It’s a familiar scene from cartoons, but does it actually happen in real life? Can you make a small snowball, roll it downhill and watch it appreciably grow in diameter?
If you allow for continuous pushing, it will certainly work. That is how snowmen are made. I am sure you could come up with the right conditions to make it work with only the initial push. You need a certain type of wet, heavy snow for it though. A ball of that stuff is like a magnet to itself and will not only pick up more snow but also leaves and twigs as well.
I can only get so large before it will break up under its own weight, however. A car-sized snowball is probably pushing the limits, depending on the characteristics of the snow in question. A house-sized one, a la cartoons, is out of the question.
I’ve never seen donuts like in that story, but large pinwheels form in warm snow on steep slopes.
We had a sledding hill in Alexandria, VA. In February of 1979, a freak snowstorm hit, delivering around 2 feet of snow to the area. My friends and I were the first to make it to the hill, but the snow was too deep and unpacked to ride a sled down. Even an inner tube would just sink in the undisturbed snow. Fueled by certain mind altering substances, we came up with the idea of rolling a large snowball down the hill to pack the snow down and to create a track.
The snowball rolled clumsily once or twice, then picked up speed and disappeared into the darkness. We got on the innertube and slid down the hill. Considering the distance I flew and the two broken bones suffered by my friends, I’d say the snowball ws car-sized.
This was the dumbest thing I have ever done, and it never occured to me what might happen before we hit the monster snowball.
Teamwork: A few harmless flakes working together can unleash an avalanche of destruction.
If you roll a snowball on grass, and the snow is too packed and the grass is too long, it will pull up the grass and the dirt and then your Dad will yell at you.
Learned that one the hard way.
I’ve seen those too. Not that large though.
I guess The Wheel, was not so much invented as it was discovered, then.
I tried this when I was a kid. I started with small snowballs but they did not have enough mass to plow their way through the snow. I made one about waist high (on a kid) and it made it all the way down the hill but rather than grow in size it broke apart half way down.
It was a step into manhood as it shattered that old cartoon myth.
Looks like we discovered snow tires at right about the same time.
I remember making massive self-rolling snowballs one year in a large, steeply-sloping field - starting with a hand-rolled ball about two feet in diameter, it would roll and pick up snow on its own, however, it only seemed to work when the snow was in a certain state - freshly fallen, but quite sticky and wet - not powdery.
Also, because the ball tended to roll about a single axis, it would make wheels, rather than balls - and these would tend to widen as they went - ending up a bit like a thick disc with a deep dimple in either face.
They always broke apart around about the six to eight foot diameter mark, or sooner if they toppled and started rolling off-axis.
Interesting. Thanks for the replies.