How Is Hail Formed?


Photo via Flickr.

Hail is one of those neat weather phenomenons that happens in the Rockies.  Do you know how hail is formed and why it is common in the spring and summer?

As I’ve said before, I love the spring for many reasons.  A common spring feature is big changes in the weather from one day to the next or even during the same day.  One minute may be sunny and warm and the next cold with hail falling from the sky.

What is Hail?

Hail is a form of frozen precipitation.  In other words, it is like an ice cube that forms in the sky and then falls down to the ground.


A big, towering cumulonimbus cloud often brings thunderstorms. Photo via Flickr.

How Does Hail Form?

It forms when thunderstorm clouds or the currents that cause air to rise in thunderstorms, called updrafts, cause water droplets to rise up in the sky.  Eventually, those water droplets get above the freezing level.  Then the water droplets freeze and form a hailstone.

Once they are frozen more and more ice may gather onto it as additional water is attracted to it.  This will cause the hailstone to grow larger.  Finally, the hailstone becomes too heavy for the air to support it and it falls to the ground.


Photo via Flickr.

As the hailstone falls to the ground it may melt as it passes through warmer air.  Whether or not it makes it all the way to the ground and still is hail depends on how big it was to begin with among other factors.

Why is Hail Common In the Spring?

If you just read the above explanation about how it forms then you will understand that the main thing needed is a big thunderstorm.  Thunderstorms tend to happen most frequently in the spring and summer.

It can happen at anytime during the year, but it tends to occur in the spring and summer because there is enough sunshine to warm up the air and create the strong thunderstorms needed to form it.

Note – Hail is most common in the plains just to the east of the Rocky Mountains, but it can still and does occur in the mountains themselves.