The most precipitous realestate crashes in Canada in the past 30 years — Calgary during the 1980s oil bust and Toronto in the early 1990s recession — resulted in losses of 25 % to 28 % in the average price of a house.
On my Case - Shiller graphs, move the date slider all the way to the left and you'll see that no city boomed and busted more than L.A. during the savings and loan realestate bubble in the late 1980s and early 1990s.