Just-in-Time Lecture Hurricane Ali Ardalan, Ronald E. LaPorte, Eugene Shubnikov, Faina Linkov, Mehdi Russel & Eric K. Noji super

Just-in-Time Lecture

Hurricane

Ali Ardalan, Ronald E. LaPorte,

Eugene Shubnikov, Faina Linkov, Mehdi Russel

& Eric K. Noji

www.pitt.edu/~super/

What is the Disaster Supercourse?

http://www.pitt.edu/~super1

Mission Statement:

The Global Health Network

Disaster, Network for Hurricane

is designed to translate the best

possible scholarly information

from leading researchers to

educators worldwide.

What is a JIT lecture?

http://www.pitt.edu/~super1

Lecture objectives:

To provide the best possible

information about the science of

Hurricane

To learn how the science can help

prepare us for primary &

secondary

prevention consequences of

Hurricane

Origin of the word “Hurricane”

HURRICANE derived from ‘’Hurican’’,

the Carib god of evil !!Glossary of Meteorology

Carib god ‘’Hurican’’ was derived from Mayan

god 'Hurakan', one of their creator gods, who

blew his breath across Chaotic water &

brought forth dry land & later destroyed men

of wood with a great storm and flood .

Hurricane at a glance!

A tropical storm with 74 mph speed

winds Hurricane winds blow in a large

spiral around a relative calm center

known as the “Eye."

The “Eye" is generally 20 to 30 miles

wide & the storm may extend

outward 400 miles.

Hurricane at a glance!

A single hurricane can last for

> 2 weeks over open waters

Peak months: August & September

Hurricane season: 1st June-30th

November

Basic terminology in hurricanes:

Sustained wind:

Long lasting wind, reporting based on:

1 min average time in Atlantic & NE Pacific

10 min average time in rest of the world

Maximum sustained wind:

The highest 1 min “Surface winds” within

system circulation

Basic terminology in hurricanes:

Gusts

3-5 seconds wind peak

20-25% > 1 min sustained wind

Basic terminology in hurricanes:

Storm surge: Onshore rush of sea or lake water caused by

the high winds associated with a land falling

cyclone and secondarily by low pressure of

the storm

Be careful:

Storm surge & Storm tide are

different !

Hurricane Anatomy

EYE:

Centre of a hurricane characterized by a

roughly circular area of light winds & rain-free skies & lowest pressure

Developed when the maximum

sustained

wind speeds exceed 78 mph

Ranged size: 5-60 miles (20 miles in

average)

Shrinking the eye, intensifying the storm

Hurricane Anatomy

EYE WALL:

Organized band of convection surrounding eye or the centre

Contains cumulonimbus

clouds, severest thunderstorms, heaviest precipitation and strongest winds

Hurricane Anatomy

Spiral rain bands:

Large bands of clouds & precipitation spiral

from the eye wall

Hurricane Anatomy

Moat:

Region between the eyewall & an outer

rainband, such as a secondary eyewall &

rainband

Relatively light rain region between rainband & eyewall

Environmental Condition for tropical cyclone formation

Warm ocean waters of at least 26.5 C (80 F)

Warm, humid air

Relatively moist layers near mid-troposphere (5

km)

Minimum distance of at least 500 km from

equator

Environmental Condition for tropical cyclone formation

Pre-existing near-surface disturbance with

sufficient vorticity & convergence

Low values (less than 23 mph) of vertical wind

shear between the surface & the upper

troposphere

Sequence of Hurricane formation:

Tropical Disturbance

Tropical Depression

Tropical Storm

Hurricane

1

2

3

4

123

4

Hurricane term:

o REGIONALLY specific names for a strong

“Tropical cyclone"Tropical cyclones with max. sustained winds of less than 39 mph with close circulationTropical cyclones with max. sustained winds of 39-73 mph

Tropical cyclones with sustained winds of 74 mph

• Tropical Depression

• Tropical Storm

• Hurricane

• Typhoon

• Severe tropical cyclone

• Tropical cyclone

REGIONALLY names of “Tropical cyclones” with winds of 74 mph

Hurricane N Atlantic Ocean, NE Pacific Ocean E of

dateline, or S Pacific Ocean E of 160E

Typhoon NW Pacific Ocean W of dateline

REGIONALLY names of “Tropical cyclones” with winds of 74 mph

Severe tropical cyclone

SW Pacific Ocean W of 160E or SE Indian

Ocean E of 90E

Severe cyclonic storm

The North Indian Ocean

Tropical cyclone The Southwest

Wind blows the clouds clockwise & start pulling up ocean water.

Then the bottom water moves counterclockwise.

Air sinks into the

centre (the eye).

More details about Hurricane formation (1)

Wind spins around the eye, where hurricane is the strongest.

As the wind flows higher it becomes weaker and flows clockwise.

More details about Hurricane formation (2)

Hurricane death

A mature hurricane is a well-oiled meteorological

machine, but disruption of the processes that

drive storm (interaction with land or colder air

feeding in) will begin to destroy storm, & the

disintegration of a hurricane is quick & dramatic.

Important death factors:

o Westerly winds

o Going over land as there is warm water

Cape Verde-type hurricanes

Atlantic basin tropical cyclones fairly close

(<1000 km) of Cape Verde Islands & then

become hurricanes before reaching Caribbean

Typical months: August &September

Frequency: Ranged 0-5, with an average of 2

Hurricane/Tropical Cyclone Intensity Scales:

Atlantic hurricanes ranking (Saffir-Simpson hurricane intensity scale)

Australian tropical cyclones ranking

Saffir-Simpson hurricane intensity scale

Cate

gory

Max. sustained 1 min. wind speed

Minimum surface pressure

Storm surge

Damage descriptor

mphmbm

174-95 >980 1.0-1.7 Minimal

296-110979-965 1.8-2.6 Moderate

3111-130964-945 2.7-3.8 Extensive

4131-155944-920 3.9-5.6 Extreme

5156 + >920 5.7 +Catastrophic

CategoryWindEffects

1Strongest gust less than 125 km/h

Negligable house damage. Damage to some crops, trees and caravans. Draft may drag

moorings .

2Strongest gust 125 - 170 km/h

Minor house damage. Significat damage to signs, trees and caravans. Heavy damage to some crops. Risk of power failure. Small craft may break moorings

3Strongest gust 170 - 225 km/hSome roof and structural damage. Some caravans destroyed. Power

failure likely .

4Strongest gust 225 - 280 km/h

Significant roofing loss and structural damage. Many caravans destroyed and blown away. Dangerous airborne debris.

Widespread power failure .

5Strongest gust More than 280 km/hExtremely dangerous with

widespread destruction .

Australian tropical cyclones ranking

Factors contributing in hurricane damages:

Distance from zone of maximum

winds

How exposed the location is

Building standards

Vegetation type

Resultant flooding

Major hurricane = Intense hurricane

Max. sustained surface winds: At least 111 mph

Category 3,4 and 5 on Saffir-Simpson scale

Cause > 83% of damages in the USA even

though account for only 21% of tropical

cyclone landfalls

HURRICANE WARNING:

Added to a hurricane advisory that sustained

winds

of ≥74 mph associated with a hurricane are

expected in a specified coastal area within ≤24

h.

Can remain in effect when dangerously high

water or

a combination of dangerously high water &

exceptionally high waves continue, even

though

winds may be less than hurricane force.

Is used to inform the public and marine

interests of

the storm's location, intensity, and movement.

HURRICANE WATCH

An announcement added to a hurricane

advisory that hurricane conditions pose

a

possible threat to a specified coastal

area

within 36 hours.

Is used to inform the public and marine interests of the storm's location, intensity, & movement.

Subtropical cyclone:

Low-pressure system in tropical or subtropical latitudes

cyclones

Radius of max. winds farther out (on order of 60-125

miles from

the centre) than what is observed for purely tropical

systems

Max. sustained winds no stronger than 74 mph

Classified by max. sustained surface winds:

> 37 mph : Subtropical depression

≥ 38 mph : Subtropical storm Transform to tropical cyclones in many times &

then Hurricane, like Hurricane Florence, Nov 1994 !

USGS Slide: Dr. Tom Songer

Hurricane direct related health hazard

Storm surge

High winds

TornadosFlooding

Hurricane direct related health hazard: High Winds

Energy of winds = wind velocity

squared

(E = V2)2 times wind speed

= 4 times destructive energy

Hurricane direct related health

hazard: High Winds

Intensity of a landfalling hurricane is

expressed in terms of categories that relate

wind speeds & potential damage

(Saffir-Simpson Scale)

Category 4 hurricane (131-155 mph winds)

causes 100 times damage of Category 1 storm!

Hurricane direct related health

hazard: Rainfall & Flooding

Responsible for 59% of the

deaths associated with tropical

cyclones in the US

Intense rainfall is not directly related to

wind speed. Some of the greatest rainfall

amounts occur from weaker storms that

drift slowly or stall over an area.

Hurricane direct related health hazard:

Rainfall & Flooding: NHC Preventive recommendations

When you hear hurricane, think inland flooding

Determine whether you live in a potential flood zone

If advised to evacuate, do so immediately

Keep abreast of road conditions through the news media

Move to a safe area before access is cut off by flood water

Do not attempt to cross flowing water. As little as 6 inches

of water may cause you to lose control of your vehicle

Develop a flood emergency action plan

Have flood insurance

Hurricane direct related health hazard:

Storm Surge

50 - 100 miles wide

4 - 6 feet for a minimal hurricane to

> 20 feet for the stronger ones

Hurricane direct related health hazard: Tornado

More intense hurricane, greater tornado threat

10% of hurricane related death in the US

Mostly within 24 hours after hurricane landfall

Mostly within 150 miles

of the coastline

Hurricane direct related health hazard: Tornado

Occurrence during morning & afternoon rather

than evening or night due to need for heat source

The Gulf of Mexico hurricanes produce more

tornadoes than Atlantic storms

Mostly occur within 30 miles of center of cyclone

Can reach up to 300 mph at a forward speed of 60 mph and are usually 100-300 yards wide

Hurricane: History of death & economical damages 1990-2003

DeathDamage ($)

Hurricane Andrew 19922326.5 billion

Tropical Storm Alberto 1994

30500 million

Hurricane Opal 1995593 billion

Hurricane Mitch 1998900040 million

Hurricane Floyd 199950-563-6 billion

Hurricane Keith 200024225 million

Tropical Storm Allison 2001

415 billion

Hurricane Iris 200131

Hurricane Isabel 2003173 billion

Hurricane Preparedness, Before Hurricane Season Stars (8 points):1) Plan an evacuation route

Contact the local emergency management office or

Red Cross chapter, & ask for the community hurricane

preparedness plan, including information on the safest

evacuation routes & nearby shelters.2) Learn safe routes inland Be ready to drive 20 to 50 miles inland to locate a safe place.

Have disaster supplies on hand: Flashlight & extra

batteries, Portable, battery-operated radio & extra

batteries, First aid kit & manual, Emergency food &

water, Non-electric can opener, Essential medicines,

Cash & credit cards, Sturdy shoes.

Hurricane Preparedness, Before Hurricane Season Stars (8 points):3) Make arrangements for pets

Pets may not be allowed into emergency shelters for

health & space reasons, so contact your local humane

society for information on local animal shelters

4) Make sure that all family members know how to

respond after a hurricane Teach family members how & when to turn off gas, electricity, & water

Teach children how & when to call police, or fire

department & which radio station to tune to for

emergency information

Hurricane Preparedness, Before Hurricane Season Stars (8 points):5) Protect your windows

Permanent shutters are the best protection. A

lower-cost approach is to put up plywood

panels. Use 1/2 inch plywood - marine plywood

is best - cut to fit each window. Remember to

mark which board fits which window.

Pre-drill holes every 18 inches for screws. Do

this long before the storm

6) Trim back dead or weak branches from trees.

7) Check into insurance

Hurricane Preparedness, Before Hurricane Season Stars (8 points):8) Develop an emergency communication plan.

In case family members are separated from one

another during a disaster (a real possibility during

the day when adults are at work & children are at

school), have a plan for getting back together.

Ask an out-of-state relative or friend to serve as

the "family contact." After a disaster, it's often

easier to call long distance. Make sure everyone in

the family knows the name, address, and phone

number of the contact person.

Make sure you are preparedMake sure you are prepared!!

http://www.fema.gov/hazards/hurricanes/whatshouldido.shtm#before

References:

We wish to express our

warm thanks to GDHNet

faculties and all groups that

contributed their valuable

materials.