A rare phenomenon happened recently in a North Dakota town. We received a video from Rhonda Rustad out of Ray. What looks like the aftermath of a snowball fight was actually created by Mother Nature. The set up has to be precise for them to actually form that’s why they’re considered rare.
They’ve been called “snow bales”, “snow balls” and “snow donuts” but are commonly referred to as “snow rollers’. Even though they’re rare, it takes ingredients that are easier to find in the Plains states like North Dakota than anywhere else in the country. Think of it as a snow tumble weed.
First, we need a thin layer of loose snow…something that we can pack together. Then we need the temperature near freezing, so around 32 degrees. This allows for some melting of that snow which makes it a little stickier.
Next, underneath that thin later of snow there needs to be either a layer of ice or powered snow… something that top thin layer won’t stick to.
To get that rolling action, we need a strong wind but not too strong so it doesn’t blow the snow apart. This allows the snow to roll and form first balls then after a while, what look like rollers. Some can measure a few feet hight.
Another way snow rollers are formed is when snow rolls down a hill. Gravity would do the work that the wind would normally do. This is why many can be found at the bottoms of hills.