NEW DELHI, November 1, 2026—India’s weather bulletins distinguish a low-pressure area, a depression, a deep depression, and a cyclonic storm by the system’s intensity, including its sustained wind speed. The categories describe the strength of a weather system; they do not, by themselves, tell residents exactly where it will make landfall, how much rain a district will receive, or whether every location along a coast faces the same danger. Understanding the difference helps readers interpret forecasts without treating an early-stage system as a guaranteed cyclone.
The government’s meteorological disaster handbook reproduces the North Indian Ocean classification used to describe low-pressure systems. A depression is associated with sustained winds of about 31–49 km/h; a deep depression with 50–61 km/h; and a cyclonic storm with 62–88 km/h. Stronger categories are severe cyclonic storm at roughly 89–117 km/h, very severe at 118–166 km/h, extremely severe at 167–221 km/h, and super cyclonic storm at 222 km/h or more. These ranges refer to sustained winds, not the strongest gust measured at one instant.
The thresholds are useful because they create a common language for forecasters, disaster managers, port authorities, transport operators, and the public. A system can strengthen from one category to another as the observations change, so the label in a bulletin is a snapshot of the assessment at that time. Readers should not rely on an old screenshot or social media graphic when the official bulletin may have been updated.
A low-pressure area is a region where atmospheric pressure is lower than its surroundings, encouraging air to converge and rise. If the atmosphere contains enough moisture and the surrounding winds are favorable, that rising air can support cloud growth and rainfall. Many low-pressure areas do not become cyclonic storms. Their eventual development depends on several interacting factors, including ocean heat, atmospheric moisture, wind shear, and the organization of thunderstorms around the center.
The word ‘low pressure’ therefore signals a developing weather feature, not a guaranteed disaster. The system’s location, movement, rainfall bands, and interaction with land all matter. A weak system may still bring significant rain if it moves slowly over a region or feeds moisture into a separate weather pattern. Conversely, a stronger system can have a very different impact depending on its track, size, forward speed, and the places exposed to its winds and rain.
Also read: Bay of Bengal Depression May Strengthen Near Andhra Coast
When a system reaches the cyclonic-storm threshold, it enters the category in which a name is assigned under the regional naming arrangement. Naming helps forecasters and the public identify a particular system across successive bulletins. It does not mean that the storm has reached its strongest possible intensity, and it does not determine the level of local risk by itself. A named storm may intensify further, weaken, change direction, or bring heavy rain well away from the point where its center crosses land.
Forecast confidence also changes over time. Satellite observations, weather radar, ocean measurements, surface stations, and numerical models help meteorologists estimate the system’s current structure and likely path. The forecast is updated as new observations arrive. A map showing one projected track should not be read as a precise line that the center must follow; the forecast cone or uncertainty range exists because the exact path cannot be known perfectly in advance.
Wind categories are important, but they do not measure every threat. Rainfall can trigger flash floods, river flooding, and landslides, especially where the ground is already saturated. Coastal systems can produce storm surge and waves that push seawater inland, while strong winds may damage roofs, trees, power lines, and communication networks. The effects vary by geography: a river basin, a low-lying coast, and a steep hillside can face different risks from the same weather system.
That is why a storm category should be read alongside local impact warnings. The IMD’s official portal provides warnings and district-level information, while state disaster-management agencies issue instructions for evacuation, shelter, transport, and public services. A higher wind category does not automatically mean every district will receive the same rainfall, and a lower category does not make flooding impossible. Local forecasts and official instructions are more useful for decisions than the name or category alone.
Also read: IMD Warns of Heavy Rain Across Several States as New Bay of Bengal System Develops
Readers may see different wind figures in reports from different weather agencies because the agencies may use different averaging periods or describe sustained winds and gusts separately. A short-lived gust can be substantially stronger than the sustained wind used to classify a cyclone. Numbers should therefore be compared only after checking what each figure measures, which observation period it covers, and whether it is a forecast or a measured value.
Units can also create confusion. Official bulletins may use kilometers per hour, meters per second, or knots. A rough conversion is 1 knot equal to about 1.852 km/h, but a converted number should not be presented with greater precision than the original forecast supports. If a news report quotes a wind speed, the useful question is whether it refers to the system’s sustained wind, a gust at a location, or the maximum expected at landfall.
Start with the bulletin’s issue time and the period it covers. Then identify the system’s current location, its direction of movement, the expected intensity over the next 24 to 72 hours, and the districts or coastal stretches mentioned in the impact warning. Check whether the bulletin describes a possibility, a high likelihood, or an observed change. Words such as ‘likely’ and ‘very likely’ communicate forecast confidence; they are not promises that an event will occur exactly as described.
Do not treat a single model graphic as an official warning. Forecast models can disagree, and an individual map may show one possible outcome rather than the forecaster’s full assessment. The IMD’s bulletins bring together observations and model guidance into a public forecast. For decisions about travel, fishing, schools, work, or evacuation, use the latest official local advisory and follow instructions from authorities responsible for the area.
Residents in areas named in an official warning should secure loose outdoor objects, keep phones charged, prepare essential medicines and drinking water, and know the location of the nearest designated shelter if evacuation is advised. People living near rivers, drains, steep slopes, or low-lying coasts should pay particular attention to local flood and landslide instructions. Fisherfolk should follow the specific marine warning rather than inferring sea conditions from a general land forecast.
Travellers should verify road, rail, ferry, and flight information directly with operators because weather disruptions can change quickly. Do not drive through floodwater, approach swollen streams to take photographs, or stand near the sea during rough conditions. These precautions are relevant even when a system is not classified as a severe cyclone. The practical risk depends on the local exposure and the combination of wind, rainfall, waves, and drainage conditions.
The next useful information is the updated IMD bulletin, not an unverified prediction about the exact landfall point. Watch for changes in the system’s category, movement, expected rainfall, and the list of districts under warning. If the system strengthens, the warning may change; if it weakens, rainfall or coastal hazards may still continue. The classification is one piece of the forecast, and local impact information should guide the response.
The central lesson is straightforward: categories make storm intensity easier to communicate, but they are not a substitute for location-specific forecasts. Knowing the difference between a depression and a cyclonic storm helps readers understand the language of a bulletin. Acting on the current official warning, preparing for local hazards and checking updates at the stated issue time are more reliable than relying on a single category label.
At what wind speed is a system classified as a cyclonic storm in India?
The classification table lists a cyclonic storm at sustained winds of about 62–88 km/h. The category is based on sustained wind, not a brief gust.
Does every depression become a cyclone?
No. A depression may strengthen, remain at its current intensity, or weaken. Development depends on oceanic and atmospheric conditions.
Where should people check current cyclone warnings?
Use the India Meteorological Department’s official portal and local district or state disaster-management advisories. Check the issue time because bulletins are updated.
Sources: National Remote Sensing Centre meteorological disaster handbook; India Meteorological Department official portal and warnings;