IMD has said that a low-pressure area has also formed in the Arabian Sea, which is moving northeast toward Dwarka and the Gujarat coast. Additionally, a western disturbance is active over northern India.”

“The well-marked low-pressure area over the Bay of Bengal is now turning into a cyclonic storm as its speed is gradually increasing, and it is rapidly moving towards the north-northwest coast. The Meteorological Department has also stated that as soon as the speed of the low-pressure system exceeds 63 KM per hour, it will turn into a cyclone. Dr. Anand Kumar Das, a scientist from the India Meteorological Department (IMD), said in a conversation with Hindustan that by noon, its speed had been recorded at 55 KM per hour.”

“In its latest bulletin, IMD has said that the deep depression will cross the coasts of Odisha and adjoining Andhra Pradesh by tonight, Thursday (October 2). During this period, strong winds with a speed of 75 kilometers per hour may occur. The Meteorological Department has also stated that the cyclonic circulation will weaken by the next day, i.e., October 3, and the wind speed will decrease to 45 to 55 kilometers per hour, but its impact will continue for a few days.”

IMD has said that due to this weather event, more than half a dozen states may experience rain accompanied by strong winds over the next 5 days. According to the Meteorological Department, Odisha, West Bengal, Andhra Pradesh, Jharkhand, Chhattisgarh, Bihar, parts of eastern Madhya Pradesh, and eastern Uttar Pradesh could experience heavy rain with intense thunder and strong winds.Heavy Rain in Odisha
Meanwhile, rain was also recorded in Odisha on Thursday morning. According to IMD, heavy rainfall has occurred in Odisha. The state government has deployed personnel and machinery in the identified sensitive districts to deal with the situation. An official said that all parts of the state, mainly the coastal and southern regions, have been experiencing heavy rain since Wednesday. IMD has issued a heavy rainfall warning for all 30 districts of the state today.

The storm will cross Odisha at night. IMD has stated that this storm is likely to cross Odisha by the night of October 2 and reach the coasts of Gopalpur and Paradip, adjoining Andhra Pradesh. According to weather experts, a deep depression is a condition that comes after a well-defined low-pressure area and before a cyclonic storm, usually followed by heavy rain and strong winds. IMD has advised fishermen not to venture into the sea near the Odisha coast until October 3.”Here is the list of some of the oldest roads in the world that still exist:Road to Giza (Egypt): Dating back to 2600 BC, used for transporting stones to the Pyramids of Giza.The Ridgeway (UK): Used for over 5000 years, is part of the Icknield Way trail.King’s Highway (Middle East): An 8th-century BC trade route crossing Sinai towards the Mediterranean.Grand Trunk Road (South Asia): In use since at least the 4th century BC, connecting Bangladesh, India, Pakistan, and Afghanistan.Via Appia (Italy): Built in 312 BC, parts remain paved and are walkable.Silk Road (Asia): Network of trade routes originating around 200 BC with surviving sections visible.Persian Royal Road (Iran and Turkey): 5th century BC road connecting Sardis and Susa.Via Augusta (Spain): Roman road with visible milestones and parts still existing.Watling Street (England): An Iron Age and Roman road now underlying modern routes.Nakasendo Highway (Japan): Dates to the 17th century, with older origins, still preserved.Khmer Highway (Cambodia/Thailand): Connected the Khmer Empire, with temple ruins along it.Inca Road System (South America): Pre-Columbian trail system in the Andes, partly preserved.

The speed will reach 75 kilometers per hour. The bulletin states, ‘Due to the effect of the deep pressure area, stormy winds with a speed of 40 to 50 kilometers per hour to 60 kilometers per hour are likely to blow in the central Bengal and adjoining northern Bay of Bengal from October 1. From the afternoon of October 2 to the morning of October 3, this speed will gradually increase in the west-central and adjoining northwest Bay of Bengal from 55-65 kilometers per hour to reach 75 kilometers per hour.’ IMD has also suggested hoisting ‘Local Warning Signal Number-Three’ (LC-3) at all ports of the state.

Rainfall warnings for various states and dates:
According to its latest forecast, IMD has said that on October 2, most places in coastal Andhra Pradesh may experience light to moderate rain, with some places seeing heavy to very heavy rainfall. Additionally, most places in Odisha may also see light to moderate rain, with some places expected to receive heavy to very heavy rainfall. On October 3, heavy to very heavy rainfall is also expected at some places.In Gangetic West Bengal, on October 2 and 3, most places may have light to moderate rain, with some places experiencing heavy to very heavy rainfall. Following this, on October 4, some places could see heavy rainfall. Furthermore, in Sub-Himalayan West Bengal, some places may have heavy rainfall on October 2, with heavy to very heavy rainfall expected at some places on October 3 and 4.”Here is the list of some of the oldest roads in the world that still exist:

In Jharkhand, on October 2, light to moderate rainfall is expected at many places, with some places seeing heavy rain, and on October 3 and 4, most places may experience light to moderate rainfall. In Bihar, heavy rain is expected at some places on October 2, and from October 3 to 5, heavy to very heavy rainfall is likely at some places. Additionally, in Chhattisgarh, eastern Uttar Pradesh, and eastern Madhya Pradesh, heavy rainfall is predicted at several places on October 3 and 4.Possibility of a unique event
IMD has said that at the same time, a low-pressure area has formed in the Arabian Sea, moving northeastwards towards Dwarka and the Gujarat coast. Additionally, a western disturbance is becoming active over northern India. Due to these, a historic weather event is likely to occur in North India during October 4 to 8. According to the department, there is a possibility of these three systems interacting with each other. This will be a very unique event, potentially causing record-breaking rainfall in Punjab, Uttarakhand, Himachal Pradesh, and surrounding states.”Here is the translation in English:In Jharkhand, on October 2, light to moderate rainfall is expected at many places, with some places experiencing heavy rain, and on October 3 and 4, most places may receive light to moderate rainfall. In Bihar, heavy rain is likely at some places on October 2, and from October 3 to 5, heavy to very heavy rain may occur at some places. Additionally, in Chhattisgarh, eastern Uttar Pradesh, and eastern Madhya Pradesh, heavy rain is forecast at several places on October 3 and 4.Possibility of a unique event:
IMD has said that at the same time, a low-pressure area has formed in the Arabian Sea, moving northeast towards Dwarka and the Gujarat coast. Besides, a western disturbance is also becoming active over northern India. Because of these, a historic weather event is likely in North India from October 4 to 8. According to the department, a collision of these three systems may happen. This will be a very unique event, potentially causing record-breaking rainfall in Punjab, Uttarakhand, Himachal Pradesh, and nearby states.

An intensified cyclonic circulation reaching 75 km/h is classified as a “Cyclonic Storm” by the India Meteorological Department (IMD). The “unique alert” likely refers to the multi-stage color-coded warning system designed to give increasingly urgent alerts as a storm develops. 

Four Stage Warning

The cyclone warnings are issued to state government officials in four stages. The First Stage warning known as “PRE CYCLONE WATCH” issued 72 hours in advance contains early warning about the development of a cyclonic disturbance in the north Indian Ocean, its likely intensification into a tropical cyclone and the coastal belt likely to experience adverse weather. This early warning bulletin is issued by the Director General of Meteorology himself and is addressed to the Cabinet Secretary and other senior officers of the Government of India including the Chief Secretaries of concerned maritime states.

The Second Stage warning known as “CYCLONE ALERT” is issued at least 48 hrs. in advance of the expected commencement of adverse weather over the coastal areas. It contains information on the location and intensity of the storm likely direction of its movement, intensification, coastal districts likely to experience adverse weather and advice to fishermen, general public, media and disaster managers. This is issued by the concerned ACWCs/CWCs and CWD at HQ.

The Third Stage warning known as “CYCLONE WARNING” issued at least 24 hours in advance of the expected commencement of adverse weather over the coastal areas. Landfall point is forecast at this stage. These warnings are issued by ACWCs/CWCs/and CWD at HQ at 3 hourly interval giving the latest position of cyclone and its intensity, likely point and time of landfall, associated heavy rainfall, strong wind and storm surge alongwith their impact and advice to general public, media, fishermen and disaster managers.

The Fourth Stage of warning known as “POST LANDFALL OUTLOOK” is issued by the concerned ACWCs/CWCs/and CWD at HQ at least 12 hours in advance of expected time of landfall. It gives likely direction of movement of the cyclone after its landfall and adverse weather likely to be experienced in the interior areas.

Different colour codes as mentioned below are being used since post monsoon season of 2006 the different stages of the cyclone warning bulletins as desired by the National Disaster Management.

Stage of warning	Colour code
Cyclone Alert	Yellow.
Cyclone Warning	Orange.
Post landfall out look	Red.

During disturbed weather over the Bay of Bengal and Arabian Sea, the ports likely to be affected are warned by concerned ACWCs/CWCs by advising the port authorities through port warnings to hoist appropriate Storm Warning Signals. The Department also issues “Fleet Forecast” for Indian Navy, Coastal Bulletins for Indian coastal areas covering up to 75 km from the coast line and sea area bulletins for the sea areas beyond 75 km. The special warnings are issued for fishermen four times a day in normal weather and every three hourly in accordance with the four stage warning in case of disturbed weather.

The general public, the coastal residents and fishermen are warned through State Government officials and broadcast of warnings through All India Radio and National Television (Doordarshan) telecast programmes in national and regional hook-up. A system of warning dissemination for fishermen through World Space Digital Based radio receivers is being planned.

Cyclone Awareness

• Do’s and Don’t

• Check houses, secure loose tiles by cementing wherever necessary, repair doors and windows.
• Check the area around the house. Remove dead or dying trees, anchor removable objects like lumber piles, loose bricks, garbage cans, sign-boards, loose zinc sheets etc.
• Keep some wooden boards ready so that glass windows can be boarded.
• If you do not have wooden boards handy, paste paper strips on glasses to prevent splinters flying into the house.
• Keep a hurricane Lantern filled with kerosene, flash light and enough dry cells and keep them handy.
• Promptly demolish condemned buildings.
• Those who have radio sets should ensure that the radio is fully serviceable. In the case of transistors an extra set of batteries should be kept handy.
• Keep your radio on and listen to latest weather warnings and advisories from the nearest AIR station. Pass the information to others.
• Pass only the official information you have got from the radio to others.
• Get away from low lying beaches or other locations which may be swept by high tides or storm waves. Leave sufficiently early before your way to high ground gets flooded. Do not delay and run the risk of being marooned.
• If your house is out of danger from high tides and flooding from the river, and it is well built, it is then probably the best place. However, please act promptly if asked to evacuate.
• Be alert for high water in areas where streams of rivers may flood due to heavy rains.
• Get extra food, especially things which can be eaten without cooking or with very little preparation. Store extra drinking water in suitably covered vessel.
• If you are in one of the evacuation areas, move your valuable articles to upper floors to minimise flood damage
• Check on everything that might blow away or be torn loose. Kerosene tins, cans, agricultural implements, garden tools, road signs and other objects become weapon of destruction in strong winds. Remove them and store them in a covered room.
• Be sure that a window or door can be opened on the lee side of the house i.e. the side opposite the one facing the wind.
• Make provisions for children and adults requiring special diets.
• If the centre of’ ‘eye’ of the storm passes directly over your place, there will be a lull in the wind and rain, lasting for half an hour or more. During this period stay in safe place. Make emergency repairs during the lull period if necessary, but remember that strong wind will return suddenly from the opposite direction, frequently with even greater violence.
• Be calm. Your ability to meet emergency will inspire and help others.
• You should remain in shelters until informed by those in charge that you may return home.
• Any loose and dangling wire from the lamp post should be strictly avoided.
• People should keep away from disaster areas unless you are required to assist.
• Anti-social elements should be prevented from doing mischief and reported to the police.
• Cars, buses, lorries and carts should be driven carefully.
• The houses and dwellings should be cleared of debris
• The losses should be reported to the appropriate authorities.
• Relatives should be promptly informed about the safety of persons in the disaster area.

Don’ts

• Avoid being misled by rumours.
• Don’t leave shelters until informed by the rescue personals.
• Don’t leave the safer place during lull, however minor repairs can be carried out.
• Don’t touch the loose and dangling wire from lamp post, it may have electric current.

Frequently Asked Questions on Tropical Cyclones and Marine Weather Services

1. What is a tropical cyclone?
   A tropical cyclone (TC) is a rotational low-pressure system in tropics when the central
   pressure falls by 5 to 6 hPa from the surrounding and maximum sustained wind speed
   reaches 34 knots (about 62 kmph). It is a vast violent whirl of 150 to 800 km, spiraling
   around a centre and progressing along the surface of the sea at a rate of 300 to 500 km a
   day.
   The word cyclone has been derived from Greek word ‘cyclos’ which means ‘coiling of
   a snake’. The word cyclone was coined by Henry Piddington who worked as a
   Rapporteur in Kolkata during British rule. The terms “hurricane” and “typhoon” are
   region specific names for a strong “tropical cyclone”. Tropical cyclones are called
   “Hurricanes” over the Atlantic Ocean and “Typhoons” over the Pacific Ocean.

2. Why do ‘tropical cyclones’ winds rotate counter-clockwise (clockwise) in the
   Northern (Southern) Hemisphere?
   The reason is that the earth’s rotation sets up an apparent force (called the Coriolis
   force) that pulls the winds to the right in the Northern Hemisphere (and to the left in the
   Southern Hemisphere). So, when a low pressure starts to form over north of the
   equator, the surface winds will flow inward trying to fill in the low and will be
   deflected to the right and a counter-clockwise rotation will be initiated. The opposite (a
   deflection to the left and a clockwise rotation) will occur south of the equator.
   This Coriolis force is too tiny to effect rotation in, for example, water that is going
   down the drains of sinks and toilets. The rotation in those will be determined by the
   geometry of the container and the original motion of the water. Thus, one can find both
   clockwise and counter-clockwise flowing drains no matter what hemisphere you are
   located. If you don’t believe this, test it out for yourself.
3. What does “maximum sustained wind” mean? How does it relate to gusts in
   tropical cyclones?
   India Meteorological Department (IMD) uses a 3 minutes averaging for the sustained wind. The maximum sustained wind mentioned in the bulletins used by IMD is the highest 3 minutes surface wind occurring within the circulation of the system. These surface winds are observed (or, more often, estimated) at the standard meteorological height of 10 m (33 ft) in an unobstructed exposure (i.e., not blocked by buildings or trees).
   The National Hurricane Centre uses a 1-minute averaging time for reporting the
   sustained. Some countries also use 10 minutes averaging time for this purpose. While, one can utilize a simple ratio to convert from peak 10-minute wind to peak 1 minute wind or 3-minute wind, such systematic differences to make inter-basin comparison of tropical cyclones around the world is problematic. Howeverthere is no significant
4. difference between the maximum sustained winds reported in different basis with
5. different averaging method.
6. What is the energy potential of a Tropical Cyclone?
   Tropical Cyclone can be compared to a heat engine. The energy input is from warm
   water and humid air over tropical oceans. Release of heat is through condensation of
   water vapour to water droplets/rain. Only a small percentage (3%) of this released
   energy is converted into Kinetic energy to maintain cyclone circulation (windfield). A
   mature cyclone releases energy equivalent to that of 100 hydrogen bombs.
7. How are low pressure system classified in India? What are the differences between low, depression and cyclone?
   The low-pressure systems over Indian region are classified based on the maximum sustained winds speed associated with the system and the pressure deficit/ number of closed isobars associated with the system. The pressure criteria are used when the system is over land and wind criteria is used, when the system is over the Sea. The system is called as low if there is one closed isobar in the interval of 2 hPa. It is called depression, if there are two closed isobars, a deep depression, if there are three closed isobars and cyclonic storm if there are four or more closed isobars. The detailed
   classification based on wind criteria are given in the Table below. Considering wind criteria, the system with wind speed of 17-27 knots is called as depression and the low pressure system with maximum sustained 3 minutes surface winds between 28-33 knots is called a deep depression. The system with maximum sustained 3 minutes surface winds of 34 knots or more is called as cyclonic storm.
   System Pressure deficient
   hPa w.r.t T No.
   Associated wind
   speed Knots (Kmph)
   Low pressure area 1.0 <17(<31)
   Depression 1.0- 3.0 17-27 (31-49)
   Deep Depression (DD) 3.0 – 4.5 28-33 (50-61)
   Cyclonic Storm (CS) 6.1-10.0 34-47 (62-88)
   Severe Cyclonic Storm
   (SCS)
   15.0 48-63 (89-117)
   Very Severe Cyclonic
   Storm (VSCS)
   20.9-29.4 64-89 (118-166)
   Extremely Severe Cyclonic
   Storm (ESCS)
   40.2-65.6 90-119 (167-221)
   Super Cyclonic Storm ≥ 80.0 ≥ 120 (≥ 222)

6. Are all cyclonic storms equally dangerous?
   No, all cyclonic storms are not equally dangerous. More the pressure drops at the
   central region more will be the severity of the storm. The cyclonic storms are generally
   categorized according to the maximum wind associated with the storm. If the maximum
   wind is between 34 – 47 knots (about 62-88 kmph) it is called a Cyclonic storm. Severe
   Cyclonic storm will have maximum wind speed between 48 – 63 knots (about 89-117
   kmph). If the maximum wind is 64-89 knots it will be called a very severe Cyclonic
   storm. If the maximum wind is 90-119 knots it will be called as Extremely Severe
   Cyclonic storm and when the wind is 120 knots and above it will be called super
   cyclonic storm. There is very little association between intensity (either measured by
   maximum sustained winds or by the lowest central pressure) and size (measured by
   radius of gale force winds)
7. What is the intensity of a cyclone?
   Intensity of a cyclone can be derived as the near-surface maximum wind speed around the circulation centre, or as the minimum surface pressure at the tropical cyclone pressure centre. The intensity classification of cyclone as per their wind speed and pressure defect is given in the table above.
8. What are the super cyclone, super-typhoon, a major hurricane and an Intense
   hurricane?
   When the maximum sustained 3 minutes surface winds are more than 119 knots, the low pressure system is called as “super cyclone” over north Indian Ocean. Similarly, “Super-typhoon” is a term utilized by the U.S. Joint Typhoon Warning Centre for typhoons that reach maximum sustained 1 minute surface winds of at least 130 knots (65 m/s). This is the equivalent of a strong Saffir-Simpson category 4 or category 5 hurricane in the Atlantic basin or a category 5 severe tropical cyclone in the Australian basin.
9. What is landfall of a cyclone?
   Landfall is the event of a tropical cyclone coming onto land after being over water. A tropical cyclone is classified as making landfall when the center of the storm moves across the coast; in strong tropical cyclones this is when the eye moves over land. This is where most of the damage occurs within a mature tropical cyclone as most of the damaging aspects of these systems are concentrated near the eye-wall. Such effects include the peaking of the storm surge, the core of strong winds comes on shore, and heavy flooding rains. These coupled with high surf can cause major beach erosion.
   When a tropical cyclone makes landfall, the eye closes in upon itself due to the
   weakening process, which causes surf to decrease. Maximum sustained wind will
   naturally decrease as the cyclone moved inland due to frictional differences between

water and land with the free atmosphere.
A “landfall” should not be confused with a direct hit, as a direct hit is where the core of high winds (or eye-wall) comes onshore but the center of the storm may stay offshore.
The effects of this are similar to a landfall, as this term is used when the radius of
maximum wind within a tropical cyclone moves ashore. These effects are; high surf,
heavy rains that may cause flooding, water build up along the coast with minor storm
surge, coastal beach erosion, high winds, and possibly severe weather.

10. What is radius of maximum wind of a Tropical cyclone?
    The radius of maximum wind (RMW) of a tropical cyclone is defined to be the distance between the center of the cyclone and its band of strongest winds. It is considered an important parameter in atmospheric dynamics and tropical cyclone forecasting.
11. How is the radius of maximum wind determined?
    Aircraft
    The RMW is traditionally measured by reconnaissance aircraft in the Atlantic basin. It can also be determined on weather map as the distance between the cyclone center and the system’s greatest pressure gradient.
    A. Satellite
    The distance between the coldest cloud top temperature and the warmest temperature within the eye, in infrared satellite imagery, is one method of determining RMW. The reason why this method has merit is that the strongest winds within tropical cyclone tend to be located under the deepest convection, which is seen on satellite imagery as the coldest cloud top
12. What does the RMW help?
    The radius of maximum wind helps determine the direct strikes of tropical cyclones. Tropical cyclones are considered to have made a direct strike to a landmass when a tropical cyclone passes close enough to a landmass that areas inside the radius of maximum wind are experienced on land.
    The highest storm surge is normally coincident with the radius of maximum wind.
    Because the strongest winds within a tropical cyclone lie at the RMW, this is the region of a tropical cyclone which generates the dominant waves near the storm, and ultimately ocean swell away from the cyclone.
13. What is radius of maximum reflectivity?
    The radial distance from the Tropical cyclone centre to the point of maximum
    reflectivity is known as the radius of maximum reflectivity.
14. Where do Tropical Cyclones form?

The tropical cyclones form over ocean basins in lower latitudes of all oceans except
south Atlantic and southeast Pacific. The tropical cyclones develop over the warm
waters of the Bay of Bengal and the Arabian Sea. The favourable ocean basins for
development of cyclonic storms are shown in the figure. TC breeding grounds are
located over certain ocean basins. Arrows indicate average trajectories over different
basins.

15. What is the size of a tropical cyclone over the north Indian Ocean?
    The size of a Tropical Cyclone over Indian seas varies from 50-100 km radius to 2000 km with an average of 300 –600 km.
16. What is the structure of a Tropical Cyclone?
    A fully developed tropical cyclone has a central cloud free region of calm winds,
    known as the “eye” of the cyclone with diameter varying from 10 to 50 km.
    Surrounding the eye is the “wall cloud region” characterized by very strong winds and torrential rains, which has the width of about 10 to 150 km. The winds over this region rotate around the centre and resemble the “coils of a snake”. Wind speed fall off gradually away from this core region, which terminate over areas of weaker winds with overcast skies and occasional squall. There may be one or more spiral branch in a cyclone where higher rainfall occurs. The vertical extent of the cyclone is about 15 km. The INSAT imagery of Odisha Super cyclone on 29th October, 1999 is shown in the figure below.