day) do we tend to get tornadoes, and why?

Spring, 2-8 PM

You're caught in a rip current! How do you get out of it?

Swim parallel to the shoreline to get out of the current, which is usually between 15 and 45 meters wide

What controls the Earth's tides?

The relative position of the Sun and Moon to the earth controls the earth's tides

Given a diagram or description of a meandering stream, you should know where erosion is happening and where deposition is happening.

The water on the outer edge moves much faster than the water on the inner curve, this results in erosion along the outer bank (cut bank), and deposition along the inner bank (point bar)

Sprites (lightning)

They are reddish bursts of electricity at altitudes of about 50 miles (80 kilometers) that last less than a second but are bright enough to see in daylight.

What does it mean for a feature to be ephemeral?

To last a short amount of time

When did the deadliest outbreak of tornadoes occur, and where?

Tri-State Tornado: March 18th, 1925

Regional name for cyclonic storm in West Pacific

Typhoon

Why do we get so many tornadoes in this country? What percentage of global tornadoes do we get?

US gets about 75% of all tornadoes: climate conditions in plains are perfect.

Globally, where do we see the most thunderstorms and why?

United States with over 100,000 a year

Dam failure floods

Usually a result of faulty engineering (NOT natural disasters)

Seawalls

Walls built on land and parallel to the beach to absorb and reflect wave energy.

Turbulent Flow

Water does NOT move in parallel lines Changes in velocity in individual streams Like when you turn the sink on really hard

Laminar Flow

Water moves in paralell lines Individual paths maintain their velocities Like when you GENTLY turn a faucet on

How are wave energy and wave amplitude (height) related?

Wave energy is proportional to wave amplitude squared

What factors contributed to make the 1993 Mississippi River floods so devastating? This is related to weather-we had an unusual several months preceding this event.

Wet fell 1992 and heavy snowfall in winter- saturated soil in the upper Mississippi-Missouri catchment area Entire region had above average rain beginning in April From June through early August, East Central Iowa got ~38.5" rain 50 fatalities $15 billion in damages 50,000 homes destroyed or damaged 75 towns submerged May-September: North Dakota, South Dakota, Nebraska, Iowa, Missouri, Wisconsin, Illinois 100 year flood for Iowa City

Why do isobars get more tightly packed together as storm systems strengthen? Relatedly, why do systems get more circular as they strengthen, and why does the eye get smaller?

When isobars are very close together, the atmospheric pressure is changing very quickly in that location. This rapid pressure change causes the air to move quickly from the area of higher pressure to the area of lower pressure. Fast moving air = strong winds.

Can we have two 500-year floods in a 3-week period?

Yes

Can hurricanes form in January?

Yes, Hurricane Alex; Jan 13-15, 2016

How do we define the term "stream"?

any flowing body of water, large or small

Windward side of a mountain range (precipitation?)

consistent rainfall

How does eye diameter affect hurricane wind speeds?

eye diameter= change in intensity: smaller eye= higher wind velocity (law of conservation of angular momentum).

Flood plain

flat, low-lying area along channel subject to floods. Fine grained sediment.

Flash floods

intense local rainfall causes stream to suddenly flood small area, usually local watershed

What is an isobar?

line of equal pressure plotted on weather map

Rivers

major branches of a large stream system

stream stage

measures stream height. Once water height is high enough to jeopardize human structures/safety, flood stage is reached

Constructive interference

obtained by interference of in-phase waves

Destructive interference

obtained by out of-phase waves

How do rainbands compare to the eyewall in terms of both strength and hazards?

rain bands: bands of heavy convection (thunderstorms) spiraling around and towards storm's center. Wrap around eye wall. Can produce heavy bursts of rain, 1/2 to 2/3 the strength of eye wall. Also can have tornadoes.

Leeward side of a mountain range (precipitation?)

rain shadow from sinking air downward

stream discharge

represents how much water is actually passing a point at any given time (cfs-cubic feet/second)

Regional floods

river overflows banks on a large scale, flooding entire regions

Where does beach sediment come from, and how do beaches change both from day to day and seasonally?

rivers, cliff erosion, coastal transport processes. Topography changes day to day. Dams on rivers prevent replenishment of beaches.

What IS thunder (what are you hearing)?

sound produced by intense instantaneous heating and rapid expansion of air around lightning channel = supersonic shock wave.

What is a drainage basin, and what features on the Earth's surface form drainage divides?

the area drained by a river and all its tributaries

What is significant wave height?

the average height of the highest 1/3 of the waves.

Why do we need warm ocean surface water for hurricanes to form, and how deep does this water need to be?

warm ocean water (27°C / 80°F) to depth of ~50 m / ~160 ft: supplies heat and instability to overlying atmosphere needed to sustain storms

When a new largest flood beats the previous record largest flood, what happens to the recurrence interval of the now second largest flood?

~1/2