Snow Rollers on Mt. Roosevelt Road.

Last Updated by Heather Benson on

With a Winter Storm Watch covering the entire state of South Dakota in mid-April, it may feel like the winter of 2018 will never end.  And while the snow may have lost its luster for many of us, the weather in South Dakota still has a few surprises in store, like these "snow rollers".

Snow1.jpgDave Dringman

Spotted by Deadwood residents Dave and Pat Dringman while hiking near Mt. Roosevelt Road in the Black Hills, snow rollers are a relatively rare meteorological phenomenon.  Snow rollers are formed naturally as chunks of snow are blown along the ground, picking up materials along the way, much like a human would make a snowman.  They can be tiny or huge, with some of the largest documented reaching the size of large cars.

However, unlike man-made snowballs, snow rollers are more typically cylindrical in shape and often feature a hollow core, making them look like donuts.  These hollow cores develop when the inner layers, which are the first to form, are weaker and thinner than the outer layers.  As the roller makes it way down the mountain side, the inner layer blows away and leaves a "donut hole".

Snow3.jpgDave Dringman

According to Wikipedia, the following conditions are needed for snow rollers to form:

  • There must be a relatively thin surface layer of wet, loose snow, with a temperature near the melting point of ice.
  • Under this thin layer of wet snow there must be a substrate to which the thin surface layer of wet snow will not stick, such as ice or powder snow.
  • The wind must be strong enough to move the snow rollers, but not strong enough to blow them apart.
  • Alternatively, gravity can move the snow rollers as when a snowball, such as those that will fall from a tree or cliff, lands on a steep hill and begins to roll down the hill.

Because it takes near-perfect weather conditions to create snow rollers, they are exceedingly rare. On a recent hike near Mt. Roosevelt Road in the Black Hills, Dave Dringman and his wife Pat were fortunate enough to spot these snow rollers and shared their photos on Facebook. They shared that the largest snow roller was a little over 2 feet in diameter and the smallest about 1 foot.  The couple initially discovered the rollers on Monday but did not have a camera with them.  But when they went back Tuesday, the rollers were still frozen in place.  "They are very cool, I had never seen them before." Dave shared with SDPB. "I'm guessing that the air temperature and the consistency of the snow had to be perfect and then the wind got them started downhill. We feel lucky to have come across them." 

Snow2.jpgDave Dringman


sub food blog link image learning blog link living blog link news and information blog link science and technology blog link sports blog link image


Dr. Mikel Holland Gives An Overview Of The New Hemsley Center

Dr. Mikel Holland is the President and Chief Medical Officer of Avera's St. Mary. He discussed a general overview of...

South Dakota Technology Showcase

Tuesday, September 25 is the South Dakota Technology Showcase where some of the state’s top innovators are on hand...

Biomaterials Day

Tayler Hoekstra is a PhD Candidate and Graduate Research Assistant in the Biomedical Engineering Department and...

Jennifer Benning - Engineering Community Service

Dr. Jennifer Benning, Associate Professor in the Department of Civil and Environmental Engineering at South Dakota School of Mines and Technology. She is also a...

Advancements Towards A Treatment For Ebola

Eddie Sulivan, SAB Biotherapeutics president and CEO, joined Innovation to discuss the recent advancements made by...

Tech Radio

Privacy concerns highlighted on Techradio

Troubling privacy concerns, Apple updates, and some surprising Edge news on the Dec. 7th Techradio

Social media news & tech gift ideas on TechRadio

The panel of experts discuss the news of the day, address online privacy, and highlight some of their favorite gift...

Facebook in the news and news of Facebook, plus new Mac hardware and software

Amos, Joel, and John T join Kent in a rolling discussion of Facebook and junk news. Also Joel rolls out news on new Mac software and hardware.

October 19th Techradio

Kent and the panel discuss self driving cars, a proper security posture that includes - s l o w i n g d o w n - and...

Techradio 10/05/18

Lots of interesting tech happenings from the week.

NPR Science News