“We’re about to have a big problem,” said Morris A. Davis, a real estate expert at the University of Wisconsin. “Foreclosures were bad last year? It’s going to get worse.”

Economists refer to the current surge of foreclosures as the third wave, distinct from the initial spike when speculators gave up property because of plunging real estate prices, and the secondary shock, when borrowers’ introductory interest rates expired and were reset higher.

“We’re right in the middle of this third wave, and it’s intensifying,” said Mark Zandi, chief economist at Moody’s Economy.com. “That loss of jobs and loss of overtime hours and being forced from a full-time to part-time job is resulting in defaults. They’re coast to coast.”

Those sliding into foreclosure today are more likely to be modest borrowers whose loans fit their income than the consumers of exotically lenient mortgages that formerly typified the crisis.

Economy.com expects that 60 percent of the mortgage defaults this year will be set off primarily by unemployment, up from 29 percent last year.