Hailstones are precipitation in the form of ice that forms during thunderstorms. According to reference information, they are formed when raindrops are carried upward by thunderstorm updrafts into extremely cold areas of the atmosphere and freeze. Hailstones then grow as they collide with liquid water drops, which subsequently freeze onto the hailstone's surface.
How Hailstones Form: A Step-by-Step Explanation
Here's a simplified breakdown of how hailstones develop:
- Updrafts: Strong updrafts within thunderstorms carry raindrops high into the atmosphere.
- Freezing Temperatures: At higher altitudes, the temperature drops significantly below freezing.
- Initial Freezing: These raindrops freeze into small ice particles.
- Growth: The ice particles (hailstones) collide with supercooled water droplets (water that remains liquid below freezing) that freeze onto the hailstone, causing it to grow larger.
- Cycle of Ascent and Descent: Hailstones may be repeatedly lifted by updrafts and fall back down through the storm, accumulating layers of ice each time. This is why hailstones often have a layered appearance when cut open.
- Falling to Earth: Eventually, the hailstone becomes too heavy for the updraft to support it, and it falls to the ground as hail.
Factors Influencing Hail Size
Several factors influence the size of hailstones:
- Updraft Strength: Stronger updrafts can keep hailstones suspended in the thunderstorm for longer, allowing them to grow larger.
- Supercooled Water Availability: The abundance of supercooled water in the storm is crucial for hailstone growth.
- Storm Duration: Longer-lasting thunderstorms provide more opportunities for hailstone development.
Understanding Hailstone Structure
Hailstones often display alternating layers of clear and opaque ice.
| Layer Type | Description |
|---|---|
| Clear Ice | Forms when water freezes slowly, allowing air bubbles to escape. |
| Opaque Ice | Forms when water freezes rapidly, trapping air bubbles within the ice. |
Why is hail dangerous?
- Damage to Property: Hail can cause extensive damage to vehicles, roofs, and other property.
- Agricultural Losses: Hailstorms can devastate crops, leading to significant economic losses for farmers.
- Personal Injury: Large hailstones can cause injuries to people and animals.
