Hailstorm: How Hail Forms, Where India Gets It and How Crop Loss Is Insured

A hailstorm is a thunderstorm that drops balls or lumps of ice, called hailstones, instead of, or along with, rain. The World Meteorological Organization puts the usual hailstone at 5 to 50 mm across, and it forms only inside a towering cumulonimbus cloud whose updrafts can hold ice aloft long enough to grow. In India the damage peaks between February and May, when hail can flatten ripening wheat, mustard and gram, strip orchards and kill livestock within minutes over a strip only a few kilometers wide.

Two pictures of hail mislead most readers. The first treats it as a winter thing, frozen rain from cold weather, when hail is really a product of warm, unstable air and strong convection. The second is the textbook ping-pong story, in which a hailstone gets its layers by bouncing up and down through the cloud. Researchers at the US National Severe Storms Laboratory say the layers come from changing temperature and water conditions along the stone’s path, not from simple up-and-down trips. This note sorts out both, then follows hail into Indian fields, warnings and crop insurance.

What a hailstorm is

A hailstorm is defined by what falls, not by how hard it rains. The WMO’s International Cloud Atlas describes hail as precipitation of ice particles that are spheroidal, conical or irregular, usually 5 to 50 mm in diameter, and it adds that hail always falls as showers, generally in heavy thunderstorms. Anything smaller belongs to other categories such as small hail or ice pellets.

How hail forms inside a cumulonimbus cloud

Hail needs three things at once: a strong updraft, plenty of supercooled water and a cloud tall enough to reach well below freezing. NCERT’s chapter on atmospheric circulation calls a thunderstorm a well-grown cumulonimbus cloud and says hail forms when such clouds extend to heights where sub-zero temperatures prevail. Supercooled water is liquid water colder than 0°C that hasn’t frozen yet because it has nothing to freeze onto. A tall storm cloud is full of it.

The sequence, as NSSL describes it, runs like this:

• Lift. The updraft carries raindrops or small ice particles high into air far below freezing.
• Embryo. A drop freezes, or a soft ice pellet forms, and becomes the hailstone’s nucleus; the WMO says the nucleus is usually a few millimeters to a centimeter across.
• Growth. The stone collides with supercooled drops, which freeze onto its surface; the longer it stays in the water-rich zone, the bigger it gets.
• Fall. When the stone grows too heavy for the updraft, or the updraft weakens, gravity wins and it falls.

The layers are where the textbook picture slips. When drops freeze instantly on contact they trap air bubbles and make cloudy ice; when they freeze slowly the air escapes and the ice is clear. A stone drifting sideways across an updraft meets different temperatures and water contents, and that is what builds the alternating rings. NSSL also points out that hailstones don’t grow at the very top of the cloud, because above about -40°C all the water has already frozen and there is nothing left to collect. The WMO adds that most stones show no more than 5 layers, though very large ones can have 20 or more.

Speed is the other thing people underestimate. NSSL’s figures, from wind-tunnel tests on casts of real hailstones, give 9 to 25 mph (about 15 to 40 km/h) for stones under an inch, 25 to 40 mph for stones of 1 to 1.75 inches and 44 to 72 mph for the 2 to 4 inch stones of the strongest storms. That is why a short burst of hail can do more damage to a wheat crop than a whole day of heavy rain.

Hail, sleet and snow are different things

The three are easy to mix up because all of them are frozen. NCERT keeps them apart by how they form:

• Snow forms as ice crystals directly in cold cloud, in the hexagonal flakes of winter precipitation.
• Sleet forms when raindrops falling from a warm layer freeze in a cold layer near the ground; NCERT notes the pellets are never bigger than the raindrops they came from.
• Hail grows inside a convective storm by collecting supercooled water, so it can become far bigger than any raindrop, and it can fall on a hot afternoon.

The size rule is the quick test. Ice the size of a lemon cannot be frozen rain.

Where and when India gets hail

India’s hail follows the pre-monsoon and late-winter weather, not the coldest months. The fullest study comes from four IMD Pune scientists, N. Chattopadhyay, S. Sunitha Devi, Gracy John and V. R. Choudhari, who analyzed 35 years of records from 1981 to 2015 and published the results in Mausam in January 2017. NSSL, looking from the US, names India alongside China, Russia and northern Italy as places with damaging hailstorms.

The study’s main findings on geography:

• Maharashtra recorded hail in 31 of the 35 years and has the highest probability of a hail year, 91 to 95%. Its worst run was 11 hail days between 24 February and 14 March 2014.
• The north gets hail mostly from March to May: Himachal Pradesh logged 13 hail days in May 1994, and Punjab, Haryana, Uttar Pradesh and Rajasthan each saw hail in 20 or more years.
• The east and northeast have their own season of evening storms; earlier work quoted in the study found about 10 hailstorms a year over extreme northeast Assam.
• The least prone, at 6 to 10%, were Gujarat, Chhattisgarh, Tamil Nadu, Tripura, Meghalaya, Sikkim and Nagaland.

The weather patterns behind these outbreaks explain why the timing is so consistent. The same paper lists upper-level divergence from the subtropical westerly jet stream, a weak north-south line of wind discontinuity that forces low-level air to converge and western disturbances that pull in moisture from the Arabian Sea. Put simply, warm moist air near the ground meets cold, fast-moving air aloft, and the atmosphere becomes unstable enough to build tall storms. The 2014 outbreak, the authors write, came from an unusual southward shift of the jet’s core along with a deep westerly trough. The jet itself is covered in the note on Rossby waves and jet streams.

The eastern storms belong to the same family as the Nor’westers of Bengal and Assam, which NCERT says are locally called Kalbaisakhi. The pre-monsoon season of storms is described in the note on seasons in India.

Why hail hurts Indian farmers so much

Hail hits Indian agriculture at the worst possible moment. Late February and March is when rabi crops are flowering, filling grain or waiting to be harvested, so a 15-minute storm can undo a season’s work. The note on rabi crops gives the crop calendar this damage cuts across.

The 2015 season shows the scale. The Mausam study reproduces state estimates, as on 16 April 2015, of crop area hit by hail and unseasonal rain: 22.24 lakh hectares in Haryana, 16.89 lakh hectares in Rajasthan and 9.89 lakh hectares in Maharashtra. Its crop-by-crop table describes the kinds of damage that follow:

• Lodging, where wind and hail flatten wheat, mustard and gram so they can’t be harvested cleanly.
• Shattering and fruit drop, which strips grain from ears and fruit from mango, grape and orange trees.
• Quality loss, as wet grain and seed take on fungal disease and lose germination and storage life.

Hail is also harder on farmers than drought in one specific way: it is patchy. A storm can wreck one village and spare the next, so area-wide yield data often miss it entirely. That single fact shaped how crop insurance treats hail.

How the government warns and compensates

India handles hail through three separate systems: warnings from the India Meteorological Department, disaster relief through the state funds and insurance through PMFBY. Each answers a different question.

Warnings and nowcasts

IMD issues hailstorm warnings as part of its daily multi-hazard forecasts, and NDMA’s guidelines list hailstorm among the phenomena covered by the color-coded warning system of green, yellow, orange and red. Because a hail cell lives for less than an hour, the most useful tool is the nowcast, which the Mausam paper defines as a description of current weather with forecasts extrapolated 0 to 6 hours ahead, built on Doppler weather radar, automatic weather stations and half-hourly satellite images. The India Meteorological Department note covers the radar network and warning chain.

The same study lists the farm advice that goes out with these warnings:

• spread hail nets over orchards;
• put hail caps over nurseries and young plants;
• prop up sugarcane and support banana and young fruit plants against wind;
• move harvested produce under cover.

Relief under the disaster funds

Hailstorm is one of the 12 notified natural calamities for which states can spend from the State Disaster Response Fund and, in severe cases, seek help from the National Disaster Response Fund. Arthapedia, the Indian Economic Service’s reference, notes that the Ministry of Agriculture, not the Home Ministry, handles drought, hailstorm, pest attack and cold wave and frost. Relief is a flat input subsidy for loss; it isn’t insurance, and it doesn’t depend on a premium. The money flows are explained in the note on disaster financing.

Insurance under PMFBY

Under the Pradhan Mantri Fasal Bima Yojana, hailstorm is a localized calamity, and that changes how a claim works. Most PMFBY claims are settled on an area basis, using crop-cutting data for a whole insurance unit. For localized risks and post-harvest losses, the guidelines make the affected insured field of the individual farmer the unit of loss assessment. A farmer whose field alone was hit can still claim.

The key rules:

• Localized risks covered are hailstorm, landslide, inundation, cloudburst and natural fire due to lightning.
• Post-harvest cover runs up to 14 days from harvest for crops left cut and spread to dry in the field, against hailstorm, cyclone, cyclonic rain and unseasonal rain.
• Intimation must reach the insurer, the bank or the state within 72 hours, raised from 48 hours in the revised operational guidelines.

PMFBY’s structure, premiums and criticisms are in the full PMFBY note, and enrolment runs through the official PMFBY portal.

Hailstorms today

Hailstorms carry the same legal standing as before: a notified calamity for relief and a localized risk for insurance. The live questions are forecasting and frequency.

On 29 March 2026, an IMD press release reported hail at isolated places over Mizoram and forecast isolated hailstorms over northwest India on 29-30 March and over central India on 30-31 March. The systems it named were a western disturbance over north Iran and the Caspian Sea and a subtropical westerly jet with core winds near 80 knots at about 12.6 km. It is the textbook hail setup, a western disturbance plus the jet, on an ordinary spring week.

In May 2026, severe thunderstorms with dust storms, lightning and hail killed more than 100 people across Uttar Pradesh, as the explainer on what triggered the Uttar Pradesh thunderstorms records. Whether Indian hail is becoming more frequent is less settled. The 2017 Mausam authors themselves noted that judging changes in hail frequency is difficult because the records are patchy, and that caution still applies.

How to study hailstorm for exams

Hailstorm sits in two parts of the syllabus at once. In GS Paper I it belongs to climatology, alongside thunderstorms, cloud types and forms of precipitation. In GS Paper III it reappears under disaster management and agriculture, where crop insurance and relief norms live. Prelims draws on both, and the site’s Prelims question bank counts 82 of its 1,403 questions under Geography and 249 under Environment.

Mains tests the theme from the warning and insurance side more than the physics. Mains 2022 GS Paper I asked candidates to “Discuss the meaning of colour-coded weather warnings for cyclone prone areas given by India Meteorological Department.” and Mains 2016 GS Paper III asked them to “Given the vulnerability of Indian agriculture to vagaries of nature, discuss the need for crop insurance and bring out the salient features of the Pradhan Mantri Fasal Bima Yojana (PMFBY).” A hailstorm example strengthens both answers.

Revise these until they’re automatic:

• 5 to 50 mm: the usual hailstone diameter in the WMO definition.
• Cumulonimbus: the only cloud that makes hail; it needs strong updrafts and sub-zero tops.
• Supercooled water: liquid below 0°C that freezes onto the stone and makes it grow.
• February to May: India’s hail season, with the biggest outbreaks in March.
• Maharashtra: the most hail-prone state in the 1981-2015 record; Vidarbha and Marathwada take the brunt.
• Localized calamity: PMFBY assesses hail loss per field, with intimation within 72 hours.
• Notified calamity: hailstorm qualifies for SDRF and NDRF relief, handled by the Ministry of Agriculture.

Three confusions cost marks. Hail isn’t frozen rain; that is sleet, and it never grows bigger than a raindrop. Hail isn’t a cold-weather event; it needs warm, moist, unstable air at the surface. And the layered hailstone doesn’t prove a ping-pong path; it records changing conditions along the stone’s route.

Hailstorm rewards the aspirant who connects the cloud to the field. Know the updraft and the supercooled water, place the storm on a March afternoon in Vidarbha, and then follow the loss into PMFBY’s field-level claim. An answer that does all three shows the examiner that physical geography and agricultural policy are one subject.

Frequently Asked Questions

Practice Questions

Prelims

1. Consider the following statements about hail: 1. Hailstones grow by collecting supercooled water drops inside a cumulonimbus cloud. 2. Hailstones cannot be larger than the raindrops from which they form. Which of the statements given above is/are correct?

• (a) 1 only
• (b) 2 only
• (c) Both 1 and 2
• (d) Neither 1 nor 2

Answer: (a) Statement 2 describes sleet; hail grows by accretion and can be far larger than a raindrop.

2. Consider the following statements about crop loss from hailstorms under the Pradhan Mantri Fasal Bima Yojana: 1. Loss from hailstorm as a localized calamity is assessed on the individual insured field. 2. Hailstorm is covered for post-harvest losses on crops kept cut and spread in the field. 3. The farmer must report the loss within 7 days. Which of the statements given above are correct?

• (a) 1 and 2 only
• (b) 2 and 3 only
• (c) 1 and 3 only
• (d) 1, 2 and 3

Answer: (a) The intimation window is 72 hours, not 7 days.

3. In India, hailstorms are most frequent during which period?

• (a) June to August
• (b) February to May
• (c) October to November
• (d) December to January

Answer: (b) Hail peaks in late winter and the pre-monsoon season, when rabi crops are maturing.

4. Which one of the following cloud types produces hail?

• (a) Cirrostratus
• (b) Nimbostratus
• (c) Cumulonimbus
• (d) Altocumulus

Answer: (c) Only the cumulonimbus has the strong updrafts and sub-zero tops that hail needs.

5. Which of the following is a notified natural calamity for assistance under the State Disaster Response Fund?

• (a) Heat island effect
• (b) Hailstorm
• (c) Coastal erosion
• (d) Air pollution episode

Answer: (b) Hailstorm is among the 12 notified calamities; the others listed are not on the central list.

Mains

1. Discuss the meaning of colour-coded weather warnings for cyclone prone areas given by India Meteorological Department. (10 marks, 150 words) Previous year: Mains 2022, GS Paper I.
2. Explain the process of hail formation in a cumulonimbus cloud and account for the concentration of hailstorms in India between February and May. (10 marks, 150 words)
3. Hailstorms are localized in space but severe in their impact on Indian agriculture. Examine the damage they cause to rabi and horticultural crops and the protective measures available to farmers. (15 marks, 250 words)
4. Why is hailstorm treated as a localized calamity under the Pradhan Mantri Fasal Bima Yojana? Critically examine how far the field-level assessment of hail losses serves small farmers. (15 marks, 250 words)
5. Assess the role of nowcasting and Doppler weather radar in reducing losses from hailstorms and severe thunderstorms in India. (10 marks, 150 words)