Hi there...I've been searching the net and hoping someone can provide some insight. I live in Toronto Canada in a high rise condo. I have several mirrors in my unit: some are hanging from the wall (they are approx 20 lbs); one is leaning against the wall (6 ft high x 4 ft wide); one is a sliding door to a closet (full mirror); one is a piece of furniture (a night table covered with mirrors). I';ve had this condo since 2005. The closet mirror being there since it was built, and all other mirrors since 2009. Last month after a thunder and lightening storm I noticed 3 of my mirrors all had cracks in the them on the corners. All the affected mirrors are also beveled. Two days ago after returning from a week away, I noticed a forth mirror cracking. There was a lightening storm while I was on the airplane that lite up the sky. Today I found the closet mirror (completely flat) that slides side to side - cracked on the corner as well! My condo unit is next to a single elevator. I live across the street from a hydro station (sometimes when a transformer blows the unit shakes). The mirrors cracked all recently and I am trying to figure out why all of a sudden this is happening and how I can prevent further damage. Could it be due to the lightening storms?