After a monthlong deep freeze, a drive across region roads might feel like a journey atop Swiss cheese.

The extreme cold spell between mid-January and last week -- followed by above-normal temperatures and precipitation -- is the perfect breeding ground for potholes, the traditional springtime thud that is already rattling axles, region road officials say.

"Blame it on the wet winter with rain freezing inside the pavement cracks," said Ken Scheeringa, of the Indiana State Climate Office in Indianapolis. "With the sudden extreme temperature change, the trapped ice is thawing and leaving openings under the pavement."

There have been about 30 full freeze-thaw cycles in the region, which is typical.

However, more cycles than usual occurred in January and there were fewer than normal in February, Scheeringa said.

Steve Charnetzky, Portage streets superintendent, said he has five crews out daily and predicts the worst season in five years along the city's 160 miles of roads. He said drivers should expect more potholes to come.

"You haven't seen anything yet," he said. "They can break out in a matter of hours. I'm expecting over the next few weeks the roads are going to start blowing apart."

The worst location in Portage is Central Avenue on the bridge going over Willow Creek, he said. He predicts the "frost law" could be enacted locally, which requires trucks to carry half loads and take alternate routes to limit extra wear on the roads.

Joshua Bingham, Indiana Department of Transportation spokesman, said half of INDOT resources are now devoted to patching.

Potholes are being filled on U.S. 30 for a quick fix, and bidding began last week for a resurfacing and signage project between Interstate 65 and U.S. 41, Bingham said.

Jay Olsen, Crown Point's public works director, is expecting very few potholes since the city has about 13 miles of newly paved roads in its 100-mile system.

David Proud, Dyer's director of public works, said the town's 60 miles of roads are generally in bad shape.

"We've paved a few streets lately but not enough to keep ahead of the game," he said.

Mike Claffey, Illinois Department of Transportation spokesman, said he expects a typical year but predicts increased reports in the next few weeks for the 9,300 lane miles in northeast Illinois.

A trouble spot has been northbound Interstate 57 where it feeds into the Dan Ryan, and the northbound Bishop Ford ramp that feeds into southbound I-57, Claffey said. He expects the Dan Ryan to be in good shape. Crews typically patch asphalt before rush hour, he added.