roof nubs

While traveling in Tohoku, I noticed that most of the homes had these little "nubs" on their rooftops.

Some were in nice rows, while some were scattered here and there.

I looked around online, and it appears that these "nubs" are to stop the snow from sliding off in big chunks.

Homes in these areas also had ladders leading up to the rooftops.

I've seen people shoveling snow off of their rooftops on tv during the winter.

I love seeing snow, but the novelty would definitely fade if I had to shovel.

Do you have snow where you live? Do the homes have "nubs" on the roof to stop snow?