# Presentation: 790958

## Hurricanes, clouds & the water cycle

***Hurricanes, clouds & the water cycle***

**Tim Marchok**
**NOAA/Geophysical Fluid Dynamics Laboratory**
**timothy.marchok@noaa.gov**

**Sol Feinstone Elementary School**

**4****th**** Grade Class**

**December 20, 2006**

## Hurricanes:  What we’ll talk about

**Hurricanes:  What we’ll talk about**

- What hurricanes are and where they form
- How hurricanes work
- How hurricanes cause damage
- How the water cycle relates to hurricanes
- How we forecast hurricanes

## “Hurricane” is a specific name for storms in the Atlantic Ocean.  In general, these storms are known as “tropical cyclones”:
Tropical depression:	 winds < 39 mph
Tropical storm:	   winds < 74 mph
Hurricane:	   winds > 74 mph

- A hurricane is an intense, rotating storm that forms over the tropical oceans.

- “Hurricane” is a specific name for storms in the Atlantic Ocean.  In general, these storms are known as “tropical cyclones”:
- Tropical depression:	 winds < 39 mph
- Tropical storm:	   winds < 74 mph
- Hurricane:	   winds _>_ 74 mph

- ( gets named! )

## - Atlantic and Eastern Pacific Oceans  (“hurricanes”)- Western North Pacific Ocean  (“typhoons”)- South Pacific and Indian Oceans  (“cyclones”)

- Where do tropical cyclones form?

- (10)

- (26)

- (14)

- (15)

- (5)

- (9)

- (nn)  Number of storms per year

## Hurricanes:  What we’re talking about

**Hurricanes:  What we’re talking about**

- What hurricanes are and where they form
- How hurricanes work
- How hurricanes cause damage
- How the water cycle relates to hurricanes
- How we forecast hurricanes

## Why are the winds so strong in a hurricane?

- Winds always move from areas of higher pressure to areas of lower pressure.  The bigger the difference between the high and low pressure, the stronger the winds.

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- The winds from Hurricane Fabian battering Bermuda on September 5, 2003.

## What causes the winds to rotate around a hurricane?

- Hurricane Isabel making landfall on September 18, 2003

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- The **Coriolis Effect**:  A change in the direction of moving objects due to those objects moving on a rotating, round planet.

## How is a lawn mower like a hurricane?

- Gas provides the fuel for the mower’s engine

- The engine uses the fuel to do some work and move the grass-cutting blade

- The starter rope and spark plug are the “triggers” for making the mower start

- Exhaust fumes are expelled out away from the engine

## The hurricane heat engine: how it works

**3.** Having lost most of its heat and energy, the air now moves outward away from the center of the storm in the cooler, higher levels of the atmosphere (**the exhaust**).

- In strong hurricanes, an eye forms in the center.  Here, the air is moving downward and the region is generally free of clouds.

**2.** The warm, humid air rises in thunderstorms surrounding the eye, supplying the fuel that helps strengthen the** **storm and intensify the winds (**the work**).

**1.** As air rushes into the hurricane’s low pressure center, the air picks up heat and moisture (**the** **fuel**) from the warm ocean surface.

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## ...But where’s the trigger?(where is the hurricane’s “starter rope” ???)

- Hurricanes don’t just form out of thin air.  They usually grow from clusters of smaller thunderstorms that move across the oceans.

- Hurricane Frances (2004)

## ...show movie “storms_2004_wv_mini.mov” to show how storms develop from clusters of smaller thunderstorms, and to show how some clusters do in fact organize and strengthen into tropical cyclones while others never get their act together....

## Hurricanes:  What we’re talking about

**Hurricanes:  What we’re talking about**

- What hurricanes are and where they form
- How hurricanes work
- How hurricanes cause damage
- How the water cycle relates to hurricanes
- How we forecast hurricanes

## The triple threat of damage from a hurricane:

**Wind Damage**:  Wind gusts can approach 200 mph in the strongest hurricanes.
**Storm Surge**:  The winds of a hurricane pile up ocean water that can flood coastlines with water levels up to 30 feet higher than normal.
**Rainfall Flooding**:  Hurricanes can drop huge amounts of rain in a very short time, even inland far from where the storm made landfall.  Over the past 30 years, 9 out of every 10 fatalities in tropical cyclones have been due to drowning from inland flooding.

## Wind Damage examples

- A 1x4 board of wood was pierced through a palm tree by Hurricane Andrew’s winds in August, 1992.

- A mobile home park near Miami, FL was completely destroyed by Hurricane Andrew in August, 1992.

- An historic home along the Gulf Coast before and after the passage of Category 5 Hurricane Camille in August, 1969.

## Storm Surge examples

- Storm surge from Hurricane Carol completely inundates a yacht club in August, 1954.

- Apartment building in Pass Christian, Mississippi before and after the passage of Category 5 Hurricane Camille in August, 1969.  Thirty-two people ignored warnings and stayed for a “hurricane party”.  Only two survived.

- Hurricane Katrina’s 30-foot storm surge obliterated every home within several blocks of the shoreline in Pass Christian and Waveland, Mississippi.

## Hurricanes:  What we’re talking about

**Hurricanes:  What we’re talking about**

- What hurricanes are and where they form
- How hurricanes work
- How hurricanes cause damage
- How the water cycle relates to hurricanes
- How we forecast hurricanes

## Hurricanes and clouds

- Clouds make up the structure of a hurricane...

- Clouds surrounding the eye of  Hurricane Katrina

- ...but what makes up a cloud?

## Making a cloud in a bottle

- What are clouds made of?
- How do clouds form?
- Why are clouds often found so high in the sky?

## What’s going on in the bottle?

- What was the pump doing to the inside of the bottle?
- What happened when we uncovered the air release hole on the stopper?
- Was there a big difference in the cloud that formed before & after the match was dropped in?  Why?

## Clouds in the real world

- How is the atmosphere like a big stack of pancakes?

- Air particles closest to the ground feel the full pressure, or weight, of the atmosphere above.

## How a cloud forms

**Water evaporates and water vapor molecules rise into the air**

**As the air rises higher in the atmosphere, it expands and cools in the lower pressure**

**As the air cools to its condensation point, water condenses on particles and a cloud forms**

_**How a cloud forms**_

## Hurricanes and the Water Cycle

**Evaporation and Condensation:**
- Warm ocean water is the fuel for hurricanes.  Massive amounts of water are evaporated from the ocean surface and condensed into the clouds of a hurricane.

## Hurricanes and the Water Cycle

**Precipitation:**
- Does enough rain fall from a hurricane to fill a backyard swimming pool?

- How about 10?

## Hurricanes and the Water Cycle

- Hurricane Ivan (2004)

- Amount of rain from Hurricane Ivan:  22 trillion gallons
- (or about 573,000 backyard swimming pools)

## Hurricanes and the Water Cycle

**A beneficial effect of hurricanes**
- These potentially damaging storms can often bring much-needed rain to areas that are otherwise very dry in the summer months

## Hurricanes:  What we’re talking about

**Hurricanes:  What we’re talking about**

- What hurricanes are and where they form
- How hurricanes work
- How hurricanes cause damage
- How the water cycle relates to hurricanes
- How we forecast hurricanes

## Forecasting a hurricane’s track and intensity

- 1. Observations: Measuring the atmosphere

- Before we can predict what a storm will do in the future, we need to know what the storm and the atmosphere look like right now.

_**Radiosondes:**_ These instruments are attached to weather balloons and transmit temperature, humidity and wind data back to the ground.  These balloons are launched globally twice a day.

_**Surface:**_** **At thousands of weather stations across the globe, observers report weather conditions every hour.

_**Satellites:**_** **Numerous satellites gather data on clouds, moisture and ground and sea surface temperatures.

_**Aircraft:**_** **Commercial aircraft regularly report weather data.  In addition, Air Force and NOAA “Hurricane Hunter” aircraft penetrate hurricanes in order to gather valuable data on the storms.

- Two NOAA P3 “Hurricane Hunter” aircraft

- View from a Hurricane Hunter aircraft inside the eye of Hurricane Isabel while a category 5 storm.

## On board a recon flight into Hurricane Rita....

## On board a recon flight into Hurricane Rita....

## On board a recon flight into Hurricane Rita....

## Forecasting a hurricane’s track and intensity

- 2. Running a computer model

- A supercomputer is needed to quickly solve the complex equations that describe the motions of the atmosphere and the storm in particular.

- A graphical snapshot from a GFDL Hurricane Model forecast for Hurricane Floyd, September, 1999

## 3-D animation of a GFDL Katrina forecast

## Forecasting a hurricane’s track and intensity

- 3. Making heads or tails of all the model forecast data

- Sometimes the models agree with each other...

- This plot shows the computer model track forecasts for Hurricane Katrina issued almost 3 days before she made landfall.  The fact that the models agreed so well with one another made it relatively easy for the National Hurricane Center to forecast her landfall location.

- In this case, the forecast at this particular time for Hurricane Kate became a difficult one for the National Hurricane Center because the different computer model forecast tracks varied so wildly.

- ...and sometimes they don’t!

## Web links

- National Hurricane Center:   _[http://www.nhc.noaa.gov/](http://www.nhc.noaa.gov/)_
- Hurricane FAQ page (an excellent resource for any questions related to hurricanes):  _[http://www.aoml.noaa.gov/hrd/tcfaq/tcfaqHED.html](http://www.aoml.noaa.gov/hrd/tcfaq/tcfaqHED.html)_
- Wikipedia (lots of excellent descriptions on hurricanes and related info):  _http://en.wikipedia.org_
- Tornado FAQ page (another excellent resource): _[http://www.spc.noaa.gov/faq/tornado/](http://www.spc.noaa.gov/faq/tornado/)_
- Philadelphia / Mount Holly National Weather Service office:  _[http://www.erh.noaa.gov/er/phi/](http://www.erh.noaa.gov/er/phi/)_
- The Weather Underground (There is a link on this page to “Computer Models”, which will show you the latest track forecasts from various models): _[http://www.wunderground.com/tropical/](http://www.wunderground.com/tropical/)_
- Unisys tropical weather site (good info on both current and past hurricanes):  _[http://weather.unisys.com/hurricane/](http://weather.unisys.com/hurricane/)_
- University of Wisconsin archive of 2005 season images and movies:  _[http://](http://cimss.ssec.wisc.edu/tropic/archive/atlantic.html)__[cimss.ssec.wisc.edu/tropic/archive/atlantic.html](http://cimss.ssec.wisc.edu/tropic/archive/atlantic.html)_
******* For the next 30 days, this talk can be found under:
- ftp://ftp.gfdl.noaa.gov/pub/tpm/sfe/

## Washington Crossing Bridge

- August, 1955

- September 19, 2004

- Photo copyright: Tim Marchok, 2004

## The end.

## Outline

- What hurricanes are and where they form
- How hurricanes work
- How hurricanes cause damage
- How hurricanes differ from tornadoes
- How we forecast hurricanes
- Hurricanes and climate
**Hurricanes that have affected NJ and PA**** **

## Hurricanes Carol and Hazel

- August & October, 1954

- Hurricane Carol caused $460 million in damage and was responsible for 60 deaths on the U.S. East Coast

- Hurricane Hazel produced the strongest winds ever officially recorded in Philadelphia (94 mph)

- Storm surge from Hurricane Carol pounds the New England Coast

## Hurricanes Connie and Diane

- August, 1955

- Floods from the storms affected Yardley, washing out the Yardley-Trenton Bridge.  Fifty other bridges along the Delaware River were either damaged or destroyed.

- Flooding of the Delaware River at the Washington Crossing Bridge, August, 1955.

- The 2 storms hit within a week of each other, causing record rainfall and flooding, killing 180 people (90 along the Delaware River) and causing $680 million in damage on the U.S. East Coast.

## Hurricane Agnes

- June, 1972

- The storm stalled over northern Pennsylvania as a weakened tropical depression, leading to record rainfall amounts and disastrous flooding.

- Costliest natural disaster in Pennsylvania history ($2.1 billion in damage)

- 48 deaths in Pennsylvania from the flooding (122 total in the United States)

## Hurricane Floyd

- September, 1999

- Hurricane Floyd dumped 8-13 inches of rain in parts of the Philadelphia suburbs

- Eight people in southeastern Pennsylvania drowned in the flooding from Hurricane Floyd.

- In total, Floyd caused more than $4 billion in damage in the U.S.

- Satellite image of Hurricane Floyd making landfall in North Carolina, September 16, 1999

- Flooding of the Raritan River near Flemington, NJ, in the aftermath of Hurricane Floyd.

## The Saffir-Simpson Scale: A method for categorizing hurricanes based on wind speed

|  | Category 1 | Category 2 | Category 3 | Category 4 | Category 5 |
| --- | --- | --- | --- | --- | --- |
| Wind
speed (mph) | 74-95 | 96-110 | 111-130 | 131-155 | >155 |
| Storm 
surge (ft) | 4-5 | 6-8 | 9-12 | 13-18 | >18 |
| Damage 
description | Minimal | Moderate | Extensive | Extreme | Catastrophic |

## How are hurricanes different from tornadoes?

|  | Hurricanes | Tornadoes |
| --- | --- | --- |
| Where they form | Hurricanes form over warm water in the tropical oceans and develop best when far from the jet stream. | Tornadoes form over land and form within storms that are often very close to the jet stream |
| How big they are | Up to several hundred miles wide | No more than 1⁄4 mile wide |
| How long they last | Average of 9 days (up to 3 weeks) | No more than an hour |
| How strong the winds are | Less than 200 mph | Up to 300 mph |
| Occurrences per year | An average of 10 tropical storms in the Atlantic Ocean | In the United States, 800-1000 |
| Advance warning from
forecasters | Several days | No more than 15-30 minutes |

## Forecasting a hurricane’s track and intensity

- 2. Running a computer model

- A supercomputer is needed to quickly solve the complex equations that describe the motions of the atmosphere and the storm in particular.