This was posted on February but got no attention until yesterday. While it may have been staged, I have no problem believing it — there have been many similar cases of rotten or fragile buildings falling under minimal vibration.
Most probably these guys were just walking by and noticed how the building was in a very precarious situation. And the weight of all that snow certainly helped.
Here's a good example of another building going down with some vibration in Ashton-under-Lyne, England:
And the newspapers are full of stories of similar accidental collapses, some for no apparent reasons. Here's one apparently caught in Russia at a wedding celebration (not a good omen).
Or this building in India. Or this one in the Philippines:
Got more? Post links to them in the comments.