Over the past few days, relentless rainfall and turbulent weather conditions have disrupted daily life across several eastern and northern states of India. Amidst this atmospheric instability, a specific name has captured public attention across social media networks and digital news platforms: 'Cyclone Arnab'. While thousands of online users actively shared precautionary warnings and updates under this designation, professional meteorologists remained clear about the scientific reality of the system. The India Meteorological Department (IMD) never officially classified this weather disturbance as a cyclonic storm. Instead, it was designated as a deep depression—a robust low-pressure system that originated in the Bay of Bengal and moved inland, triggering widespread rainfall but failing to meet the strict scientific parameters required to be designated as an official cyclone. This discrepancy raises essential questions: if the system was never a cyclone, why did the name Arnab spread so rapidly, where did the name originate, and how does the global system of naming these storms actually function?
Understanding the Meteorological Thresholds: Depression vs. Cyclone
To understand why this system did not earn the title of an official cyclone, one must look at the specific classification criteria used in meteorology, which are based on wind speeds and isobaric patterns. Atmospheric disturbances begin as simple low-pressure areas, which can gradually intensify into a depression. A depression is characterized by sustained wind speeds at the surface ranging between 31 and 50 kilometers per hour, equivalent to 17 to 27 knots, and features two closed isobaric contours. If the system continues to gather energy, it upgrades to a deep depression. At this stage, the sustained wind speeds increase, ranging from 52 to 61 kilometers per hour, which translates to 28 to 33 knots, and the system displays three closed isobaric contours.
For a deep depression to be officially upgraded to a cyclonic storm, the sustained wind speed averaged over a three-minute interval must reach or exceed 63 kilometers per hour, or 34 knots. Additionally, such a system must be supported by four or more closed isobaric contours. In the case of the recent weather system, the maximum sustained winds remained capped between 55 and 65 kilometers per hour, preventing it from consistently crossing the scientific threshold of a cyclonic storm. Because the system was hovering right on the edge of intensification, social media users, anticipating the next name on the regional list, prematurely labeled the system as 'Cyclone Arnab' before the IMD could make an official determination.
The Origin and Meaning of the Name Arnab
Many people have wondered whether 'Arnab' is an acronym or if it has a specific full form. It is important to clarify that Arnab is not an abbreviation of any kind and does not carry a full form. It is a proper noun of Bengali origin, officially contributed to the regional storm-naming pool by Bangladesh. In the Bengali language, the word Arnab translates directly to "ocean" or "sea." According to the official list maintained by the World Meteorological Organization (WMO), the standard pronunciation for this name is indicated as 'Ornab.' Therefore, the name has no direct connection to any specific individual; rather, it is a traditional term reflecting the vastness of the ocean.
How the Regional Naming Matrix Works
The system of assigning names to tropical storms is highly structured and governed by strict international protocols established to ensure effective communication during disasters. The WMO, a specialized agency of the United Nations established in 1950, coordinates global meteorological standards from its headquarters in Geneva, Switzerland. For storms developing in the North Indian Ocean region, which encompasses both the Arabian Sea and the Bay of Bengal, names are decided by a dedicated body known as the WMO/ESCAP panel. ESCAP stands for the United Nations Economic and Social Commission for Asia and the Pacific.
This regional panel comprises 13 member nations: India, Bangladesh, Pakistan, Sri Lanka, Maldives, Myanmar, Thailand, Oman, Iran, Saudi Arabia, the United Arab Emirates, Qatar, and Yemen. Under the agreed framework, each of these 13 countries submits a list of 13 unique names, resulting in a master database of 169 names. These names are arranged in a pre-determined sequential matrix and are used one after the other as new storms develop. Since Bangladesh's contribution, 'Arnab' (Ornab), was the next name scheduled on the active list, the public began using it as soon as the deep depression formed in the Bay of Bengal. Whenever the next official cyclonic storm develops in this region, it will be assigned a name submitted by India.
Why Devastating Names are Retired
An important rule within the international storm-naming protocol is the permanent retirement of names associated with extreme devastation and loss of life. Historically, names of highly destructive cyclones such as Titli, Fani, and Amphan have been completely removed from the rotation list after they caused severe impact. This is done to prevent confusion in historical records and out of sensitivity toward the affected populations. The master list essentially functions as a pre-planned registry of names, allowing disaster management authorities across different countries to issue clear, unambiguous warnings and coordinate relief operations efficiently without confusion.
Why Unnamed Weather Systems Pose a Severe Threat
A common misconception among the general public is that a weather system is only dangerous if it carries an official cyclone name. Meteorologists caution that this assumption can lead to dangerous complacency. Even when a system fails to reach the wind speed criteria of a cyclonic storm, a deep depression carries immense amounts of atmospheric moisture and energy. Such systems are fully capable of triggering torrential downpours, severe urban waterlogging, swelling river basins, and destructive landslides in mountainous terrains.
This particular deep depression has demonstrated significant power despite lacking an official name. The system made its initial landfall on the night of September 23-24 near Kalingapatnam in Andhra Pradesh. As it moved further inland, carrying vast amounts of moisture, it brought continuous heavy rainfall over the next 72 hours across Odisha, Andhra Pradesh, Chhattisgarh, Uttar Pradesh, and Bihar. Consequently, the severity of a weather event should never be judged solely by its official title, but rather by the specific wind advisories, precipitation forecasts, and safety directives issued by local administrations.
