Ever seen an hailstone like this?

[Andrea Griffa]

This hailstone fell down in COFFEYVILLE Texas in 1970.It could be intersting if someone was chasing that storm in that year and to know if the storm did produce tornadoes or it didn't..
It measured 15-16 cm of diameter....This is simply crazy... It looks like the hailstone of june 6 2003 in Nebraska...


http://www.meteograndine.com/record%20mondiali/03.09.1970%20-%20Coffeyville/foto%201%20chicco%20con%20uovo.jpg

[Shane Adams]

Actually it was Coffeyville, KS on September 3, 1970. This stone held the world record for years until 2003 or 2004, when someone finally found one of those giant stones that seem to fall in Nebraska every year.

[Andrew Khan]

You say that a hail stone fell in Nebraska as of, 2003-2004, and beat the size record of that HUGE KS hailstone?! How big could this record beating Nebraska hail stone have been? I would hate to have been chasing or walking around that day.....I wonder what speed it fell to the ground at? I also read somewhere as of 2-3 years ago, that there was a hailstone in NE that left craters in yars and lawns....

[Mark Farnik]

Andrew, the storm you are thinking of hit the Aurora, Nebraska area on the afternoon of June 22, 2003, causing unparalleled damage. And yes, the new U.S. record hailstone fell from this updraft from hell supercell. From the NCDC report on the event:
Record setting hail occurred on the north side of Aurora. Thunderstorms erupted during the evening in south-central Nebraska. One storm near Aurora produced very large hail. One stone measured by an NWS Storm Survey team was determined to be the largest sized stone to fall in the United States. It measured 7 inches in diameter and 18.75 inches in circumference. Many other large stones were noted on the northern side of Aurora.

This beat out the Coffeyville, Kansas hailstone by a considerable amount.
If a 100 mph uprdraft is required to produce baseball size hail , I won't even begin to speculate on how strong an updraft would have to be to produce volleyball size hail , which is what the Aurora supercell did.
Just imagine what would have happened if this cell, which formed about 4:30 in the afternoon, had formed 60 miles to the east over Omaha, during rush hour... it makes me shudder to think of what the outcome could have been. It would have been along the lines of the Tokyo hailstorm sequence in "The Day After Tomorrow". And that's a scary thought to contemplate.

[Jay Cazel]

If I recall, Jim Reed and John Davies were on that storm and took pictures of that hail stone.

[Mike Hollingshead]

I know Jon was on it. We talked with him north of there earlier in the day. We blasted nw to the early convection and he said he wasn't so sure that was going to be the day's best play and stayed put. He was very correct. We were very wrong. That was a long drive back to get on the Aurora storm late. It reminds me how important good forecasting is and how little various radar tools can do you when you aren't in the right area at or close to initiation. But for what it is worth what I've seen of the Aurora storm's structure it wasn't visually that great. I would have traded the Aurora storm for the storm south of it as that was the real treat. Both those supercells were huge and not moving. Sigh.

[Dave Ewoldt]

http://www.crh.noaa.gov/gid/Web_Stories/20..._megastorms.php (http://www.crh.noaa.gov/gid/Web_Stories/2003/weather/06-22/22June2003_megastorms.php)

[mikegeukes]

http://www.crh.noaa.gov/gid/Web_Stories/2003/weather/06-22/images/bigger_stone.png
http://www.crh.noaa.gov/gid/Web_Stories/2003/weather/06-22/images/giant_stone.png

Source: NWS Hastings
Mike

[John Diel]

I remember that day in Coffeyville well. I grew up there! My brother and I had my father's hard hats on and we were trying to catch some hailstones with our baseball gloves. Natural selection at work, I tell ya!

This hail stone actually fell on the roof of a local beer joint if I remember correctly. It was, however, quite a storm. We were picking up quite a few softball and grape fruit sized hailstones that day. This particular storm was what lead me to the addiction I now bear.

[Andrew Khan]

Natural Selection LOL, also Darwin awards.


Here are the pictures I remembered seeing.

http://www.crh.noaa.gov/gid/Web_Stories/2003/weather/06-22/images/impact_crater2.png




http://www.crh.noaa.gov/gid/Web_Stories/2003/weather/06-22/images/impact_crater1.png


I would say the updraft would have had to be like 170-180 MPH right? Wonder what speed they fell at?!

[Jayson Prentice]

I know I saw a couple posts wondering what speed a hailstone like that would fall at...

Well I may have the answer!

I'm just going to put all the math on here, just so if I make a mistake somebody can notice it. :?

Hailstone was 7 inches in diameter, that would make a 3.5 inch radius, that has to be put into cm for the equation so, radius = 8.89 cm.

So, terminal velocity of the hailstone would be: 59.63 meters/sec. Translate that to mph, 59.63 x ~2.24= 133.4 mph!

There ya have it, terminal velocity of a hailstone that size would be a lil' over 133 mph!

[Andrew Khan]

I know I saw a couple posts wondering what speed a hailstone like that would fall at...

Well I may have the answer!

I'm just going to put all the math on here, just so if I make a mistake somebody can notice it. :?

Hailstone was 7 inches in diameter, that would make a 3.5 inch radius, that has to be put into cm for the equation so, radius = 8.89 cm.

So, terminal velocity of the hailstone would be: 59.63 meters/sec. Translate that to mph, 59.63 x ~2.24= 133.4 mph!

There ya have it, terminal velocity of a hailstone that size would be a lil' over 133 mph!


Wow.....wouldn't that practically go through the roof of a car? I know if it hit you in the head, you'd probably die....

[Jayson Prentice]

If it didn't go through it, it would sure have the roof down a couple feet! I'm sure it could though, just like it can go straight through the roof of a house. And I'm sure it would kill ya if it landed on you, I've been hit with nickel sized hail and it gives ya a pretty good sting. And I believe there has been people killed with baseball sized hail, so this thing would take ya out easily!

All I can say is that a hailstone this big is a freak of nature! With an updraft that strong in a storm... Wow!!

[Mike Hollingshead]

For what it is worth those stones looke to have a lot of surface area. I'd probably rather get hit by one of those than a more rounded softball. I'm sure the updraft speed would probably be fairly similar between those and a good round softball. A more impressive stone in my mind might have been the ones fallling from the supercell in nw MO May 29 2004(or maybe it was the 24...both days had tornadic sups there). I believe they were 6 inch in diamter and much smoother/rounded.

[Andrew Khan]

I know I saw a couple posts wondering what speed a hailstone like that would fall at...

Well I may have the answer!

I'm just going to put all the math on here, just so if I make a mistake somebody can notice it. :?

Hailstone was 7 inches in diameter, that would make a 3.5 inch radius, that has to be put into cm for the equation so, radius = 8.89 cm.

So, terminal velocity of the hailstone would be: 59.63 meters/sec. Translate that to mph, 59.63 x ~2.24= 133.4 mph!

There ya have it, terminal velocity of a hailstone that size would be a lil' over 133 mph!

Also, added to this, you would need to take i nto consideration the downdrafts/RFD going against the hail...which could add more speed to it's decent.

[Chris Lott]

I read about the Aurora, Nebraska storm in a book I have. It stated that the tops on this particular storm reached 70,000 ft. and the 7 inch hail in the storm was referred to as "volleyball size" hail. It said it tore big chunks of ground up like it was nothing, and it also stated I believe, that this was a slow moving storm and it had quite a bit of flooding as well.

[John Diel]

I don't suppose anyone would know if you could get a cast of the hailstones in question?

I do several Severe Weather Safety classes every year and having something like that for the kids (or adults for that matter) would be great!

[Jayson Prentice]

I know I saw a couple posts wondering what speed a hailstone like that would fall at...

Well I may have the answer!

I'm just going to put all the math on here, just so if I make a mistake somebody can notice it. :?

Hailstone was 7 inches in diameter, that would make a 3.5 inch radius, that has to be put into cm for the equation so, radius = 8.89 cm.

So, terminal velocity of the hailstone would be: 59.63 meters/sec. Translate that to mph, 59.63 x ~2.24= 133.4 mph!

There ya have it, terminal velocity of a hailstone that size would be a lil' over 133 mph!

Also, added to this, you would need to take i nto consideration the downdrafts/RFD going against the hail...which could add more speed to it's decent.

Actually, you wouldn't. The formula used is the terminal velocity formula, so this is the fastest speed that a hailstone could reach at that size. Anything going that fast is going to hurt and damage something, especially when I'm sure that thing weighed a good amount. Would be interesting if anybody can pull up some radar of that cell.

[Mike Hollingshead]

The link Dave posted has a radar image of it. You can also download level II data from the ncdc site on it(if you have a viewer). Well I guess if they have it. It seems some of the better events radar data is often missing. The southern cell produced the most flooding as well as a killer tornado(Nebraska's first in like 10+ years or something....only to have another killer tornado in ne NE the very next day!.....crazy statistic).

John, that is a GREAT idea. That would be a great conversation piece I'd think. I'd buy one.

[Greg Campbell]

I know I saw a couple posts wondering what speed a hailstone like that would fall at...

Well I may have the answer!

I'm just going to put all the math on here, just so if I make a mistake somebody can notice it. :?

Hailstone was 7 inches in diameter, that would make a 3.5 inch radius, that has to be put into cm for the equation so, radius = 8.89 cm.

So, terminal velocity of the hailstone would be: 59.63 meters/sec. Translate that to mph, 59.63 x ~2.24= 133.4 mph!

There ya have it, terminal velocity of a hailstone that size would be a lil' over 133 mph!

Wait a minute! What equation?

Terminal velocity is a matter of weight vs. drag. If the hailstone was a fused conglomerate, is would be full of voids, making it lighter than a solid sphere of ice. Drag would be difficult to calculate for such a lumpy, irregular object, and would probably be higher than it's size indicates.

On the other hand, drag is roughly a 'speed squared' value. Even if the hailstone was extra rough and 30% air, it would still be falling at over 100MPH. (Just a wild assed guess ;) )

-Greg

[GPhillips]

Would be interesting if anybody can pull up some radar of that cell.
Below are links to the 0.5, 4.3, and 12.0 slides through the storm. The radar images are at 0003 UTC and Storm Data had the hailstone at 0005 UTC.

http://members.cox.net/geophi/0.5.jpg
http://members.cox.net/geophi/4.3.jpg
http://members.cox.net/geophi/12.0.jpg

[Jayson Prentice]

I guess I never really posted the equation that I used, its' listed in a meteorology textbook that I have and I'm assuming that this would be for roughly circular hailstones, so as you said with it being so 'lumpy' this is a pretty tough thing to figure out. We could probably just leave it at it was traveling pretty darn fast! lol... But, as the rough estimate it was probably somewhere around 120-130 mph..

The equation that is given is this: (Square root: 1/3p divided by k) x (Square root: r) With r being in cm, the answer is then given in meters/sec. The p and k values are not direcly stated, but it shows that that equation is equal to: 20 x (Square root: r). I'm sure there is a better explanation of values, etc somewhere that I just don't know about. I was simply doing my best to try to get a rough estimate out there of how fast this thing was likely traveling. Hope it helped...

[Andrew Khan]

I know I saw a couple posts wondering what speed a hailstone like that would fall at...

Well I may have the answer!

I'm just going to put all the math on here, just so if I make a mistake somebody can notice it. :?

Hailstone was 7 inches in diameter, that would make a 3.5 inch radius, that has to be put into cm for the equation so, radius = 8.89 cm.

So, terminal velocity of the hailstone would be: 59.63 meters/sec. Translate that to mph, 59.63 x ~2.24= 133.4 mph!

There ya have it, terminal velocity of a hailstone that size would be a lil' over 133 mph!

Also, added to this, you would need to take i nto consideration the downdrafts/RFD going against the hail...which could add more speed to it's decent.

Actually, you wouldn't. The formula used is the terminal velocity formula, so this is the fastest speed that a hailstone could reach at that size. Anything going that fast is going to hurt and damage something, especially when I'm sure that thing weighed a good amount. Would be interesting if anybody can pull up some radar of that cell.

Yes, but this is without any other external influencing on the hailstone itself, besides gravity. That said, there were likely to be some sort of strong RFD/downdrafts affecting the falling motion of the hail stone, so to accuratly get an approximate speed, you would need to incorporate this into as one of the factors.

[Robert Dewey]

Yeah, Andrew is right. Terminal velocity only factors in gravity as the main vector (it's usually calculated in a vaccuum). If you have other external components acting on the object with great force in the direction of the objects mean motion (typically "down"), the object can easily exceed terminal velocity.

For example, that hailstone in a downburst of 200MPH will exceed it's gravitational terminal velocity of 120MPH.

But in the Aurora case, if the downdraft winds weren't exceeding the terminal velocity of the actual hailstone, then the hailstone itself wasn't exceeding terminal velocity.

[Greg Campbell]

Yeah, Andrew is right. Terminal velocity only factors in gravity as the main vector (it's usually calculated in a vaccuum).

???
There is/can_be no 'TV' in a vacuum . If the moon were to loose all angular motion, its impact speed would be limited only by the time available to accelerate before it hit Earth.


If you have other external components acting on the object with great force in the direction of the objects mean motion (typically "down"), the object can easily exceed terminal velocity.

For example, that hailstone in a downburst of 200MPH will exceed it's gravitational terminal velocity of 120MPH.

But in the Aurora case, if the downdraft winds weren't exceeding the terminal velocity of the actual hailstone, then the hailstone itself wasn't exceeding terminal velocity.

I guess it depends on your point of perspective. Relative to the air, it will still be falling @ 130MPH. If embeded in a 100 MPH (Aurora?) downdraft, it will be moving at 230MPH towards to the ground. If the downdraft is 200, it will fall at 330.

As the downdraft nears earth, it will spread out and the winds will shift to a horizontal vector. The hailstone's vertical velocity will also slow, although any lateral motion will increase it's ground relative speed. 130 down + 100 sideways = 164 diagonal MPH. Ouch!!

[Jayson Prentice]

Yea, there are several factors that would change the speed that it was falling at, but this is a 'decent' estimate I would say. Without doing more research into it using that simple formula is likely to work pretty good...

[Greg Campbell]

Here's a neat way to estimate it.

From http://en.wikipedia.org/wiki/Terminal_velocity

Approximating terminal velocity is much more easily done than calculating the terminal velocity because of the difficulty in finding the value of Cd. One simple small scale method is to hang an object out a car window by a thin string. The terminal velocity of the object is the speed of the car when the object hangs at a 45° angle. This can be easily proven mathematically because it is when the atmospheric drag (in the horizontal direction) is equal to the force of gravity.

Mental image: Driving down the road at 100+MPH with a 10lb hailstone swinging from a fishing pole stuck out the window. When pulled over, tell the police you're doing a "very important science experiment." :D

[Jeff Snyder]

Terminal velocity only factors in gravity as the main vector (it's usually calculated in a vaccuum).

Gravity is a force... F = m*a, so A = F / m. So, an applied force acts to accelerate. In a vaccum, a hailstone (or anythign else) will accelerate indefinately assuming there aren't other forces acting against gravity. In a non-vacuum, such as the atmosphere, air acts as a drag force that acts opposite gravity. So, without friction or things like turbulent eddies (both of which would be absent in a vacuum), the hailstone would have no terminal velocity -- it would accelerate until something stopped it. The terminal velocity is, therefore, the speed at which the downward acceleration/force from gravity is balanced by friction/drag (which act opposite the motion, or act upwards in this case).

Terminal velocity formulae are very complex, particularly for irregularly-shaped objects like giant hailstones. I wouldn't try to be too precise in your numbers given that the formula used is an approximation.

[Robert Dewey]

Well... I guess I can take the worlds biggest idiot award now... :oops:

How could I have forgotten one of the worlds best known experiments? The feather and the bowling ball / brick / whatever-heavy-object-you-choose in a vacuum?

Anyway, I guess a downburst would act against the drag vector... Allowing the object to accelerate until it reaches the drag force / weight force equililbrium. Wouldn't that mean an increase in ground-relative speed?

If the downburst suddenly stopped, then the drag vector would increase, and the object would begin to deccelerate as the drag / weight force evens out.

[Chuck Vlcek]

Well, to drag this topic out further, why not make a cast of that stone, then a replica of the same shape and density, then drop it from an airplane over (or near) where the original stone fell and measure its fall speed or at least the force of its impact. The unknown would be the difference in vertical velocity of the air column it falls through (original vs replica) but it would at least be a start. I recall reading about research involving impact sensors measuring the kinetic energy of impacting hailstones.

An updraft can "support" a higher than theoretical weight of hailstone in two ways: 1) irregular shape increasing drag and 2) simply slowing the fall thru a hail growth zone from top to bottom, so that it continues to grow even while falling thru the updraft. After falling below the freezing level, it might then exit the updraft and get caught in a downdraft to minimize melting.

[Kiel Ortega]

Originally posted by John Diel
I don't suppose anyone would know if you could get a cast of the hailstones in question?

I do several Severe Weather Safety classes every year and having something like that for the kids (or adults for that matter) would be great!
Just FYI, Don Burgess (NSSL) has a cast of the Coffeyville storm

[John Diel]

Thanks Kiel, I appreciate that info!