The original photo, courtesy of the Tempe Historical Society, shows a 1931 flood along the Salt River. After finding the exact same spot as the original photo, geography major Richard Stumpf, superimposed the position of 2003 development along Town Lake. This manipulation provides the viewer a sense of the extent of past flooding.

Could this happen in the future? 

To answer this question, we look to the past.  This 1935 aerial photograph below shows the position of the Salt River up against Tempe Butte.  The curved shape of Lot 59 comes from the Salt River's persistant position next to Tempe Butte. The "natural" state of the Salt River has it undercutting and eroding Tempe Butte's north side.

The Army Corp of Engineers channelized the Salt River and built large levees.  Tempe Town lake exists inside those levees.  Is it possible that the Salt River will have such a large flood as to break out of its human-made channel?  The answer is yes.  But it would have to be a flood larger than what we've experienced in the past century.