Top weather story of 2008: Cyclone Nargis
The top weather story of 2008 has to be the catastrophic impact of Cyclone Nargis on the nation of Myanmar (formerly Burma). Nargis (the Urdu word for 'daffodil') hit the low-lying, densely populated Irrawaddy Delta region of Myanmar on May 2, 2008. Nargis' Category 4 winds of 135 mph brought a storm surge of up to 4 meters (13 feet) to the coast, inundating regions up to 40 km inland. At least 140,000 people perished, according to official estimates by the U.N. and the government of Myanmar. This makes Nargis the ninth deadliest cyclone in world history. The storm made 800,000 people homeless, destroying 450,000 homes. Approximately 2.4 million people were significantly affected by the cyclone, and total damage has been estimated at $4 billion.
Recovery from the cyclone will take years. The loss of livestock, buffalo for plowing, fishing nets, and boats was near total in many regions of the coast. Fallen trees still block many transportation routes, and the much of the rich farmland used to grow crops has been made salty by the inland penetration of Nargis' storm surge. About 30% of the villages in the devastated region still have a high proportion of their homes using plastic or canvas sheeting for roofs or walls, and undernutrition and lack of clean water are still problematic. However, international aid has made a big difference, and much of the affected area has benefited from the aid.
A once-in-500-year event for Myanmar?
Tropical cyclones are uncommon in Myanmar, which has had only six Category 1 or stronger storms since 1970, and eleven since 1948. Nargis is the third strongest cyclone on record to hit Myanmar, and the deadliest and most damaging. The previous highest death toll from a tropical cyclone in Myanmar was 187, during the Category 1 storm that hit on May 7, 1975. Nargis is the first major tropical cyclone to hit Myanmar since Category 3 Cyclone Mala hit on April 28, 2006. Mala hit a less populated area less prone to storm surge, and killed 22 people and damaged 6000 buildings. It is remarkable that no other tropical cyclone over the past 300 years has hit the Irrawaddy Delta and caused major loss of life. An unusually strong and far-southward extending trough of low pressure turned Nargis to the east much farther south than is the norm for the North Indian Ocean. In the pre-1970 years, there is only one hurricane-force storm recorded to have hit Burma, a Category 1 cyclone in 1936 that killed 36 people. A significant cyclone hitting the Irrawaddy Delta causing thousands of deaths would very likely have been recorded, had this happened any time in the past 300 years. Such events were recorded in both India and Bangladesh during that period. Nargis appears to have been the only major tropical cyclone to hit the Irrawaddy River Delta in recorded history, and may be a once-in-500-year event.
Figure 1. Visible satellite image of Nargis shortly before landfall. Image credit:NASA.
Nargis' storm surge
Nargis took the worst possible path, tracking right along the low-lying, heavily populated Irrawaddy River Delta. Moreover, the storm hit at high tide, greatly increasing the impact of the storm surge. Tidal range in the Irrawaddy River Delta is about five feet between low tide and high tide, and the death toll would have been much, much lower had the storm hit at low tide. Further amplifying the storm surge's height was the fact that Nargis was moving rather slowly--about 11 mph. Slow moving tropical cyclones can drive a much higher storm surge into narrow estuaries that connect to the ocean, since there is more time for the surge to penetrate inland. Nargis' track, forward speed, and high tide timing created a "perfect storm" able to cause an unprecedented storm surge in the Irrawaddy River Delta. The only saving grace was the relatively small size of the cyclone.
Human factors helped make the storm surge worse. About 80% of the mangrove forest along Myanmar's coast has been destroyed, to make room for rice paddies and shrimp farms. Mangroves--tall, gnarly, salt-tolerant trees--act to blunt and slow down the progress of the storm surge and reduce the wave action of the ocean. Had more mangroves been left to survive, the impact of the storm surge would have been lessened. How much so, no one can say, for there are few observations of the storm surge to verify models of this. Keep in mind that the mangroves are far more effective in protecting against a sudden, powerful wave like the 2004 tsunami, compared to the slower, hours-long inundation of a storm surge.
Figure 2. Topography of Myanmar, with track of Cyclone Nargis superimposed. Image credit: NASA.
Failure of the Myanmar government
Nargis was remarkable not only for its death toll, but for the failure of Myanmar's dictatorship to provide adequate warnings before the storm. The Indian Meteorological Department (IMD), which is responsible for tropical cyclones warnings in the North Indian Ocean, classified Nargis as a "severe cyclonic storm" three days prior to landfall, and warned of landfall in Myanmar of Nargis as a Category 1 or 2 storm. However, the official state-controlled New Light of Myanmar newspaper carried this forecast the day before landfall: "the severe tropical cyclone NARGIS...is forecast to cross the coast during the next 36 hours...Under the influence of this storm, rain or thundershowers will be widespread...frequent squalls with rough seas will be experienced off and along the Myanmar coast. Surface wind speed in squalls may reach [50] mph." This forecast was buried on page 15 of the miscellaneous section of the newspaper. No mention of hurricane-force winds or of Nargis' storm surge was made. However, the IMD does not make forecasts of storm surge, which is something that needs to be corrected in the future, according to an excellent assessment of Cyclone Nargis published in Nature by Dr. Peter Webster of Georgia Tech. Dr. Webster also advocates that a relatively small investment by the developed world in improved warning systems and shelters for the region can dramatically lower death tolls and the money needed for aid responses for future storms. Sounds like a great investment to me!
Finally, Nargis was also remarkable for the initial refusal of Myanmar's government to allow foreign aid into the country after the storm. Over a week passed before significant aid was allowed in, which greatly exacerbated the suffering of the storm victims and undoubtedly led to a higher death toll.
Nargis links
Post-Nargis Joint Assessment (July 2008).
Post-Nargis Periodic Review I (December 2008).
Nature paper by Dr. Peter Webster of Georgia Tech (July 2008).
My next blog post will be Wednesday or Thursday, when I'll continue to report on the major weather and climate events of 2008.
Jeff Masters
Reader Comments
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Look, i'll trade you my cold Michigan air for your cold Florida air, okay???
Deal -- it was 83 here today. Can't even wear a suit without suffocating
sweet you can have my highs of 30
nice new avatar btw
Brownsville, TX~ Making gulf water drinkable too costly for now
Good stuff on the Atlantic Overturning Circulation. I had an ahh ha moment of my own not mentioned in either. It's finally cooled off around the gulf stream to create a gradient to get it going. In 2005 the monitering seemed to show it at it's slowest.. The waters around it were so hot then. Recently it's cooled around the gulf stream with the heat gathering more in Central Atlantic.
Surfmom~ Ponys here were pretty lively in that front too.
I hate the cold
It is great here in Port St Lucie FL
too late, i already traded with zoo... welcome to real cold, all you floridians!! Mwahahaha!!
Hopefully arctic air will not penetrate too deep south next week...
Anyone else notice a pocket of warmth off the coast of Delaware? It's almost warm enough to sustain a TC!!
LOW [1004 HPA] NEAR 17.0S 66.0E
Is likely to intensify further
Joint Typhoon Warning Center
Tropical Disturbance Summary (0300z 08JAN)
=========================================
An area of convection (Remnants of TC Billy/05S/03U) located at 15.1S 66.5E or 725 NM east-northeast of Runion. Recent animated water vapor and infrared satellite imagery shows deep convection flaring on the northeastern periphery of a broad low level circulation center evident in a partial 2126z AMSR-E Pass. The low level circulation center lies north of an upper level ridge axis in an area of moderate southeasterly vertical wind shear. However, the low level circulation center is also moving closer to the upper ridge axis, which may provide a reduction in shear values over the next 24 hours.
Maximum sustianed winds near the center is 20-25 knots with a minimum sea level pressure of 1007 MB. Because the low level circulation center is broad and upper level support is just beginning to improve, the potential for this disturbance to form into a significant tropical cyclcone within the next 24 hours is POOR.
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Tropical Cyclone Outlook
Region between 125E-142E
2:15 pm ACST January 8 2009
=============================================
A TROPICAL LOW [1002 hPa] is situated in the southeastern GULF OF CARPENTARIA near Mornington Island. At 11am it was near latitude 17S, longitude 139E, slow moving.
The LOW is expected to remain slow moving over water for the next few days, and may develop into a tropical cyclone later in the weekend.
Tropical Cyclone Formation Potential
===================================
Friday: LOW
Saturday: MODERATE
Sunday: HIGH
This is 97P on the NRL when it gets posted
Wait...that means it could be a hurricane (since it's symmetric warm-core)?
Comment Removed
Tropical Cyclone Warning Number ONE
ZONE PERTURBEE 05-20082009
10:00 AM Reunion January 8 2008
=====================================
At 6:00 AM UTC, Area of Disturbed Weather (1004 hPa) located at 13.0S 70.0E has 10 minute sustained winds of 20 knots with gusts of 30 knots. The disturbance is reported as nearly stationary.
Dvorak Intensity: T1.5
Near-Gale Force Winds
=====================
Squally weather exists within 250 NM radius from the center, extending up to 450 NM in the northern semi-circle.
Forecast and Intensity
====================
12 HRS: 15.3S 68.9E - 25 knots (Perturbation Tropicale)
24 HRS: 16.5S 67.5E - 30 knots (Depression Tropicale)
48 HRS: 17.7S 65.2E - 35 knots (Tempête Tropicale Moderée)
72 HRS: 19.7S 65.5E - 50 knots (Forte Tempête Tropicale)
Additional Information
=======================
Convection has intensified last night, associated with a new low located between the two lows monitored until yesterday (one near 10S and the other near 15S, Remnants of Billy) The system is expected to track southwestward due to the ridge in the southeast, then up to track, 0600z +48HRS, southward as the trough arrives in the southwest. The system is fed by a strong monsoon flow, and a favorable equatorwards outflow is present.
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corrected the stage of the system
Tropical Disturbance Summary (0830z 08JAN)
==========================================
An area of convection (98S) located at 13.4S 69.2E or 420 NM south-southwest of Diego Garcia. Based on multispectral satellite imagery, this area is a new developing low, seperate from the dissipated remnants of former tropical cyclone Billy which tracked westward and is located near 15.0S 66.0E. This position was moved 180 NM northeast of the previous position. Multispectral satellite imagery and a 0436z AMSU image indicates improved consolidation and convective banding wrapping into the low level circulation center with good inflow over the northeastern quadrant. A 0129z Quikscat image shows a somewhat elongated low level circulation cneter with many 20-25 knot unflagged winds and one 35 knot unflagged wind north of the center, associated with an intense area of deep convection. a 0000z ship report, 95 NM northeast, also indicate 33 knots with surface low pressure of 1004 MB. Upper level analysis indicates a generally favorable environment, although currently limited by moderate to high vertical wind shear with good radial outflow and warm sea surface temperatures and high ocean heat content. The low level circulation center is expected to track into lower vertical wind shera after 24 hours and should consolidate further
Maximum sustianed winds near the center is 20-25 knots with a minimum sea level pressure of 1003 MB. Based on the improved organization, formative banding and good radial outflow, the potential for this disturbance to form into a significant tropical cyclone within the next 24 hours is UPGRADED TO FAIR.
Tropical Disturbance Summary
TROPICAL DEPRESSION FOUR-F
18:00 PM FST January 8 2009
===================================
At 6:00 AM UTC, Tropical Depression 04F (998 hPa) located at 20.0S 174.0E reported moving southeast at 15 knots. Position FAIR based on multispectral infrared/visible imagery with animation, peripheral surface observations, and latest Quikscat Pass. Sea surface temperature is around 31C.
Organization in the last 24 hours has not improved markedly with deep convection sheared to the east of low level circulation center. TD FOUR lies in a sheared environment with 20-30 knot winds at 250 hPa. An active convergence zone lies to the north of the system with 20 knot at the surface. A southeasterly surge remains to the south.
Development remains unfavorable as TD FOUR gets caught up by a fast moving upper trough from the west which will maintain a sheared environment. TD FOUR is expected to develop as a hybrid system.
Global models (US/UK/EC) has picked up the system and moves it fairly rapidly southeast with little intensification.
POTENTIAL FOR THE SYSTEM TO DEVELOP INTO A TROPICAL CYCLONE WITHIN THE NEXT 24 HOURS REMAINS LOW.
Wow! Billy's remnants are still spinning? It looks like it has potental for regeneration...
http://www.spiegel.de/international/germany/0,1518,599784,00.html
The front came through here around 2:30 a. m. with a short burst of heavy rainfall. Definitely it's cooler this morning; yesterday at this time it was almost 10 degrees warmer. . .
Starting to warm up a little here though, which is nice.
(I mean, from -7 area to around freezing.)
Still remaining very cold at night, sharp drop each night to silly temperatures.
Hurricane Tebow is about to come ashore at 8 p.m. in Miami tonight. It is advised the people evacuate Sooners rather than later.
Hoping it warms up in Europe - spouse has a business trip planned for February. These temps. and weather will make my Florida man suffer.... hoping it warms by then.
Cot., the only thing this cold weather is good for (IMHO) is snuggling up with the furry four-leggeds.... it's 52 degrees this morning here in SWFL -- I know there are waves to surf w/thanks to the cold front and I could snitch out for a quick hour session before work..... but the cold... -- I feel like the dog... I really want to go out...but as soon as the temp hits my face...I run back in the house.
The Moon Glow was lovely last night -- let's hope my herd didn't get into too much mischief.
Atmoaggie/Post 279- Question regarding the Japanese Global Resolving Model that figures in/resolves MJO --- will we have that for a reference during this year's Hurricane season?
There is no cheese for my whine this morning (brrrrr) -- got to suck it up... have an hour & change to ride a wave -enough talk and tapping of keys JUST GOT TO DO IT! Adios
Tropical Cyclone Formation Alert (1500z 08JAN)
=========================================
An area of convection (98S) located at 14.0S 70.2E or 420 NM south-southwest of Diego Garcia. Animated infrared satellite imagery and a 1226z SSMIS image continues to depict a rapidly consolidating low level circulation center with a defined low level circulation center and multiple bands of deep convection wrapping into the center. Previous ship reports a scatterometer data supporting 25-30 knot system with a surface low pressure of 1002 MB. Upper level analysis indicates a generally favorable environment, although currently hindered by moderate to high vertical wind shear, with good radial outflow and warm sea surface temperature and high ocean heat content. The low level circulation center is expected to track into lower vertical wind shear within 12-24 hours and should also tap into the midlatitude westerly flow to its south, resulting in improved poleward outflow which will allow the system to strengthen to 35 knots.
Maximum sustained winds near the center is 25-30 knots with a minimum sea level pressure of 1002 MB. Based on the improved organization, tight banding, good radial outflow, and expected track into an improved environment, the potential for this disturbance to form into a significant tropical cyclone within the next 24 hours is UPGRADED TO GOOD.
Tropical Cyclone Warning Number TWO
PERTURBATION TROPICALE 05-20082009
16:00 PM Reunion January 8 2008
=====================================
At 12:00 PM UTC, Tropical Disturbance (1002 hPa) located at 14.0S 70.7E has 10 minute sustained winds of 25 knots with gusts of 35 knots. The disturbance is reported as moving south at 6 knots.
Dvorak Intensity: T2.0
Forecast and Intensity
====================
12 HRS: 14.0S 70.7E - 25 knots (Perturbation Tropicale)
24 HRS: 15.0S 69.1E - 30 knots (Depression Tropicale)
48 HRS: 15.9S 67.0E - 40 knots (Tempête Tropicale Moderée)
72 HRS: 17.2S 66.3E - 55 knots (Forte Tempête Tropicale)
Additional Information
=======================
Convection built last night remains active today, fed by a good monsoonal flow and a favorable upper level equatorward outflow. The system is expected to track southwest due to the low level ridge in the southeast, then southward as the trough arrive in the southwest. The system should go on intensifying with the setting up to (24HRS) of a new upper level outflow due to the polar westerly jet.
Viewing: 301 - 340
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