Meteorological Chronology
The remnants of Tropical Storm Nora from the Pacific, which had lasted for two days in the South China Sea, moved west over the Malay Peninsula on November 5. The remnants of this system contributed to the development of a new depression in the central Bay of Bengal on the morning of November 8. The depression intensified as it moved slowly northward, and the India Meteorological Department upgraded it to a cyclonic storm the next day. The storm became nearly stationary that evening near 14.5° N, 87° E, but began to accelerate to the north on November 10.
The hurricane intensified into a severe cyclonic storm on November 11 and began to turn towards the northeast as it approached the head of the bay. A clear eye formed in the storm, and it reached its peak later that day with sustained winds of 185 km/h (115 mph) and a central pressure of 966 hPa, equivalent to that of a Category 3 hurricane on the Saffir-Simpson Hurricane Scale. The cyclone made landfall on the East Pakistan coastline during the evening of November 12, around the same time as the local high tide. Once over land, the system began to weaken but was still considered a cyclonic storm on November 13 when it was about 100 km (62 mi) south-southeast of Agartala. The storm then rapidly weakened into a remnant area of low pressure over southern Assam that evening.
Read more about this topic: 1970 Bhola Cyclone