Hail

What is Hail?

Hail is precipitation in the form of solid balls or irregular lumps of ice produced exclusively by severe thunderstorms. Unlike snow, sleet or freezing rain, hailstones grow inside clouds through a recycling process that requires very strong updrafts — usually found in supercells or vigorous multi-cell thunderstorms.

A hailstone can range from a few millimetres (pea-sized) to over 20 centimetres (volleyball-sized in record cases). The world’s heaviest recorded hailstone fell in Gopalganj, Bangladesh on 14 April 1986, weighing 1.02 kg — heavier than a small brick. That single hailstorm killed 92 people.

In South Asia, hail is associated with pre-monsoon Nor’wester storms (Kal Baisakhi) and occasional severe monsoon storms. It is a major agricultural hazard — wheat, mustard, gram, fruit orchards (apples, mangoes, grapes) and standing rabi crops can be destroyed in minutes.

How hailstones form

Hail formation requires four ingredients:

1. A deep cumulonimbus cloud extending well above the freezing level (5–6 km).
2. Strong updrafts of 50+ km/h that can keep particles aloft.
3. Plenty of supercooled liquid water (water that remains liquid below 0°C).
4. Time — typically 5–10 minutes inside the cloud.

The process:

1. An ice nucleus (small ice crystal or frozen droplet) forms in the upper cold part of the cloud.
2. Falls through supercooled water — gets coated with liquid that freezes on contact.
3. Strong updraft lifts it back up — adding another freezing layer.
4. Several updraft-downdraft cycles add concentric ice layers — visible if you cut a hailstone in half.
5. When the stone becomes too heavy for the updraft to support, it falls to the ground as hail.

The stronger the updraft, the larger the hailstones the storm can produce.

Hail in South Asia

The Indo-Gangetic plain and eastern India are South Asia’s hail hot spots, especially in March–May (pre-monsoon) when:

• Surface temperatures are 35–42°C.
• Bay of Bengal humidity flows in at low levels.
• Strong upper-level westerlies provide instability.

Regions with frequent severe hail:

• Bangladesh: Western and central districts (Dhaka, Mymensingh, Tangail, Gopalganj).
• West Bengal: Birbhum, Murshidabad, Burdwan, Hooghly.
• Bihar, Jharkhand, Odisha: Pre-monsoon storms.
• Assam, Meghalaya, Tripura: Severe Nor’westers.
• Madhya Pradesh, eastern UP: Pre-monsoon and post-monsoon hail.
• Pakistan: Eastern Punjab in spring.
• Himachal, Uttarakhand: Hailstorms in apple-growing belts.

Notable hailstorms:

• 1986 Gopalganj, Bangladesh: 92 deaths from 1 kg hailstones.
• 2014 Vidarbha, Maharashtra: Unseasonal February-March hail; 4,000 crore rupees crop damage; at least 28 deaths.
• 2023 Maharashtra: Pre-monsoon hail wiped out grape and mango crops.

Hailstone sizing

Approximate hailstone sizes:

US insurance records suggest hailstones of 2.5 cm (1 inch) are the threshold above which significant property damage occurs.

Hail’s economic impact

Agriculture:

• February-March 2014 Maharashtra hailstorms damaged standing wheat, jowar and gram.

Infrastructure:

• Vehicle damage from cricket-ball-sized hail can be severe.
• Roof damage common; concrete tiles cracked, metal sheets dented.

Crop insurance:

• PMFBY (India’s flagship crop insurance scheme) covers hail damage; payouts are a major reason farmers enrol.

Hail safety

If you are caught outside during a hailstorm:

1. Seek immediate shelter — even cricket-ball hail can cause concussion.
2. Cars are safer than open ground — but pull off the road; visibility drops.
3. Avoid windows in buildings.
4. Protect children and elderly — they are most at risk.
5. After the storm, watch for ice on roads — driving hazard.

For farmers:

• Cover sensitive crops with hail nets during pre-monsoon season.
• Subscribe to crop insurance.
• Monitor IMD’s severe-weather warnings.

Climate change and hail

Research suggests:

• Hailstone size is increasing in some regions due to stronger updrafts in warmer atmospheres.
• Hail season is becoming more erratic — unseasonal hail in winter and early spring is more common.
• Pre-monsoon hail in north India and Bangladesh is forecast to intensify in coming decades.

Frequently asked questions

Why does hail fall mostly in the warm season? Hail requires very strong thunderstorm updrafts — usually present in warm-season convection. Winter clouds are usually not deep or vigorous enough to recycle ice particles, although an intense western disturbance can still bring winter hail, as in January 2022 across northwest and central India. South Asia’s hail season is March–May (pre-monsoon thunderstorms) with occasional events in November.

Can hail damage solar panels? Yes — quality solar panels are typically tested to withstand 25 mm hail at 80 km/h. Larger hailstones can crack panels. Hail nets and protective covers reduce risk.

Why is South Asian hail concentrated in Bangladesh and eastern India? The combination of moist Bay of Bengal air at low levels and cold dry westerlies aloft creates extreme atmospheric instability — CAPE values often exceed 4,000 J/kg in pre-monsoon Nor’westers, supporting strong updrafts and hail.

Is there a way to prevent hail? Various attempts (cloud seeding with silver iodide, sonic cannons) have been tried for decades with mixed results. There is no scientifically proven hail prevention technique at scale. Insurance and physical protection (nets, shelters) remain the practical defences.

Where can I see severe-weather warnings for my city? Mausam Online displays precipitation forecasts and severe-weather codes (95–99 = thunderstorm) on every city page. NDMA’s Sachet app provides official severe-weather warnings. See Kolkata, Patna, Bhopal, Dhaka, Lahore.

Related terms

• Thunderstorm
• Cumulonimbus
• Precipitation
• Lightning
• Squall