The total number of homes with foreclosure filings jumped 27% in October from September, when they'd been at the lowest level since 2006. It was the biggest jump in monthly foreclosure filings since August 2007.

Compared to October last year, homes with foreclosure filings still decreased, but this nationwide decrease is covering up what is now happening in 28 states and Washington D.C., according to the Foreclosure Report by ATTOM Data Solutions. There, the inventory of homes with foreclosure filings is beginning to rise even on a year-over year basis. And in some states it soared year-over-year:

Colorado +64%

Georgia +22%

Pennsylvania +20%

Arizona +17%

Virginia +15%

Massachusetts +11%

New York +10%

When home prices rise for years, foreclosure filings become rare because defaulting homeowners can usually sell the home for more than they owe and pay off the mortgage. The problem arises when home prices fail to rise locally, and it balloons when home prices fall. We've seen that last time around. After bouncing along super low levels during Housing Bubble 1 through 2005, foreclosure filings skyrocketed during the housing crash starting in 2006. At first it was just an uptick that no one paid attention to. By 2008, it helped take down the financial system.