This is part #1 of 3 parts to the PowerPoint presented in class on Monday, August 5.

This is part #1 of 3 parts to the PowerPoint presented in class on

Monday, August 5.

Chapter 9 – severe weather

Chapter 10 – cyclones

Chapter 11 – coastal hazards

Chapter 12 – atmosphere

Chapter 13 – wildfires

Chapter 14 – Airbursts and impacts

Recent U.S. NewsSalt Lake valley has recorded 17 (now 19) days above 100 degrees F (record = 22)

44 U.S. tornado deaths (55 rough average)

Eight U.S. tropical storm deaths, but no genuine hurricanes so far in 2013.

History Channel said that California state capitol Sacramento has 185 miles of levees. Most were poorly by farmers, but are now serving to protect heavy urban development. (Oops).

Flood potential from the Sierra Nevada mountains is a severe threat, and Sacramento levees continual to fail periodically, with or without floods.

In Sacramento (and nationally) there is scant information on who owns or controls levees, how they

were built or how people would react if they failed.

A ‘levee’ canal in Taylorsville failed in 2013. The local news said that authorities were trying to find out who

owns the levee, even as sandbags were being filled.

A levee failed in Logan in about 2011, killing three people. The sun was shining that day.

Post-event authorities were trying to figure out who was responsible for the levee.

Let’s integrate across topics for a moment:

Recall a quake researcher on the History Channel:

She suggested that we stop trying to predict or forecast earthquakes.

Instead, she recommended that we just prepare for them so we really don’t require a warning system.

What does “mitigate” mean?(page 318)

Anything that reduces the effect of a natural event, otherwise known as “preparedness”.

My red-neck brother said,

“Forget the building inspector”.

(Turns out - - what my bro’ meant was over-build, because the inspector is only requiring the minimum.

Never go with the minimum.)

Mitigation can be during or after an event

(a better reaction to an event is a form of mitigation).

But generally, mitigation is about preparation, not response.

Page 318 of the textbook includes insurance as part of mitigation planning.

However, considering the following statement in the textbook on page 331, is insurance a valid part of

mitigation?

“The policy failures include a system of flood insurance and post-disaster aid that encourages people to live in

coastal hazard areas and rewards politicians, developers, businesses, and individuals for rebuilding

previously flooded areas.” (page 331)

According to the textbook, Dauphin Island was ‘re-built’ several

times within a decade. (page 365)

How do politicians get rewarded?

Be rewarding foolish people who run to the government for help.

< Let’s face it, Folly Island is named that way for a reason. >

March, 2013 news item (I didn’t spend the money to buy the article on line):

Environmental groups compromised on their opposition to rebuilding a badly eroded ‘groin’ on . . . . . Folly Island.

What are groins suppose to do? Capture long-shore driven sand to create a beach to catch tourists and their money.

Groins often fail.

Politicians have a ready reason to spend their grandchildren’s money to get votes. People who rebuild

thereby believe that the government supports rebuilding in hazardous places.

Mitigate Prevent

Insure Replace

Which approach do you think is best?

Page 325 of the class textbook says:

“Katrina was the most anticipated natural disaster in American history.”

I think yes. The whole world watched on TV as Katrina developed, but thousands died anyway.

Would the Geologist’s concept apply to Hurricane Katrina in 2005?

Add wave height and wind-drive of waves.

Add heavy rain moving downstream as the surge is moving upstream.

Source:NOAA (NWS), National Hurricane Center, at www.nhc.noaa.gov/surge/

Could hurricane mitigation include personal awareness that an upstream river bridge could be flooded before houses at the beach get flooded?

Storm Surge Components

- Relatively low atmospheric pressure (__mb)

- High wind (caused by relatively low air pressure

- Heavy precipitation

- High waves (driven by wind)

???

Simpson-Saffir Scale for Hurricanes (1-5, for 74 mph and higher;

Category 5 hurricanes have wind speeds >155 mph)

Modified Mercalli Scale for Earthquakes (I-XII)

We still reference Magnitudes in terms of energy released and shaking; shoving a box of rocks = Mag. -3)

Enhanced Fujita Scale for Tornadoes (0-5, for wind speed 65mph and higher;

2013 Oklahoma F5 tornado exceeded 200 mph;a 1999 Oklahoma tornado exceeded 300 mph)

This is one of the tornadoes from the famous 1999 outbreak in Oklahoma.

Source: en.wikipedia.org/wiki/Tornadoes_in_the_United_States

US Hurricane Season: June 1 to November 30

US Tornado Season: (I start the tornado “clock” in January, but it may start as late as March in some areas, and ends . . . . well, whenever the tornadoes stop – which is practically never in the USA)

NOAA, NWS, archive, see Allred for archive info.

Unusual December tornadic storm with funnel clouds

Chapters 9-11(tornadoes, hurricanes & coastal processes)

Atmospheric Energy The power to do work

Two sources for Earth heat:- solar radiation

- magmatic (radioactive decay)

Water is an energy transfer substancewater is in almost everything: ice, liquid, vapor

Water vapor is an efficient way to move energy

Distribution of water and energy are not “fair” – very un-equal (hemisphere of illumination)

So, earth processes move energy unequally – evaporate it and move it unevenly – air pressure and weather change

The BIG SIX:Solar energy is not “sense-able” when it arrives,

but converts to:1. heat – molecules agitated by energy

2. air pressure3. wind

4. evaporation (humidity -storing heat in water as vapor)5. condensation (clouds)

6. precipitation

Structure of the Atmosphere(troposphere, stratosphere, mesosphere, thermosphere)

1. air pressure declines with altitude:at sea level:

14.7 pounds per square inch or 1,013mb

2. temperature – declines with altitudeat sea level/standard day: 59°F

- standard lapse rate (5 degrees/1000 ft)

- adiabatic rate (3 degrees/1000 ft)

Why does humid air cool off more slowly (3°F per thousand feet)

than dry air (5°F degrees per thousand feet?

Because humid air contains hidden (latent) heat.

Vertical change in air pressure is strong and rapid for several miles upward and means

relatively little.However, horizontal change in air pressure from place to place is relatively quite small but has a huge effect on weather conditions.

700 mb

950 mb1013 mb

1013 mb

Contents of the AtmosphereN2 = 79%

O2 = 21%

O3 = ozoneCh4 = methaneCO = carbon monoxideCO2 = carbon monoxide (rising from 280 pm to about 400 ppm

PM = particulate matter (PM2.5, PM10)H2O = water vapor (1-4 percent by volume)

Oxides of Nitrogen and Sulfur (and others)

Permanent gases

Variable gasesCh4

Coriolis Force

Coriolis ForceDuring the few seconds that a homerun ball is in flight, the Earth will move a few inches.

Electromagnetic Spectrum

Higher energy levelLower energy level

Most of this energy is from the Sun. Short waves get in easily and then turn longer wave, making it harder to get out – global warmth (and warming?)

Earth atmospheric energy balance:For every 100 energy units that come in,

100 units must leave

radiation IN (mostly shortwave),

reflection (31 solar ‘units’)

absorption (69 solar ‘units’)

convection & conduction

re-radiation OUT (mostly long wave)

Water has a huge effect on what happens to energy on Earth:

- water holds energy as heat, releases heat, absorbs heat, reflects energy,

transfers energy.

- Water vapor is the highest energy state of water, and is a very convenient

way of moving energy – by wind

Three States of WaterVapor – high energy storage (lose heat to change state)Liquid – moderate energy storageSolid (ice) – lower energy storage (add heat to change)

Even at 100 F degrees below zero, water contains large amounts of energy – absolute zero is more than 400 F degrees below zero.

So, even snowy blizzards and ice storms are still highly energetic storms, by containing large amounts of heat (relatively speaking).

Adiabatic process

cooling by evaporation of water – hide heatre-warming by condensing water – bring heat back

Consider the “swamp cooler”

An evaporative cooler ‘hides’ heat by turning it into humidity. That works well for temperatures in the middle.

For extreme temperatures (hot or cold) humidity just makes us feel worse.

So, swamp coolers are economical and efficient for the ‘room temperatures that we enjoy – about 70 F.

So . . . if evaporation is the process of hiding heat and water in the air, then condensation

is the process of bringing it back.

Whenever you see a cloud form, you can be sure that vapor is turning back into liquid

water, so heat is being released along with the hidden water.

So, a cloud forming in the sky is a warming event, the opposite of evaporation.

Latent heat and swamp coolers(hiding heat by evaporation – a cooling process)

To begin, evaporation requires energy, so heat becomes hidden or ‘latent’ in the air

The result of evaporating water is:

- humidity level goes up;- heat becomes hidden or ‘latent’

The price of evaporation is that air temperature goes down.

The problem with ‘hiding’ heat in humidity is that when the heat

comes back out of ‘hiding’ through condensation, severe storms can

result as ‘warm air rises’.

Rising air provokes high wind, rainy, lightning, storm surge, hail,

etc.

Evaporation makes air more humid

In theory, 100% humidity means that the air cannot hold any more moisture.

For class discussion, we can say that maximum humidity means that the “bucket is full.”

Humidity is always measured as relative –

How much water is in the air compared to how much could be in the air.

The hotter the air, the more capacity it has to hold evaporated water.

In a purely theoretical way, we can compare air temperature to capacity for humidity.

To keep it simple, let’s say a hot day at 100°F day has a capacity to hold 10 gallons of evaporated water (humidity).

A cool day at 60°F has a water vapor capacity of just six gallons of humidity.

As air rises it cools, so the ‘bucket’ size goes down.

Stormy weather involves rising air that is cooling down by decompressing as it rises to where air pressure is less.

As air decompresses, it cools down, making it easier for the humidity ‘bucket’ to overflow.

So, clouds pop out when air is forced to rise, decompress and cool down. The ‘bucket’ overflows when air temperature drops below the ‘dew point.’

5/5 or 6/6 or 4/4 all represent “full bucket.”

Let’s suppose air is rising orographically (over a real mountain).

As air rises it decompressesAs it decompresses it cools downIf it cools enough the ‘bucket’ overflowsThe air has reached ‘dew point’ saturation or ‘condensation level.’

4/2

4/4

4/6

4/8

4/10Notice that the ‘bucket’ size goes down as the air rises and cools down.

4/4 = 100% humidity

“dew point” ‘bucket’ Is full

50% humidity

40% humidity

67% humidity

“Dew Point” or ‘condensation level’ is the altitude in the sky where air temperature is too cold to hold the

amount of moisture available.

A cloud forms, and then rain or snow may begin. The humidity ‘bucket’ has over-flowed, because its capacity

to hold humidity has dropped below the water in it.

The air has become ‘saturated’ - - the ‘bucket’ is over-flowing because it is relatively too cold to hold the

moisture that it did hold before it rose in the sky and cooled down by decompression.

So, the weather report is always about relative humidity – how much water is in the air, compared to how much capacity.

Saturation at 100°F is like 10/10.Saturation at 60°F is like 6/6.

In both cases, the ‘bucket’ of air is ‘full’ of water – 100% relative humidity.

Ok, let’s look at an example of air rising and falling.

Near the Equator solar energy evaporates ocean water to create humidity. That buoyant air rises, decompresses, cools and then rains.

Rising air represents LOW atmospheric pressure.

The humidity ‘bucket’ fills up and overflows – rain.

Hadley CellsThe rise and fall of air and moisture for storminess

Humid air near the Equator rises and then precipitates.

Four kinds of stormy weather

orographicconvectiveconvergent

frontal – wedge

All of these involve rising air, which cools, condenses (releases heat) and then may keep

rising.

The natural rise of humid air near the Equator is an example of a convective

storm.

Air rising over a mountain is orographic storminess.

A frontal/wedge storm is warm/wet air rising over cool/dry air - - more push

and more violent weather.

In a frontal/wedge process, enough heat is stored in water vapor to rise rapidly over

cooler/dryer air.

A severe storm can develop:

the faster condensation occurs, the faster air warms itself; the faster air warms the

faster it rises. The faster it rises, the fast it decompresses, cools down and condenses

out more water . . . . and more heat.

OrographicAir rising up a mountain

air movesair evaporates water

air moves moreair rises

air decompressesair cools

air condensesprecipitation may occur