Thought the worst was here? Think again. On the heels of the current mortgage meltdown created by sub-prime loans, investment fund manager Whitney Tilson warns of a second crisis caused by Alt-A and option ARM loans that are due to reset in 2010 and beyond.

Tilson recently told CBS's "60 Minutes" that a second mortgage meltdown is inevitable given the non-sub-prime, but equally questionable, lending practices commonplace during the mortgage boom of 2005 to 2007.

Tilson predicts up to 70 percent of these risky low-doc, no-doc, no income/no asset and "teaser rate" loans will default. Read more about the implications of a second mortgage crisis in the "60 Minutes" story A Second Mortgage Disaster on the Horizon.