According to the India Meteorological Department (IMD), Cyclone Dana is expected to reach the Odisha coast near Bhitarkanika National Park and Dhamra Port as a severe cyclonic storm (wind speed 89 to 117 kmph).
Cyclone Dana:
Emergence:
It is the third cyclone to form over the North Indian Ocean Region and the second to hit the Indian coast in 2024, after Cyclone Remal.
It is the first cyclone of the post-monsoon cyclonic season.
Naming of Cyclone Dana:
According to the World Meteorological Organization (WMO), Cyclone Dana was named by Qatar. “Dana” in Arabic means “generosity” and means “pearl of the most perfect shape, valuable and beautiful.”
Due to heavy rainfall:
Intense convection:
The western region is witnessing intense convection from this cyclone, extending up to the upper layers of the atmosphere.
Intense convection begins when warm, moist air rises, cools and circulates, causing moisture to condense into water droplets and form clouds.
As the rising air cools and condenses, it forms cumulonimbus clouds, which are typical for thunderstorms and provide favorable conditions for heavy rainfall.
Hot and humid air:
Hot, humid air flows into the center of the cyclone, causing more intense rainfall as convection increases.
The flow of warm, moist air helps maintain and intensify the cyclone and this strengthens the cyclone, resulting in intense rainfall over a relatively small area.
Madden Julian Oscillation (MJO) effect:
The MJO is conducive to convection leading to heavy rainfall.
MJO has two parts: High rainfall phase and low rainfall phase.
During the high rainfall phase, surface air circulation causes the air to rise and cause more rainfall. In the low-rainfall phase, air circulates at the top of the atmosphere, causing less precipitation than the downward deposition of air.
This dipole structure moves from west to east in the tropics, causing more clouds and precipitation in the high rainfall phase and more sunshine and drought in the low rainfall phase.
On the naming of cyclones:
The historical development:
The practice of naming storms after saints of the Roman Catholic calendar began in the Caribbean in the late 1800s.
The use of female suggestive names became common after World War II to draw more attention to hurricanes.
After criticism of gender bias, the naming system was updated in 1979 to include names based on both male and female, alternating between the two.
The beginning of the naming system:
The practice of naming cyclones in the North Indian Ocean region was started in the year 2000 by the World Meteorological Organization (WMO) which is a specialized agency of the United Nations.
Collaborative naming list:
A collaborative list of cyclone names was established by the Tropical Cyclone Regional Body (TCRB) in the North Indian Ocean.
TCRB is a group of 13 countries in the North Indian Ocean namely Bangladesh, India, Maldives, Myanmar, Pakistan, Sri Lanka, Oman, Thailand, Iran, Qatar, Saudi Arabia, United Arab Emirates and Yemen.
The process of making suggestions:
Each of the 13 member countries must submit 13 suggestions for names to the WMO panel, which reviews and finalises the names.
Global standardization:
The naming of cyclones makes their identification easier for both the media and the public, helping them to track cyclone progress and potential hazards.
Cycling of names and deleting them:
Names in the cyclone list are changed from time to time, thereby ensuring fresh selections over time.
Removed names (especially those associated with deadly or destructive hurricanes) are replaced with new suggestions to avoid negative associations.
Factors responsible for the formation of tropical cyclones:
Warm sea water:
Sea surface temperature of at least 27 ° C is required for tropical cyclone development. Warm water provides the heat and humidity needed to fuel the storm’s intense wind and convection process.
Coriolis force:
The coriolis effect, caused by the rotation of the earth, is necessary to accelerate a cyclone. This force weakens near the equator, so tropical cyclones usually form at least 5 ° north or south of the equator.
Low Wind Shear:
Vertical wind shear (difference in wind speed and direction at different altitudes) is important. High wind shear can disrupt a storm’s vertical structure, preventing it from strengthening.
Pre-existing Disturbances:
Tropical disturbances (such as low-pressure systems) can cause a cyclone to form around the air circulation.
Convection of air:
Clouds and storms form from the convergence of warm, humid air (which rises and cools) on the surface.
Effects of the cyclone:
The human impact:
Cyclones can cause massive loss of life due to strong winds, storm surges and floods. Thousands of people may be left homeless or displaced, leading to temporary or permanent loss of homes.
The loss of infrastructure:
Strong winds can cause power outages and structural damage, while flooding can disrupt transportation and communications.
The environmental impacts:
Strong winds and storm surges erode coastal areas, destroying natural habitats and structures along the coast.
Cyclones can cause long-term damage to forests, wetlands and marineecosystems, affecting biodiversity.
Agricultural losses:
Low-lying agricultural areas are vulnerable to seawater ingress and waterlogging from heavy rainfall, which can destroy crops and reduce agricultural productivity.
Prolonged rainfall can lead to water logging in fields, which can affect soil health and damage crops.
Four-phase Cyclone Warning System:
Pre-Cyclone Watch (Green):
It is issued 72 hours in advance. It gives warning about possible cyclonic movement and expected adverse weather in the coastal areas.
Cyclone Warning (Yellow):
It is issued at least 48 hours before the onset of adverse weather. It gives information about the location, intensity of the storm and advises on safety measures.
Cyclone Warning (Orange):
It is issued at least 24 hours before the onset of adverse weather. It provides detailed updates on cyclone conditions, expected landslides and associated impacts such as heavy rainfall and strong winds.
Post Landslide Forecast (Red):
It is issued at least 12 hours before the landfall. It provides detailed information on possible adverse weather conditions affecting inland areas after a landslide.
Necessary Measures for Effective Cyclone Disaster Preparedness and Mitigation:
Cyclone East:
Land use planning:
Land use and building codes should be enforced to restrict housing in sensitive areas.
Cyclone Early Warning System:
New impact-based cyclone warning system should be issued to inform about risks and preparatory actions with focus on local population and land use patterns.
The engineered structures:
Build structures designed to withstand cyclonic winds, including public infrastructure such as hospitals and communication towers.
Mangrove plantation:
To protect coastal areas from storm surges and erosion, community participation should be involved in these projects along with promoting mangrove plantation initiatives.
During the cyclone:
Cyclone Shelters:
Establish cyclone shelters in high-risk areas and ensure that the shelters are connected to major roads for quick evacuation and access during emergency situations.
Flood Management:
Seawalls, embankments and drainage systems should be adopted to control water flow and reduce flooding caused by storm surges and heavy rainfall.
After the storm:
Map of the risk areas:
Maps showing frequency and intensity of cyclones, including storm surges and flood risks, should be prepared based on historical data.
Revitalization of non-engineering structures:
To increase the resilience of non-engineered homes, communities should be educated on revitalization techniques (such as building steeply sloped roofs and stabilizing pillars).
Conclusion:
Cyclone Dana underscores the importance of proactive disaster management measures, including effective early warning systems, land use planning and community participation. By enhancing infrastructure resilience, implementing hazard mapping, and promoting mangrove conservation, we can better prepare for and mitigate the impacts of cyclones on vulnerable coastal areas.
