Any Thoughts on the Likely Cause of this Noise & Vibration?

[Marc Boucher]

This is embarrassing.  It was the lug nuts.

A few weeks or so ago I put the winter tires on.
Did the job myself so there's no one else to blame.
I was doubly certain to torque the nuts correctly, and gave it a test drive 
after.
I've since google'd it and read up...the need to re-torque aluminum rims 
25-50miles after fitting...(aluminum, cold, shrinkage, etc..).
Done this so many times before...don't know what was different this time. 
Unless someone at the parking lot it was in liked the tires ...
Anyways, thank you all,
MC