What are the differences between snow and hail?

Answer 1

The main difference lies in how each is formed and what conditions are necessary for their formation.

SNOW:

Snow occurs when there are no layers above freezing higher up in the atmosphere. If temperatures remain below freezing for much of the troposphere, snow will fall. However, there may still be a somewhat warmer layer near the surface, with temps as high as 40ºF, and snow will still fall, though it will not stick to the ground.

HAIL:

Hail comes from strong thunderstorms and is usually not associated with snow. To understand how hail is formed, you must understand how a thunderstorm forms.

First, there needs to be warm moist air at the surface and cold dry air aloft (high in the atmosphere). The warm air will rise and when the temperature reaches the dew point, it will condense into a liquid droplet. This process continues and a cumulonimbus cloud is formed. These clouds are also known as "thunderclouds" because they produce lightning, heavy rain, hail and sometimes tornadoes.

Now, if there is enough wind shear (changing wind speeds and directions higher in the atmosphere), this thundercloud will begin to rotate. This is now called a "supercell thunderstorm". Nearly all tornadoes and large hail come from supercells.

Inside this supercell, an "updraft" of wind blows up and into the cloud from the ground, continually feeding the supercell with more warm-moist air. Updrafts in a supercell are tilted.

Now, there is also a "downdraft" of wind blowing down from the top of the storm cloud towards the ground. A downdraft exists because of the large amounts of falling precipitation.

Hail is precipitation that is formed when updrafts in thunderstorms carry raindrops upward into extremely cold areas of the atmosphere. Updrafts tend to be particularly strong in supercell thunderstorms.

The stronger the updraft, the larger the hail will be, the reason why is because updrafts and downdrafts work together. When the hail nucleus hits the updraft, it's carried upward high in the atmosphere where it freezes. Eventually it leaves the updraft and begins heading down to the ground due to gravity. Then, it will encounter the updraft once again and begin heading up as it did before. Each time this happens, another layer of ice is added to the hail because of cold temperatures high in the storm cloud. Eventually, the hail stone will be too heavy for the updraft to sustain it in the air and the hail stone will drop.

Answer 2

A flurry is a light snow storm and it is brief. Flurries do not last as long as a snow storm. A snow storm can cover the ground within seconds. The flurry can produce the measurement of snow.