Cyclone Larry 2006

Severe Tropical Cyclone Larry Category 5

Site contains materials © Copyright Commonwealth of Australia 2006, Bureau of Meteorology (ABN 92 637 533 532)
used with permission

..see also -- we were there! Earth Science Australia's exclusive photos! 
and see Tropical Cyclones   and see Origins of Extreme Weather


Summary
Track
Impact Details
Observations
Satellite Images
Radar Images
Rainfall
Impact Photos
Wave and Tide graphs

First hand accounts by those who experienced Cyclone Larry
Snakes and Sharks
Esther
Adrian
John 1
Tom
Kirsty
John 2
Robert
Dan

What is a Category 5 Cyclone?
How the Saffir-Simpson Scale for rating Cyclone Intensity was devised (interview)
Saffir-Simpson Scale for rating Cyclone Intensity
Comparison to the damage inflicted by an nuclear bomb
Cyclone Rating System used in Australia
International Definitions (Severe Tropical Cyclones, Typhoons and Hurricanes)

Economic impacts of the cyclone
Flooding
Affect of Cyclone Larry on Avocado Growers (press release)
How does Cyclone Larry compare to other cyclones?


Track of Tropical Cyclone Larry

© Copyright Commonwealth of Australia 2006, Bureau of Meteorology (ABN 92 637 533 532)

Summary

Severe Tropical Cyclone Larry crossed the tropical north Queensland coast near Innisfail during the morning of 20 March, 2006. Major damage to homes and other buildings was caused by Larry as well as extensive damage to local crops.

Larry was quite small in size (like Severe Tropical Cyclone Ingrid that crossed the coast near Cooktown in March 2005). Major damage was along the portion of coast between Cairns in the north and Cardwell in the south. Fortunately Larry crossed the coast on a neap tide, so the significant storm surge and effects of the waves only caused the sea level to exceed heighest astronomical tide in a few locations and resulted in only minor salt water inundation.

street damage Innisfail


Apart from Severe Tropical Cyclone Ingrid, Larry is the first severe tropical cyclone to cross the Queensland east coast since Rona in 1999 (which crossed near the Daintree River north of Cairns). The most damaging cyclone impacts on Queensland's east coast prior to Larry were:

Track

Severe Tropical Cyclone Larry began as a low pressure system over the eastern Coral Sea that was monitored by the Bureau of Meteorology from 16 March. It formed into a tropical cyclone in the early hours of 18 March, and proceeded on an almost due westerly track towards the Queensland coast, intensifying as it travelled. Larry became a severe tropical cyclone (category three or higher) at 10am on 18 March, and continued to intensify as it approached the Queensland coast, reaching Category 4 early on 19 March. Just before crossing the coast, satellite picture interpretation techniques indicated that Larry had an estimated intensity of Category 5. The eye of Larry crossed the coast near Innisfail between 6:20am and 7:20am on 20 March. Larry started to weaken after crossing the coast but maintained cyclone strength for several hundred kilometres inland until the early hours of 21 March. Ex-tropical cyclone Larry was further tracked as it moved into western Queensland to the north of Mount Isa.

high winds


Impact

Severe Tropical Cyclone Larry is the first severe tropical cyclone to cross near a populated section of the east coast of Queensland since Rona in 1999, and the effects of the winds on buildings were devastating. Townships affected by the northern and southern portions of the eyewall of the cyclone received the most damage, particularly Babinda and Silkwood, however all townships in the region were severely affected by the cyclone. The following table (using data from Queensland Department of Emergency Services and Emergency Management Australia) summarises the damage:

Location Damage
Mareeba / Eacham / Millaa Millaa 93 damaged properties
Babinda 80% of buildings damaged
Flying Fish Point 15% of homes damaged
Innisfail 50% of homes damaged
35% of private industry damaged
25% of Government buildings damaged (schools etc)
Etty Bay 40% of homes suffered roof damage
East Palmerston 70% of homes damaged
Silkwood worst affected location
99% of homes lost roofs or suffered structural damage
Kurrimine Beach 30% of homes damaged
15% of private industry damaged
El Arish 30% of homes damaged
50% of private industry damaged
Bingil Bay 30% of homes damaged
Mission Beach 30% of homes damaged
20% of private industry damaged
45% of caravan park damaged
South Mission Beach 20% of homes damaged
20% of private industry damaged
Jappoonvale Possible tornado damage

© Copyright Commonwealth of Australia 2006, Bureau of Meteorology (ABN 92 637 533 532)
used with permission

Electricity transmission to the areas above (as well as Cairns) was severely disrupted. Road and rail access to the region was also disrupted for several days due to flooding. In the northwest of the state, heavy rainfall from ex-Tropical Cyclone Larry caused several townships to be isolated for several days due to flooding. Food drops were required. Images of the flooding in the northwest of the state can be seen at the NASA Earth Observatory web site.

A significant storm surge was caused by Severe Tropical Cyclone Larry, with sea levels exceeding the predicted tide by 1.75m at Clump Point (at which point the instrument stopped recording prior to landfall), 1.76m at Cardwell and 1.54m at Mourilyan. Surges of greater than 0.5m were experienced at all recording stations from Cairns to Townsville. However predicted tides were approximately 1.5m below the Heightest Astronomical Tide (HAT) at the time of coastal crossing, so the total water level equalled of only just exceeded HAT by a few centimetres at Cardwell, Clump Point and Mourilyan. (Storm surge data provided by Queensland Environmental Protection Agency - further information can be found on the EPA website.)

Observations Summary (Last Updated 7April 2006)

Note: all times are AEST

The information shown below is preliminary only.

Initial investigations indicate that wind flows associated with Severe Tropical Cyclone Larry were complicated possibly by the steep terrain encountered at landfall. In some places there is also evidence of damage consistent with tornadoes being generated. Click here for a satellite image showing the explosive convection that occurred upon landfall (image from University of Wisconsin).

The closest official instrumented observation site was the Bureau of Meteorology's Automatic Weather Station(AWS) at South Johnstone. The maximum gusts are recorded in the table below. Images of the AWS (looking south) taken in 2002 before (41kb) TC Larry and the day after (81kb) TC Larry show that the nearby buildings remained largely unaffected consistent with the observed winds. However the distant hill has obvious tree damage and erosion indicating possibly much higher windspeeds.

The following images...
© Copyright Commonwealth of Australia 2006, Bureau of Meteorology (ABN 92 637 533 532)
used with permission

Sth Johnstone AWS (2002)

BEFORE CYCLONE: South Johnstone AWS (2002)
Click image to enlarge (41 KB)


Sth Johnstone AWS after TC Larry

AFTER CYCLONE: South Johnstone AWS 21/03/06
Click image to enlarge (81 KB)


Click to enlarge

Map of observation sites
Click image for current observations(external link)


Click to enlarge

Google-Earth image with placenames
Click image to enlarge (119 KB)

Innisfail Region Wind Observations
20 March 2006

  Innisfail (estimated winds only) South Johnstone Automatic Weather Station
3.30am 50 - 60 km/h from S-SSW 17 km/h from SW with gusts to 33 km/h
4.50am 120 km/h from S-SSW 20 km/h from SSW with gusts to 42 km/h
6.00am 180 km/h from S-SSW 63 km/h from S-SSW with gusts to 142 km/h
6.30am 200 km/h from S-SSW with gusts to 250 km/h 78 km/h from S-SSW with gusts to 128km/h
6.38am   81 km/h from S-SSW with gusts to 181 km/h
6.50am beginning of eye, calm winds 89 km/h from S with gusts to 139 km/h
7.20am end of eye 74 km/h from SE with gusts to 105 km/h
7.30am 200 km/h from N-NNE 83 km/h from E with gusts to 130 km/h
8.00am 250 km/h from N-NNE 93 km/h from ENE with gusts to 128 km/h
8.10am 290 km/h from N-NNE with gusts to 310-320 km/h 91 km/h from ENE with gusts to 124 km/h
8.30am 250 km/h from N-NNE with gusts to 290 km/h 91 km/h from ENE with gusts to 126 km/h
9.00am 210 km/h from NE with gusts 220-250 km/h 76 km/h from ENE with gusts to 124 km/h
10.00am 70 km/h from NE with gusts 100-120 km/h 54 km/h from ENE with gusts to 120 km/h
11.00am 50 km/h from NE with gusts 60-80 km/h 37 km/h from NE-ENE with gusts to 54 km/h
12 noon 40 km/h from NE with gusts 50-60 km/h 30 km/h from NE-ENE with gusts to 43 km/h

Maximum Measured Wind Gusts

Flinders Reef 114 knots / 211 km/h at 9.10pm 19 March 2006
Hamilton Island Airport 53 knots / 98 km/h at 10:58pm 19 March 2006
Alva Beach 43 knots / 80 km/h at 5.31am on 20 March 2006
Low Isles 41 knots / 76 km/h at 9:00am 20 March 2006
Green Island 59 knots / 109 km/h at 7:04am 20 March 2006
Cairns Airport 58 knots / 107km/h at 8:01am 20 March 2006
Mareeba 61 knots / 113 km/h at 8:39am 20 March 2006
South Johnstone 98 knots / 181 km/h at 6:33am and 6:38am 20 March 2006
Lucinda 59 knots / 109 km/h at 5:32am 20 March 2006
Bellinden Ker Tower 7 (elevation approx 1450m)* 159 knots / 294 km/h at 7:18am 20 March 2006
Ravenshoe Wind Farm** 100 knots / 187 km/h at 8:40am 20 March 2006
*CSIRO Land&Water
**Stanwell Corporation
© Copyright Commonwealth of Australia 2006, Bureau of Meteorology (ABN 92 637 533 532)
used with permission

Maximum Measured Sustained Winds

Low Isles 37 knots / 68 km/h at 9:00am 20 March 2006
Green Island 46 knots / 85 km/h at 7:04am 20 March 2006
Cairns Airport 29 knots / 54 km/h at 7:42am
Mareeba 40 knots / 74 km/h at 9:00am 20 March 2006
South Johnstone 48 knots / 89 km/h at 6:50am 20 March 2006
Flinders Reef 84 knots / 155 km/h at 9:10pm 19 March 2006
Cardwell 47 knots / 87 km/h at 6:00am and 9:00am 20 March 2006
Lucinda 44 knots / 81 km/h at 4:00am 20 March 2006

 © Copyright Commonwealth of Australia 2006, Bureau of Meteorology (ABN 92 637 533 532)
used with permission

Lowest Reported Pressure

Flinders Reef, 9:00pm 19 March 2006 973.1 hPa
South Johnstone, 6:56am 20 March 2006* 959.3 hPa

*Privately owned barometers have reported lower values, and are being investigated further.
© Copyright Commonwealth of Australia 2006, Bureau of Meteorology (ABN 92 637 533 532)
used with permission

Rainfall

24 hours to 9am 20 March 2006
273mm - Mourilyan Mill Alert (Johnstone River catchment)
230mm - Babinda (Mulgrave-Russell catchment)
230mm - Saltwater Creek Alert (Johnstone River catchment)
220mm - Bulgun Creek Alert (Tully River catchment)
213mm - The Boulders (Mulgrave-Russell catchment)
212mm - Jarra Creek Alert (Tully River catchment)
190mm - Sutties Creek Alert (Johnstone River catchment)
24 hr rainfall to 9am 20 March 2006
Rainfall to 9am 20 March 2006 AEST
Click to enlarge (16 KB)
24 hours to 9am 21 March 2006
169mm - Paluma Dam Alert (Upper Burdekin River)
149mm - Abergowrie Bridge Alert (Herbert River d/s Glen Eagle)
140mm - Elphinstone Pkt (Herbert River d/s Glen Eagle)
128mm - Bilyana Alert (Tully River catchment)
127mm - Bolinda Estate Alert (Tully River catchment)
121mm - Euramo Alert (Tully River catchment)
110mm - Koombooloomba Dam Alert (Tully River catchment)
24 hr rainfall to 9am 21 March 2006
Rainfall to 9am 21 March 2006 AEST
Click to enlarge (18 KB)
24 hours to 9am 22 March 2006
436mm - Gereta Station (Leichhardt River catchment)
279mm - Kamilaroi (Leichhardt River catchment)
230mm - Gunpowder (Leichhardt River catchment)

301mm - Sweeney Creek U/S Alert (Johnstone River catchment)
284mm - Bulgun CReek Alert (Tully River catchment)
289mm - Innisfail (Johnstone River catchment)
285mm - Murray Flats Alert (Tully River catchment)
275mm - Innisfail Wharf Alert (Johnstone River catchment)
258mm - Tung Oil Alert (Johnstone River catchment)
258mm - Euramo Alert (Tully River catchment)
248mm - Marco Street Alert (Johnstone River catchment)
240mm - Bilyana Alert (Tully River catchment)
237mm - Nerada Alert (Johnstone River catchment)
228mm - Corsis Alert (Johnstone River catchment)
225mm - Upper Murray Alert (Tully River catchment)
223mm - Tully Alert (Tully River catchment)
221mm - Tully Sugar Mill (Tully River catchment)
217mm - Jarra Creek Alert (Tully River catchment)
215mm - Cardwell (Tully River catchment)
206mm - Central Mill (Johnstone River catchment)
201mm - Bartle View Alert (Johnstone River catchment)
192mm - Topaz Alert (Johnstone River catchment)
24 hr rainfall to 9am 22 March 2006
Rainfall to 9am 22 March 2006 AEST
Click to enlarge (22 KB)
24 hours to 9am 23 March 2006
149mm - Kamilaroi (Leichhardt River catchment)
147mm - Gereta Station (Leichhardt River catchment)
100mm - Nardoo (Leichhardt River catchment)
24 hr rainfall to 9am 23 March 2006
Rainfall to 9am 23 March 2006 AEST
Click to enlarge (21 KB)

Forecast Coastal Crossing Parameters (at 5:45am 20 March 2006)

Crossing location Innisfail region
Category when crossing the coast 5 (estimated, subject to ground investigation)
Speed of movement 25 km/h to the west
Estimated Maximum Wind Gusts up to 290 km/h
Estimated Central Pressure 915 hPa
Estimated Storm Surge 2-3m between Mourilyan and Cardwell
Eye Radius 15-20 km
Radius of Maximum Winds 20-30 km
Radius of Very Destructive Winds 40-50 km
Radius of Destructive Winds 120 km

© Copyright Commonwealth of Australia 2006, Bureau of Meteorology (ABN 92 637 533 532)
used with permission

Satellite Imagery

Images from MTSAT-1R satellite
received and processed by Bureau of Meteorology
courtesy of Japan Meteorological Agency.

TC Larry - 20:33UTC - Australian view

Australia, 20/03/06, 6:30am AEST
(infra-red) Click to enlarge (1086 KB)


TC Larry - 21:33UTC - Queensland view

Queensland, 20/03/06, 7:30am AEST
(infra-red) Click to enlarge (1014 KB)


TC Larry - 20:33UTC - Larry at sunrise
Innisfail area, 20/03/06, 6.30am AEST
(Visible) showing explosive convection Click to enlarge (84 KB)*
*this image courtesy of University of Wisconsin (USA).

© Copyright Commonwealth of Australia 2006, Bureau of Meteorology (ABN 92 637 533 532)
used with permission


More satellite imagery (large files)

Just before landfall

before landfallLarge image is 3.7 megs!



Just after landfall

just after landfallLarge image is 4.7 megs!



  TC Larry - 128 km Cairns Airport Radar
Cairns Airport
20/03/06, 6:20am AEST
Click image to enlarge (33 KB)

TC Larry - 256 km Townsville(Mt Stuart) Radar
Townsville(Mt Stuart)
20/03/06, 6:20am AEST
Click image to enlarge (35 KB)

© Copyright Commonwealth of Australia 2006, Bureau of Meteorology (ABN 92 637 533 532)
used with permission



Cyclone Impact Images
Clicl image to open larger version

  TC Larry impact photo 1Innisfail State High School has reopened!
58 KB
TC Larry impact photo 2
66 KB
TC Larry impact photo 3
80 KB
TC Larry impact photo 4Mourilyan Sugar Mill will not open for 2006 crushing season
87 KB
TC Larry impact photo 5
123 KB
TC Larry impact photo 6banana crop destroyed no new bananas for 7-10 months, many casual jobs lost
138 KB
TC Larry impact photo 7
157 KB
TC Larry impact photo 8many without power 2+weeks
81 KB
TC Larry impact photo 9 World Heritage Rainforest blasted of leaves
136 KB
TC Larry impact photo 10
134 KB
TC Larry impact photo 11
75 KB
© Copyright Commonwealth of Australia 2006, Bureau of Meteorology (ABN 92 637 533 532)
used with permission 

 Wave and Tide graphs of Cyclone Larry


Cairns tide plot [ 12 kb]
Cairns wave plot [ 13 kb]
Cardwell tide plot [ 13 kb]
Clump tide plot [ 13 kb]
Location plot [ 10 kb]
Lucinda tide plot [ 13 kb]
Mackay wave plot [ 18 kb]
Mourilyan tide plot [ 13 kb]
Townsville tide plot [ 12 kb]
Townsville wave plot [ 12 kb]

Cairns tide plot [ 12 kb]

Cairns_tide_plot1.gif

Cairns wave plot [ 13 kb]


Cairns_wave_plot1.gif

Cardwell tide plot [ 13 kb]


Cardwell_tide_plot1.gif

Clump tide plot [ 13 kb]


Clump_tide_plot1.gif

Location plot [ 10 kb]


Location_plot1.gif

Lucinda tide plot [ 13 kb]


Lucinda_tide_plot1.gif

Mackay wave plot [ 18 kb]


Mackay_wave_plot1.gif

Mourilyan tide plot [ 13 kb]


Mourilyan_tide_plot1.gif

Townsville tide plot [ 12 kb]


Townsville_tide_plot1.gif

Townsville wave plot [ 12 kb]


Townsville_wave_plot1.gif

© Copyright Commonwealth of Australia 2006, Bureau of Meteorology (ABN 92 637 533 532)
used with permission

Snakes and Sharks by Kylie Camp

Major flooding in Queensland's north-west has led to sharks invading one rural property 80 kilometres inland.

Locals from the region, 200 kilometres north of Mount Isa, say the area around the Leichhardt River is having its worst floods since 1964.
Kylie Camp from Floraville Station says river levels that are normally 12 metres below the Leichhardt Falls are now 12 metres above that level.
She says the record flooding has now given sharks access to the station.
"I've never seen so many snakes in my life and also some sharks as well," she said.
"We do see sharks sometimes below the waterfalls that are normally here, probably just trying to get out of the fast moving current into somewhere quieter.
"This is the biggest recorded flood here I think - it's the first time I've ever seen such a thing."

Esther

It started off a bit windy for a few hours then all of a sudden it picked up like in an instant. The winds were really strong and small bits of debris were flying around. Before we knew it, Larry had upgraded to Category 5. Trees were uprooted and bending over. We were sure that our windows were going to smash as the force of the winds against them were increasing. There was also a lot of rain and it was scary. We had only got the side of Larry so imagine what Innisfail got. Our hearts go out to them. It's a miracle that no-one died.
Esther, Cairns, Australia

Adrian

We stocked up and prepared for a family night in the bathroom. As it happened Townsville got of very lightly and captured much needed rain. I feel there is a sting in the tail with a Cyclone Wati developing! Our thoughts are with those poor people in Innisfail.
Adrian, Townsville Nth Qld, Australia

John

We're just a little bit north of the swirly bit, we had been cut off for three days lest week because of torrential rains and floods, now it's the other way around, we have many friends down that way that we haven't heard from as yet but we are assured that there have been no fatalities. The fact that all out services have to come through that region is a little alarming though, thankfully we still have power, unlike last week! But, cyclone Wati is following close behind so the next 72 hours could be interesting. Hey, as they say up here... "hey, you wanted to live in the tropics!"
John, Cooktown, Australia

Tom Perry

Myself and a couple of friends are backpacking currently up the East coast of Australia, we are currently stuck on Magnetic island which is a few hundred kilometres south of Innisfail but all ferries were stopped yesterday meaning we have to stay here for a few more nights. Even though we are still quite far away the wind and rain was pretty dramatic last night. We spent yesterday evening packing all loose equipment from the hostel away and then sheltering in our dorms. It was quite dramatic.
Tom Perry, Ashford, Kent

Kirsty McCullough

We have been spared the worst. Until about 10pm last night we were expecting to be within the worst of the zones but a last minute shift moved the cyclone far enough north to only give us rain and gales. But our blessing has been the curse of others with awful pictures and stories coming through on ABC local radio of the sheer devastation. Yesterday was very surreal - the real calm before the storm, the intense preparation and then the watching and waiting foe something so unknown yet so inevitable. Very weird 24 hours. Now watching Cyclone Wati which seems to be following in the wake of Larry.
Kirsty McCullough, Townsville, Australia

John Stevenson

I live in Trinity beach, 30k north of cairns. It's 2pm and people are starting to get outside to clean up their gardens. In the northern suburbs we got off lightly with only a few road signs and trees down. I drove into cairns to see my daughter and the roads through the botanic gardens are like an obstacle course, with big trees and broken power lines everywhere. I saw little structural damage other than car ports and fences but everybody's garden is deep in broken branches and leaves. We have been told it could be several days before full electricity supply is restored but all in all we seem, at least where I have been, to have got off lightly.
John Stevenson, Cairns Australia

Robert White and James King

Our flight was forced to turn back today after reports of a massive cyclone in the Cairns area. We are both now stranded in Brisbane awaiting more news of the opportunity to travel up there. As soon as we get there we should be able to email some pictures of "The most devastating cyclone in decades"
Robert White and James King, Banbury, England

Dan

My sister is staying in Cairns while travelling, she just rang to say that it is raining heavily and the roads are covered in water and it is extremely windy and there is debris flying around everywhere. You can hear the roof rattling on the phone and she says that rain is being driven in through the windows.
Dan Murphy, UK

How the Saffir-Simpson Scale for rating Cyclone Strength was devised

The Saffir-Simpson scale was devised about 35 years ago by engineer Herbert Saffir and meteorologist Robert Simpson. At the time, Simpson directed the National Hurricane Center in Miami and Saffir ran his own engineering firm in neighboring Coral Gables.

Simpson and Saffir both chuckled when asked about the recent fame of their rating scale. But they also were gratified that their brainchild had found its way into popular speech.

"People are looking for yardsticks," Simpson said. "Our language has demonstrated the use of many expressions that started out to be used for one phenomenon, then were used to refer to many other things."

Saffir said he's "very pleased that the public is aware of the scale and can see the difference between a Category One and a Category Five storm. That's extremely important."

Planning Tool

Saffir and Simpson created the scale to help local relief agencies and emergency management officials better prepare for approaching hurricanes. Until recently, the scale was mostly known to meteorologists and officials at emergency management and relief agencies.

Simpson and Saffir each witnessed powerful hurricanes long before they devised the scale. Simpson watched a hurricane deliver a devastating blow to his hometown of Corpus Christi, Texas, in 1919. Although he was only six years old at the time, he still has vivid memories of that catastrophe.

In the summer of 1947, Saffir, a New York City native, took a job as a county engineer in Miami. Soon after he arrived, a pair of hurricanes put much of South Florida under water.

About 12 years later, Saffir had set up his own engineering firm when the United Nations commissioned him to write a report on providing low-cost housing in areas of the world that are subject to hurricanes.

As he worked on the report, Saffir realized that there were only two ways of categorizing hurricanes—major and minor.

"I worked up five scales [of hurricanes] based on a subjective description of the damage that could occur for each category," Saffir said.


Cyclone Categories

Saffir-Simpson Scale: Cyclone Intensity

 - note this scale is not used by the Bureau of Meterology in Australia

  • Category One

    Wind speeds: 74 to 95 miles an hour (119 to 153 kilometers an hour)
    Barometric pressure: No lower than 28.94 inches, or 980 millibars
    Storm surge: 4 to 5 feet (1.2 to 1.5 meters)
    Likely damage: Minimal. No significant damage to buildings. Damage will be mainly to unanchored mobile homes, trees, and shrubbery. There also will be some coastal flooding and minor damage to piers.
  • Category Two

    Wind speeds: 96 to 110 miles an hour (154 to 177 kilometers an hour)
    Barometric pressure: 28.50 to 28.92 inches, or 965 to 979 millibars
    Storm surge: 6 to 8 feet (1.8 to 2.4 meters)
    Likely damage: Moderate. Damages to some roofs, doors and windows. Considerable damage to trees, shrubbery and mobile homes. Some flooding damages to piers and small craft. Some small craft may break their moorings.
  • Category Three

    Wind speeds: 111 to 130 miles an hour (179 to 209 kilometers an hour)
    Barometric pressure: 27.91 to 28.47 inches, or 945 to 964 millibars
    Storm surge: 9 to 12 feet (2.7 to 3.7 meters)
    Likely damage: Extensive. Some damage to small residences and utility buildings. Mobile homes destroyed. Coastal flooding destroys smaller structures, and larger structures damaged by floating debris. Flooding may occur far inland.
  • Category Four

    Wind speeds: 131 to 155 miles an hour (211 to 249 kilometers an hour)
    Barometric pressure: 27.17 to 27.88 inches, or 920 to 944 millibars
    Storm surge: 13 to 18 feet (4 to 5.5 meters)
    Likely damage: Extreme. Heavy damage to many residences, with roofs completely destroyed on small residences. Major erosion of beaches. Flooding may occur far inland.
  • Category Five

    Wind speeds: Exceeding 155 miles an hour (249 kilometers an hour)
    Barometric pressure: Lower than 27.17 inches, or 920 millibars
    Storm surge: More than 18 feet (5.5 meters)
    Likely damage: Catastrophic. Roofs completely destroyed on many residences and larger buildings. Some buildings completely destroyed. Major flood damage to lower floors of buildings near the shore. Massive evacuation may be required. Flooding may occur far inland.

Cyclone Category in Australia


Tropical cyclone categories

© Copyright Commonwealth of Australia 2006, Bureau of Meteorology (ABN 92 637 533 532)
used with permission


International Definitions (Severe Tropical Cyclones, Typhoons and Hurricanes)

Tropical cyclones can be defined in different ways in elsewhere in the world.  Often news reports from the United States or Asia will refer to hurricanes or typhoons. These are all tropical cyclones, but with different names.  While the category definitions are not identical, the following provides an approximate guide for comparison

Australian
Name
Australian
Category
US US Saffir-Simpson Category Scale NW Pacific Arabian Sea /Bay of Bengal SW Indian Ocean South Pacific
(East of 160E)
Tropical
Low
- Tropical Depression - Tropical Depression Depression or 
Severe Depression
Tropical Depression Tropical depression
Tropical Cyclone 1 Tropical Storm - Tropical Storm Cyclonic Storm Moderate
Tropical Storm
Tropical Cyclone
(Gale)
Tropical Cyclone 2 Tropical Storm - Severe
Tropical Storm
Severe
Cyclonic Storm
Severe
Tropical Storm
Tropical Cyclone
(Storm)
Severe Tropical Cyclone 3 Hurricane 1 Typhoon Very Severe
Cyclonic Storm
Tropical Cyclone Tropical Cyclone
(Hurricane)
Severe Tropical Cyclone 4 Hurricane 2-3 Typhoon Very Severe
Cyclonic Storm
Intense
Tropical Cyclone
Tropical Cyclone
(Hurricane)
Severe Tropical Cyclone 5 Hurricane 4-5 Typhoon Super
Cyclonic Storm
Very Intense
Tropical Cyclone
Tropical Cyclone
(Hurricane)

© Copyright Commonwealth of Australia 2006, Bureau of Meteorology (ABN 92 637 533 532)
used with permission


Comparison to the damage inflicted by an nuclear bomb

Tropical Cyclone Larry hit Innisfail, Australia, on Monday morning, ripping the roofs off buildings and damaging 55 percent of the homes in the city. "It looks like an atomic bomb hit the place," said the mayor, and city residents repeated his claim. Could Larry's 180 mile-per-hour wind gusts cause as much damage as an atomic bomb?

It depends how you calculate damage. A Category 4 cyclone like Larry might level buildings over an area of 2,500 square miles. (A hurricane is just what we call a tropical cyclone that originates in our part of the world.) It would take a 10-megaton nuclear weapon to inflict damage over such a wide area. By comparison, the atomic bombs dropped on Hiroshima and Nagasaki were only about 15 and 21 kilotons. (There are 1,000 kilotons in a megaton.) It's a little tricky to compare the two, since a nuke would obliterate everything near to the site of the explosion and inflict less damage as you moved farther away. A hurricane, on the other hand, would cause less severe damage, but the damage would be more uniform and over a larger area.

You can get a better sense of how the two compare by looking at the devastation caused by a nuclear weapon at various distances from the explosion. Then, it's possible to figure out what kind of tropical storm would cause a similar amount of damage at each distance. Savannah, Ga., commissioned this kind of analysis in advance of the G-8 meetings of 2004. Part of the study looked at the structural damage caused by a 25-kiloton nuclear explosion. At a radius of three miles, the damage would be equivalent to that caused by a piddling hurricane with wind speeds averaging 80 mph. At half that distance from the blast, the effects would be more like a Category 5 storm with 160 mph winds.

Nuclear explosions can destroy a city with thermal radiation and a wave of kinetic energy. They also generate high-speed winds that cause damage in much the way a hurricane might. The blast wave consists of an expanding line of very high pressure (called "overpressure") that draws gusting winds in its wake. The wave of overpressure sweeps past structures very quickly, followed by winds that can crash into them at hundreds of miles per hour. Thermal radiation can also produce high winds by igniting flammable materials and setting off a mass fire. The rising heat from a mass fire causes cool air to rush in from the periphery at hurricane velocities. A real hurricane works in a similar way.

Nuclear blast-winds don't affect buildings in quite the same way as hurricane winds of the same speed. The nuclear blast-wind looks like a strong pulse, or gust, rather than the sustained winds of a hurricane. In that sense, it causes damage more like a tornado would—by hitting a building with high intensity for a short period. On the other hand, blast winds generally hit a building from one direction like hurricane winds. Tornado winds cause extra damage by twirling around as they hit.

Flooding

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Affect of Cyclone Larry on Avocado Growers


Avocados Australia, peak industry body said cyclone Larry had caused devastation to one of the Australia’s largest avocado production areas and to the lives of hundreds of avocado growers.
The main growing areas in North Queensland have been destroyed in the middle of their harvest period. Resulting is large losses for growers in what was looking to be one their most successful seasons in many years.
Over $15 million worth of crop was lost in just a few short hours. The North Queensland avocado crop was currently supplying 80% of the fruit in the market. The next production area to begin harvesting is Bundaberg.  
 Avocados Australia, Chief Executive Officer Antony Allen said initial reports indicated the majority of production areas had been devastated.
“Communities in producing areas will be severely effected in what was the height of the harvesting and packing period for avocado businesses”, he said.
 “We understand some growers have lost their entire avocado crop and large numbers of trees have been completely up-rooted. It could be up to five years before the North Queensland industry is capable of recovery.”
“The North Queensland industry and community will require long term assistance to be able to rebuild and we will work with the Queensland Department of Primary Industries & Fisheries and our fellow peak industry bodies on what can be done to help rebuild the North Queensland horticulture industry.”
Banana growers website was unavailable


How does Cyclone Larry compare to other cyclones?

By Tim Arvier
National Nine News


The images coming out of Innisfail have shocked Australians. Houses have been destroyed, crops obliterated and livelihoods shattered. Many have called Cyclone Larry one of the biggest ever to hit Australia. But how does it actually compare with other cyclones which have struck our shores?

Below is a list of some of the most ferocious cyclones that have lashed Australian towns and cities. We also compare these with Hurricane Katrina.

Cyclone Larry, March 2006.

After wreaking havoc in Innisfail, Larry has now weakened into a low pressure system and is not expected to be any further threat.

At its peak, the cyclone registered winds of up to 290km/h and was graded a category five, the highest possible grading for a cyclone.

While the economic damage may run into the hundreds of millions of dollars, amazingly, no one was killed.

Cyclone Mahina, March 1899.

The most deadly cyclone in Australian history, Mahina struck at Bathurst Bay near Cape Melville in Queensland.

It completely destroyed a pearling fleet, with over 400 people losing their lives.

Massive flooding affected many Aboriginal communities, with around 100 indigenous Australians thought to have perished.

Unfortunately no comprehensive documentation of Mahina's size or wind speeds exists.

Cyclone Ada, January 1970.

A category four cyclone, Ada struck holiday resorts on the Whitsunday Islands in north Queensland.

Fourteen people were killed and luxury yachts worth millions of dollars destroyed.

Widespread flooding also occurred between Bowen and Mackay.

Cyclone Tracy, December 1974.

Probably the most famous cyclone in Australian history, Tracy flattened Darwin on Christmas Eve 32 years ago.

Of a population of 43,000, 25,000 had their homes destroyed as Tracy scored a direct hit.

Sixty-five people were killed, 16 of them at sea.

Tracy's wind gusts recorded speeds of up to 250kmh and she was graded a category four.

She also dumped 195mm of rain on Darwin in under eight hours.

Cyclone Winifred, February 1986.

This cyclone also ravaged Innisfail. While it crossed the coast further south than Larry and was only a category three, it still managed to destroy 50 homes and damage hundreds of other large buildings around the town.

Three people died and millions of dollars worth of sugar cane and fruit crops were ruined.

Cyclone Bobby, February 1995.

Cyclone Bobby was graded a category four and passed the coast near the town of Onslow in Western Australia.

While it damaged many farms and houses, the biggest losses occurred at sea, where seven people were killed after their boats sank.

Cyclone Ingrid, March 2005.

Ingrid is infamous for threatening not only northern Queensland but also the Northern Territory.

It passed the Queensland coast north of the Lockart River, moved across the mainland into the Gulf of Carpentaria and then terrified residents in the Top End.

While Ingrid was an intense category five cyclone with wind speeds of almost 300kmh, it wasn't very large, which meant its severe impact was limited to what lay directly in its path.

Ultimately the cyclone passed wide of Darwin and although many rural properties were damaged, no fatalities were recorded.

Hurricane Katrina, August 2005.

While they have different names, hurricanes and cyclones are actually the same thing, also known as typhoons in southeast Asia.

With winds of up to 280kmh, Hurricane Katrina is comparable in strength to many of Australia's cyclones.

However, in terms of size and the damage it caused, Katrina makes our disasters look like a storm in a teacup.

Striking Louisiana, Mississippi and Alabama, Katrina was the biggest hurricane to hit the US since record-keeping began.

It led to the deaths of 1599 people and is estimated to have caused over 100 billion dollars in damage.

At its peak it measured around 640km in diameter. In comparison, Cyclone Tracy was only 50km wide.

However, despite such massive wind speeds and immense size, much of the damage was actually caused by storm surge.

A common feature of cyclones, storm surge is a sudden, dramatic rise in ocean levels caused by the increased winds.

In Katrina's case, the breaking of levees combined with a dramatic surge saw 80 percent of New Orleans flooded.

When the hurricane finally passed, lawlessness, disease and a slow relief effort quickly became the main problems.

So while it will be of little comfort to those sleeping out in the aftermath of Larry, they can at least console themselves that relief is on the way, no looting has been reported and health authorities insist the risk of disease is extremely low.


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