Edit: I read the comment you linked, the reason we have such similar language is because Swedes and Norwegians call it the same thing and I guess both of us were unsure if 'lemming year' is a widespread term :)
A much more likely and charitable interpretation of events is that 'lemming year' is an event that many people have experienced and the experience is sufficiently similar that you get accounts that sound the same.
I mean, if multiple people described christmas morning to me, my first thought wouldn't be that they're all in actuality the same person.
Yup, these things:
https://www.cat.com/en_US/products/new/equipment/motor-grade...
Now, maybe you're thinking of something else, but a road grader would definitely do that grizzly job.