The 2008 North Indian cyclone season was one of the most destructive tropical cyclone seasons in modern history, causing more than 140,000 fatalities and over US$15 billion in damage. At the time, it was the costliest season in the North Indian Ocean, until it was surpassed by 2020. The North Indian Ocean cyclone season has no official bounds but cyclones tend to form between April and December. These dates conventionally delimit the period of each year when most tropical cyclones form in the northern Indian Ocean. There are two main seas in the North Indian Ocean—the Bay of Bengal, which is east of India, and the Arabian Sea, which is west of India. The official Regional Specialized Meteorological Centre in this basin is the India Meteorological Department (IMD), however the Joint Typhoon Warning Center releases unofficial advisories for military interests. An average of four to six storms form in the North Indian Ocean every season. Cyclones occurring between the meridians 45°E and 100°E are included in the season by the IMD.

During 2008, the IMD monitored a total of ten depressions across the North Indian Ocean, significantly below the average of fifteen. Of these systems, seven developed into deep depressions, four into cyclonic storms, and one into a very severe cyclonic storm. The JTWC unofficially tracked seven systems, with six having one-minute sustained winds greater than , slightly above their 32-year average of five. Activity was mainly confined to the Bay of Bengal, with only two depressions developing in the Arabian Sea. Collectively, there were a total of 30 days of activity in the basin, with no storms existing simultaneously.

The first and most destructive storm of the season, Cyclone Nargis struck the Irrawaddy Delta in southern Myanmar, with a storm surge. Approximately 800,000 homes were severely damaged or destroyed and infrastructure was devastated. An estimated 138,373 people lost their lives and damage reached K13 trillion (US$15.6 billion). Nargis is regarded as the worst disaster in the nation's history as well as the fourth-deadliest tropical cyclone on record. Other storms throughout the season caused significant damage in Bangladesh, India, Sri Lanka, and Yemen. A depression in October was responsible for 180 deaths and US$1.638 billion in damage across Yemen. Overall, approximately 138,927 people were killed and losses totaled $15.4 billion (2008 USD). __TOC__

Season summary

Systems Extremely Severe Cyclonic Storm Nargis

In late April, the Intertropical Convergence Zone became very active over the Bay of Bengal and later spawned a low-pressure area on April 26. Being in an environment with low wind shear, favorable outflow, and high sea surface temperatures, the system would consolidate into a depression the following day. Tracking slowly westward, the depression intensified, becoming Cyclonic Storm Nargis on April 28. That day, steering currents weakened, causing the system to become nearly stationary before a trough caused it to move northeasterly, and later easterly. Hours before striking southern Myanmar on May 2, Nargis would attain its peak intensity with winds of and an estimated central pressure of 962 mbar (hPa; ). The JTWC estimated the system to be stronger, attaining one-minute sustained winds of . Once inland, the system gradually weakened and dissipated early on May 4.

Striking the Irrawaddy Delta with unprecedented intensity, Nargis produced a devastating storm surge over the region and a maximum wind speed of 190 km/h was also reported. Approximately of land was inundated by the storm, affecting roughly 11 million people, 2.4 million severely. Infrastructural impacts were tremendous, with 450,000 homes, 4,000 schools, and 75 percent of healthcare facilities destroyed and 350,000 homes severely damaged. With approximately 140,000 fatalities taking place in Myanmar, Nargis is regarded as the worst disaster in the country's history and ranks as the fourth-deadliest tropical cyclone on record. Damage from the storm amounted to K13 trillion (US$15.3 billion), the majority of which occurred within the private sector.

In the immediate aftermath of the cyclone, numerous members of the international community were prepared to provide Myanmar with aid. For several weeks, the State Peace and Development Council (Myanmar's military junta) insisted that the nation could cope with the disaster and refused aid. This was soon determined to be ignorance of the situation and put millions of lives at risk. Some reports indicated that the army even obstructed private relief, setting up check-points, confiscating goods, and arresting those trying to help. In 2009, it was stated that the actions of the government could be condemned as crimes against humanity for "intentionally causing great suffering, or serious injury to body or to mental or physical health."

Depression ARB 01

In early July, the seasonal monsoon over the Arabian Sea strengthened; a trough developing around the same time off the coast of Karnataka increased the local pressure gradient. The interaction of these two systems led to the formation of a low over the southern Arabian Sea on June 4. Situated in a region of low to moderate wind shear, upper-level divergence, and convergence, the low consolidated into a depression the following day while situated roughly southwest of Mumbai, India. Little intensification occurred over the following day as it moved north-northwestward; the depression attained peak winds of and a pressure of 994 mbar (hPa; ). Late on June 6 and into the early hours of June 7, interaction with land caused significant weakening, with the system degrading to a remnant low that morning. The remnants of the depression continued westward and brought locally heavy rains to parts of Oman.

Depression BOB 02

Early on June 15, an area of low pressure formed within the monsoonal trough over the northern part of the Bay of Bengal. Over the next 24 hours deep convection developed around the low-pressure area and thus it was upgraded to Depression BOB 02 early the next day, as it was located about , southeast of Kolkata, near to the Bangladesh coastline. However it as the depression was located within an area of moderate to high vertical wind shear, it did not develop further. Later that morning before the depression made landfall it reached its peak intensity with a central pressure of 988 hPa/mbar. The depression then made landfall on the Bangladesh coast and slowly weakened into an area of low pressure, whilst located over Jharkhand in India.

Torrential rains associated with the depression fell across much of Assam, Orissa, West Bengal, and Jharkhand. A maximum of of rain fell in Kalaikunda Air Force Station in West Bengal in 48 hours between 17 and 18 June of which 530 mm fell on 18 June. Additional rains spread into Himachal, Uttarakhand, and Arunachal pradeshes. In Assam, the Brahmaputra River overtopped its banks and flooded 350 villages, affecting roughly 400,000 people. At least 23 people lost their lives in the region. In nearby Arunachal, a series of landslides near Itanagar killed 19 people and injured 15 others. Flooding around Midnapore, West Bengal, killed at least nine people while 21,000 others were affected. Across northeast India, approximately 8 million people were affected by the floods, of which 2 million were rendered homeless. At least 56 people lost their lives, 31 of which occurred West Bengal.

Depression BOB 03

On August 9, a tropical depression formed in the North Indian Ocean, south of Orissa, India. Early the next day, the depression made landfall on the Orissa coast. The IMD did not upgrade it until it was overland near Puri. Consequently, it was designated as a land depression in the end of monsoon season report. Later in the day, the IMD issued its final advisory on the depression as it weakened into a low-pressure area. Madanpur Rampur in Orissa received 220 mm of rainfall on 9 August.

Monsoonal rainfall associated with the depression triggered extensive flooding in Andhra Pradesh. Flash flooding occurred on many rivers throughout the state. At least 61 people were killed across the state and 40,000 were displaced from their homes. At 3,000 homes were flooded.

Deep Depression BOB 04

On September 14 an area of low pressure formed southeast of Kolkata, India. During September 15 the IMD designated this area of low pressure as Depression BOB 04. Later that day the JTWC issued a Tropical Cyclone Formation Alert on the tropical depression. During the morning of September 15 the depression intensified into a Deep Depression as it moved closer to the Orissa Coast near Chandbali on 16 September and maximum surface wind of was reported by Chandbali at 1700 UTC of 16 September. Later that day the JTWC issued their first advisory on this system designating it as Tropical Cyclone 02B The Depression then made landfall on the Orissa coast later that day. So the JTWC issued their last advisory on the depression later that day. However the IMD kept issuing advisories on the Deep Depression. The RSMC then downgraded it to a depression on September 18 as it moved further inland. The RSMC issued their final advisory the next day as the depression had weakened into a well marked low-pressure area. The track of Deep Depression making inland into Uttar Pradesh after crossing Orissa

Baliguda in Orissa received 430 mm of rainfall in 48 hours between 17 and 18 September. The Deep Depression caused 10 deaths in the state of Orissa. The Depression also caused 15 deaths in Uttar Pradesh, its state capital Lucknow received the heaviest rains for September in the last 10 years. Over 100 fishermen were reported missing as 25 trawlers capsized in the Bay of Bengal off Bangladesh's southern coastal areas as the sea turned rough due to a depression. The Deep Depression also caused storm surge up to 15 to 20 feet high.

Overall, the storm killed at least 25 people in India (10 in Orissa, 15 in Uttar Pradesh), but overall damage was minor.

Deep Depression ARB 02

On October 19 the IMD noted that an area of low pressure which located to the south east of Salalah, Oman had intensified into a tropical depression and was assigned the number ARB 02. On October 21 IMD updated the system to a Deep Depression while it lay 700 km south of Salalah, Oman near the east coast of Somalia. It lost its strength while crossing the Gulf of Aden due to entry of dry air and land interaction as it passed close to the northeastern coast of Somalia. It later was downgraded to a Depression, named TC 03B by the JTWC.

On October 24 it made landfall on the south-eastern coast of Yemen, leaving at least 26 civilians and six soldiers dead while trapping hundreds of people due to flooding and torrential rainfalls. The latest figure of casualties is of 180 persons dead and 100 others missing, mostly from the region of Hadhramawt, where the storm made landfall. 733 houses were destroyed in the governorates of Hadhramawt and Al-Mahrah, while 22,000 people were displaced. The Yemeni Government declared the two aforementioned governorates as disaster zones. The most affected areas map released by ReliefWeb.

Overall, this weak storm killed at least 180 people in Yemen. Damage is estimated at $1.638 billion (US$).

Cyclonic Storm Rashmi