Hail is precipitation that is formed when updrafts in thunderstorms carry raindrops upward into extremely cold areas of the atmosphere. Hail can damage aircraft, homes and cars, and can be deadly to livestock and people. One of the people killed during the March 28, 2000 tornado in Fort Worth was killed when struck by grapefruit-size hail. I have seen baseball and softball sized hail and can’t imagine the need to be out in that storm. The sound alone is pretty scary. The damage is worse – I had a brand new truck which looked like the feature image as far as the damage caused by hail.
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Strong updrafts create a rain-free “vault” underneath the leading edge of a supercell.
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Same cross-section as before but showing an idealized path of hail within cloud
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Hailstones grow by collision with supercooled water drops. (Supercooled drops are liquid drops surrounded by air that is below freezing which is a common occurrence in thunderstorms.) There are two methods by which the hailstone grows, wet growth and dry growth, and which produce the “layered look” of hail.
In wet growth, the hailstone nucleus (a tiny piece of ice) is in a region where the air temperature is below freezing, but not super cold. Upon colliding with a supercooled drop the water does not immediately freeze around the nucleus.
Instead liquid water spreads across tumbling hailstones and slowly freezes. Since the process is slow, air bubbles can escape resulting in a layer of clear ice.
With dry growth, the air temperature is well below freezing and the water droplet immediately freezes as it collides with the nucleus. The air bubbles are “frozen” in place, leaving cloudy ice.
Strong updrafts create a rain-free area in supercell thunderstorms. Meteorologists call this area a WER which stands for “weak echo region”.
This term, WER, comes from an apparently rain free region of a thunderstorm which is bounded on one side AND above by very intense precipitation indicted by a strong echo on radar.
This rain-free region is produced by the updraft and is what suspends rain and hail aloft producing the strong radar echo.
- The hail nucleus, buoyed by the updraft is carried aloft by the updraft and begins to grow in size as it collides with supercooled raindrops and other small pieces of hail.
- Sometimes the hailstone is blown out of the main updraft and begins to fall to the earth.
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If the updraft is strong enough it will move the hailstone back into the cloud where it once again collides with water and hail and grows. This process may be repeated several times.
- In all cases, when the hailstone can no longer be supported by the updraft it falls to the earth. The stronger the updraft, the larger the hailstones that can be produced by the thunderstorm.
Multi-cell thunderstorms produce many hail storms but usually not the largest hailstones. The reason is that the mature stage in the life cycle of the multi-cell is relatively short which decreases the time for growth.
However, the sustained updraft in supercell thunderstorms support large hail formation by repeatedly lifting the hailstones into the very cold air at the top of the thunderstorm cloud.
The stronger the updraft the larger the hailstone can grow. In all cases, the hail falls when the thunderstorm’s updraft can no longer support the weight of the ice.
Just another cold winter day…
Yes and today will be another below normal temp day! It has been a cold year so far!
GO GREEN!
MSU just played a GREAT game and took down the number one team in the tournament! What an incredible game and a phenomenal WIN!!!!!!!!!
We don’t get much significant hail around this area, but here’s a pic from last August I took. I posted it back then to, but this is probably the largest hail I’ve seen around here in many years.
http://tinypic.com/usermedia.php?uo=NuVqmzAy%2FKzKWtbuU10ANIh4l5k2TGxc#.XKEE_IwpChA
Barry will be saying it is a great spring day! Ya right! Feb temps and almost April! Incredible!
Well if you spent anytime doing hard work outside, you would know that the perfect time to drop trees and split wood is when it is dry out, no snow on the ground, and not 90 degrees and humid. So yes, it is a perfect Spring day for getting outdoor work done unlike recent years when temps are already near or into the 80s by now.
Nothing like doing yard work in the snow with wind chills around 20 degrees! Give me a break!
You obviously have no idea how strenuous taking trees down is. Yes it was the perfect temp today for doing that. Sun was out all afternoon here, and I have no idea where all the snow you’re talking about was because it wasn’t here.
I have taken plenty of trees down and cut plenty of fire wood. Give me temps in the mid to upper 50’s for outdoor work, not wind chills in the 20’s ! Wow!
Wow? There is no wind chill in the woods where I was working because any wind is blocked. The only thing wow would be our incredible run of days in a row with sun. Except I suppose by you where you’re still shoveling snow.
31* degrees out at thee YARDofBRICKS I believe that is 19* degrees below normal right now….March 30th …..INDY!
Nice spring day?
I’m looking outside what is that I see snow..INDY!
Bring it!
Back in the late 1950’s my dad’s sister lived in Kansas and my dad had just bought a new 1955 Ford. I was a blue and white two tone car. Back then all the roads were for the most part 2 lane roads and it seemed to take forever to get anywhere. The first night on that trip we stopped at Hannibal, MO Overnight there was a tremendous thunderstorm that woke us up. There was my mom, dad my sister and me. We could here the hail inside the room pounding the roof. As I remember my mom saying she… Read more »
Talking temps in the 30’s and wind chills outside for the end of March pretty cool for this time of year but a few will say it’s a beautiful warm spring day outside I guess fooled from the sunshine again…Bring on sunshine and 60’s thats what Spring is really about …Try to stay warm today MV’S best on this Sunday funday….INDY!
It is cloudy here now with a temperature of 28° and I should add it is also windy. The official low of 22 was the coldest low for March 31 since 1997. We will have to see how warm it gets today for the high. While not record setting it is none the less a cold end to March.
Slim
Furnace bills are still Crankin in the mail! INDY!