CYCLONE "NARGIS" OF MAY 2-3, 2008 IN MYANMAR (BURMA)

Preliminary Report
George Pararas-Carayannis

Introduction

Cyclone NARGIS was one of the deadliest and most destructive tropical cyclones to ever hit Myanmar (formerly Burma). The cyclone was responsible for unprecedented loss of life and destruction. It was particularly devastating in the low-lying and densely populated Ayeyarwady (Irrawaddy) River delta region of Myanmar. The following is a preliminary report.

Formation and Path of Cyclone NARGIS

April 28, 2008: In the early morning hours of April 28, the cyclonic storm system named NARGIS begun forming over the southwest and adjoining southeast & westcentral Bay of Bengal. As of 21:00 PM UTC the storm was centered near 13.0N, 85.5E.near lat. In the afternoon NARGIS intensified into a severe cyclonic storm. The system moved initially in a northwesterly direction but then recurved and moved slowly in a northeastward direction and, for a while, remained almost stationary in the Bay of Bengal at about 1210 km off Cox’s Bazar coast, 1280 km away from Chittagong, 1200 km away from Mongla, and about 550 kms east of Chennai, India. At that time the storm system was centered at about 14.50 N and Long 86.50 E, about 950 km west-southwest of Sandoway (Myanmar).

April 29, 2008: In the morning of April 29, 2008, NARGIS further intensified. It was then classified as a tropical depression that was quickly turning into a very severe cyclonic storm system - with the potential to strike either Bangladesh or Myanmar within four or five days. At the time NARGIS was over 1,100km away from the Bangladesh coast. The wind speed within 54 kilometers of the storm center was about 62 kmph, with gusts expected to rise up to 88 kmph. NARGIS was closely watched, as it was the first cyclonic storm in the Bay of Bengal since Cyclone SIDR had struck Bangladesh in November of 2007 with wind speeds of 210kmph. SIDR had killed more than 3,000 people in Bangladesh and had also caused damage to huge assets and crops.

Tracks of Cyclones in the Bay of Bengal (India Met Office)

Since there is a tendency for most storm systems to move in a northerly direction in the Bay of Bengal, there was concern that NARGIS could intensify further and move in a northerly direction towards Bangladesh or the Indian coast. There was also concern that NARGIS could change direction, move in a northeast direction and possibly hit the Myanmar coast.

April 30, 2008 - By April 30th, NARGIS remained practically stationary in the west central and adjoining east of the central Bay of Bengal, and was now laying near 15.0N 87.5E, or 850 kms west-southwest of Sandoway (Myanmar), but moving north very slowly. At 18:00 PM UTC, Nargis was upgraded as a Very Severe Cyclonic Storm NARGIS (980 hPa). Gathering strength, its minimum sustained wind speed ranged between 90kmph and 120kmph within the 54km radius of its center. Maximum 3 minute sustained winds near the center were 65 knots with an estimated central pressure of 980 hPa. Satellite imagery showed broken to solid intense to very intense convective clouds between 13.5N to 19.0N and 85.5E to 89.5E in association with the system. It was still unknown where it was going to make landfall. Already, the Met Office in Dhaka (Bangladesh) had declared NARGIS as a severe cyclonic storm - since its wind speed had exceeded the 89kmph threshold. There were expectations that the wind speed could exceed 120kmph, in which case the storm would have been categorized as “very severe”. However, such winds speeds had not reached that level yet.

May 1, 2008: NARGIS was still almost stationary on the West Central Bay of Bengal but intensified further while moving very slowly towards the North Eastern Bay of Bengal. At the time, the eye of the storm system was about 1,000 kilometers (km) southwest of Chittagong port, 935km southwest of Cox’s Bazar port, and 875km south-southwest of Mongla port.

Cyclone Nargis Path over the Irrawaddy River Delta Region (web graphic)

May 2, 2008: A special bulletin of the Met Office in Dhaka, stated that the eye of the tropical storm was about 1,000 kilometers (km) southwest of Chittagong port, 935km southwest of Cox’s Bazar port, and 875km south-southwest of Mongla port, with a minimum wind speed between 90 and 120 kilometers per hour (kmph), within a 54km radius of its center. By the evening hours of May 2nd, NARGIS changed its course eastward and started to cross the Myanmar coast. At this time the storm system was centered about 210km west of Haing Gyi Island at the mouth of the Irrawaddy River and about 430km southwest of Yangon. At about that time, Haing Gyi Island begun being inundated by a storm surge that reached 3 to 3.5 meter (10-12 feet). NARGIS gained further strength and begun exhibiting an erratic behavior as it started to cross the Irawaddy river delta coast at about 6:00pm (local time) on Friday, May 2. At 2030 hrs (IST - Indian Standard Time) NARGIS was over Myanmar near lat. 16.0º N long. 95.0ºE about 160 km Southwest of Yangon.

The Winds at Landfall

When it made direct landfall on Maynmar, NARGIS was an upper category 3, bordering on category 4, storm system with winds of 130 -135 mph. Throughout Friday night (May 2) and Saturday morning (May 3) it continued battering the Irrawaddy delta with winds of up to 150 mile (240 km/h) an hour and during that time interval it dumped 20 inches of rain. Traveling over land the winds eventually diminished in strength. When it struck the capital city of Rangoon (Yangon), NARGIS had diminished to a Category 1 storm, with maximum winds of 80 mph. At 5:30am local time on Saturday, May 3, the winds at the Yangon airport were clocked at 69 mph, but with gusts of up to 138 mph., at which time the measuring anemometer there failed. More than likely, greater gusts were experienced in the airport area and elsewhere near Rangoon.

The Cyclone Surge

Maximum reported flooding by the cyclone’s surge was at least 4 meters (13 feet), but probably greater in certain areas of the Irrawaddy Delta region. The destructiveness of the surge resulted form NARGIS's azimuthal direction of approach from the east to the southern tip of the peninsula fronting the delta region - which resulted in maximum winds having a counterclockwise circulation in the shallow offshore continental shelf area. These counterclockwise winds and the coastal geomorphology of the region contributed to a water pile-up effect and the resulting high storm surge into the bay that flooded the coastal and low-lying inland areas. Had NARGIS made landfall further north or made a crossing further south of this region, the surge and the destruction would have been much less. Also, the change in the azimuthal path near the river delta region from near east to a northeast direction contributed to the water pile up effect and the resulting high surge.


Death Toll and Damages

The city of Rangoon and five central and southern states, Yangon, Ayeyawaddy, Bago, Mon and Karen were the most severely affected regions of Myanmar and declared as disaster areas. There was extensive flooding and destruction of boats, homes and structures. All utilities were down. The destruction was particularly extensive because most structures in this region are poorly built. Worse hit was the densely populated Irrawaddy River delta region. This is a low-lying coastal region, which is highly vulnerable to storm surges. Reportedly, entire villages disappeared. Some 95% of the homes in the city of Bogalay in the Irrawaddy delta were destroyed and most of its 190,000 residents were rendered homeless. Almost all of the deaths in the Irrawaddy river delta region, were from drowning due to the high storm surge. As of Tuesday May 6, 2008, the official total death toll in Myanmar was greater than 22,000, with thousands more people missing. At least 10,000 people were reported killed in the township of Bogalay alone. The final death toll is expected to be much greater than what has been reported so far - perhaps as many as 100,000 people may have been killed. Cyclone Nargis has been the deadliest natural disaster to hit Myanmar in recent history.

Two NASA satellite photos show the devastating effect of Cyclone Nargis over the Irrawaddy delta region of Myanmar. The image on the left taken in April 15, 2008 shows the Irrawaddy River flowing south and splitting into numerous tributaries. Rivers and lakes are sharply defined against a backdrop of vegetation and agricultural land. The image on the right was taken on May 5, 2008 and shows the entire coastal plain being flooded after Cyclone Nargis direct hit. The city of Yangon (located by the red rectangle) was almost completely surrounded by floods.

Cyclones and Cyclone Surges in Myanmar

Although not frequently, cyclones and their surges have struck Myanmar in the past. However, none of the past historic cyclones was as severe as NARGIS in terms of destruction. The most recent event was the powerful Cyclone MALA which, on April 28, 2006, swept ashore over Myanmar with winds near 210 kilometers per hour (130 miles per hour). The storm inundated the country with heavy rain and left widespread flooding in its wake. According to the Myanmar state media, one person died and 21 others were injured by this storm.

Another recent event, Cyclone GWA of May 4, 1982, was a Category 4 storm system with winds up to 140 mph winds. However, GWA made landfall on an area further north of NARGIS. Although, GWA's surge was as high - at about 4 meters - it was confined and had a far lesser destructive impact. GWA's winds were unable to pile up as much volume of water along the southern shore of the Irrawaddy River Delta. Reportedly only five people lost their lives to GWA – although a much higher number is suspected.

Another tropical cyclone that struck Myanmar on May 7, 1975 was a Category 1 storm system. No details are available, but according to sketchy reports, 187 people were killed. According to a United Nations database, another windstorm (probably a cyclone) killed about 2,700 people in 1926.

No Warning Issued

Constant watch is kept on the Bay of Bengal for the generation of tropical cyclones with the help of satellite imagery, particularly that of the Indian geostationary satellite, INSAT. Also, the likely movement of storms is normally predicted for this region with the help of track prediction models and by reference to past climatology, based on125 years of cyclone data. As early as April 29, 2008, and with the help of such technology, NARGIS had been readily identified as a tropical depression that was turning into a dangerous cyclonic storm system, which had the potential to strike either Bangladesh or Myanmar within four or five days. However, the storm was practically stationary and its path could not be easily predicted. Although NARGIS was still over 1,100km away from the Bangladesh coast, precautions were taken in that country and shelters were activated. However, no similar precautions or warnings were reported from Myanmar. Even if there was a warning, there was no safe place in the Irrawaddy river delta region, to evacuate the hundreds of thousands of residents of the region.

 

Preliminary Assessment of NARGIS's Erratic Formation and Path.

According to meteorological reports (from India and Bangladesh), up to the 25th of April 2008, there was a persistent upper air cyclonic circulation over the South Andaman Sea and the Southeast Bay of Bengal which - on the 26th of April - contributed to the formation of a low pressure area in the southeast region of the Bay of Bengal. At 0830 IST (Indian Standard Time) on April 27, a depression was identified over the southeast Bay of Bengal, with center around 12.00 N and 87.00 E - about 750 km east-southeast of Chennai, India. The depression begun moving very slowly in a northwestward direction. At 1730 IST of the 27th of April, the system intensified into a deep depression - centered now near 12.00 N and 86.50 E, about 700 km east-southeast of Chennai. High sea water temperature, low vertical wind shear, upper level poleward outflow and an increasing convergence in the lower levels, contibuted to the formation of a deeper depression, which became further intensified into a "Cyclonic Storm" and given the name “NARGIS”.

At 0530 hours (IST) of April 28, this cyclonic storm was practically stationary. At that time its center was at 13.00 N and 85.50 E, about 550 km east of Chennai. However, by 1430 IST of the same day, NARGIS further intensified into a "Severe Cyclonic Storm". Upper anticyclonic circulation to the southeast of NARGIS, forced it to move slightly in a northward direction and contibuted to its increased intensity into a "Very Severe Cyclonic Storm". At 0830 (IST) of April 29, NARGIS was centered near 13.50 N and 85.50 E, about 550 km east-northeast of Chennai. The system then moved northeastwards.

At 0830 ( IST) of April 30, NARGIS was centered at 14.50 N. 86.50 E, about 950 km west-southwest of Sandoway (Myanmar). NARGIS' directivity to an eastward path was probably caused by the upper air cyclonic circulation in the lower tropospheric levels over the Sub-Himalayan West Bengal & Sikkim area - which had persisted on April 25 and 26, and had begun moving eastwards on April 27.

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