The number of foreclosure filings in Montgomery County spiked 2,000 percent in the third quarter of this year compared with the same time last year, proving that even a county with the seventh-highest median household income in the nation is not immune to the fallout from the escalating subprime lending crisis.

The county reported 1,009 foreclosure filings — default notices, auction sale notices and bank repossessions — between July and September of this year, 20 times more than the 48 filings made during those same months last year, according to national data provider RealtyTrac.