45th Anniversary of the Bhola Cyclone

ITOS I satellite picture of Bhola cyclone near peak intensity Nov. 12, 1970 (NOAA)

ITOS I satellite picture of Bhola cyclone near peak intensity Nov. 12, 1970 (NOAA)

On November 12, 1970, the deadliest tropical cyclone on record hit northeastern India and what was then East Pakistan.  The storm surge washed over many barrier islands and the flat shoreline of the Bay of Bengal killing approximately half of a million people.

Track of the Bhola Cyclone 1970 (Unisys)

Track of the Bhola Cyclone 1970 (Unisys)

The storm originated from a tropical depression that formed in the southern Bay of Bengal, in part from remnants of Tropical Storm Nora that had passed over the Malay Peninsula from the western Pacific.  The system was tracked via satellite by the Indian Meteorological Department (IMD).  The Dvorak Technique for estimating tropical cyclone strength from satellite presentations had only just been introduced and used in the United States.  Therefore the strength of the developing cyclone remained largely unknown.  The system drifted slowly northward for two days but by November 10th it began to accelerate and become more organized.

By Nov. 12th, the storm was moving rapidly toward the north-northeast and from ship reports the IMD was estimating the maximum sustained winds were near 130 mph (205 km/hr).  Relations between the Indian and Pakistani governments was hostile at the time and communication of weather data may have been affected.  But the Pakistani meteorological service did issue a warning for coastal residents; however few people responded by moving to reliable shelters.  Only a small number perceived the danger represented by the storm, but for others there were either no nearby shelters or means of reaching them.

That evening, the cyclone swept a storm surge of 35 feet (10.5 meters) ahead of it as it made landfall.  This washed over many of the flat, outlying islands including Bhola, the largest.  Whole fishing communities were obliterated.  The death toll could only be estimated roughly, since census records were non-existent. Somewhere between 300,000 and 500,000 people perished in the storm, making it the deadliest tropical cyclone on record.  The storm quickly dissipated once it had moved inland leaving an estimated US$86 million in damage.

But there were was more than material damage done by the cyclone.  Response to the massive disaster from the central government was slow in coming.  Offers of help from India were originally rebuffed by Karachi.  This exasperated long standing tensions between the peoples of West and East Pakistan and within a month an opposition party won elections in East Pakistan.  Friction between the the two factions led to violent outbreaks and retribution.  By March of 1971, East Pakistan declared itself the independent nation of Bangladesh and outright warfare began, broadening into the Indo-Pakistani War by December.  The conflict ended by Dec. 16, 1971, with Bangladesh being recognized as independent by the Pakistani government.  All of this sparked by a tropical cyclone and terrible human disaster.