No, hail is not simply frozen rain, although they both involve frozen water. Hail forms in a different way than rain and frozen rain (sleet). Here's a detailed explanation:
How Hail Forms
Hail is a form of frozen precipitation, and it develops through a unique process. According to the reference material, hail forms:
- Starting with embryos such as graupel (soft hail or snow pellets) or sleet.
- These embryos grow as they travel upwards in strong storm updrafts, accumulating supercooled water that freezes onto their surface.
- This process of water collection and freezing can lead to hailstones that vary from small pebbles to large, damaging stones.
Hail vs. Frozen Rain (Sleet)
The crucial difference is the process of formation:
| Feature | Hail | Sleet (Frozen Rain) |
|---|---|---|
| Formation | Forms in strong updrafts by accumulating frozen water layers on an embryo. | Forms when rain falls through a layer of freezing air near the ground. |
| Size | Can range from small to very large, often irregular shapes. | Typically small, like ice pellets, usually round or irregular shape. |
| Structure | Often displays layered structure, resembling an onion when cut open. | Generally a uniform structure or may contain a few layers if formed near ground |
Key Differences
Here's a summary of the key differences:
- Updrafts: Hail requires strong storm updrafts to develop, whereas sleet forms as rain falls through a freezing layer of air near the ground.
- Growth: Hail grows by repeatedly rising and falling in a storm cloud, collecting supercooled water that freezes onto the hailstone. Sleet simply freezes as it falls.
- Size and Structure: Hailstones are generally much larger than sleet pellets and can have layered structures. Sleet, as frozen rain, is smaller and simpler in structure.
Therefore, while both hail and sleet are forms of frozen precipitation, they form under different conditions and by different mechanisms. Hail isn't just frozen rain; it is a more complex process involving cycles of growth within storm clouds.
