BOSTON — Icy weather Wednesday morning snarled travel through parts of the northeastern United States, with state police in Massachusetts reporting that 55 cars were involved in a series of crashes outside Boston.

It was the start of a forecast whipsaw of weather over 48 hours, with temperatures around Boston expected to pass 50 degrees Fahrenheit before dropping back below freezing overnight, when a snowstorm is expected to begin.

“We’re forecasting at least 8 inches of snow,” National Weather Service meteorologist Bill Simpson said.

The ice, the result of an overnight rainstorm, probably caught commuters off-guard because earlier forecasts anticipated temperatures would rise above freezing before the snow begins, Simpson said.

The result was chaos on roads around Massachusetts, Connecticut and New Hampshire, with multiple collisions reported, including the series involving 55 cars around the Boston suburb of Wakefield, Massachusetts.

People were injured in 55-car crashes outside Boston but none seriously, the state police said on Twitter.

Photos from the Wakefield area showed cars spun at strange angles and entirely blocking the roadway, with emergency responders having trouble maintaining their footing on icy roads.

The Massachusetts State Police had not yet counted the total number of traffic collisions around the state, a dispatcher said.

The Massachusetts pileup is similar to one in Maine that happened two years ago near Etna, where more than 75 vehicles ran into each other, unable to stop because of the ice.

Wednesday’s precipitation in Maine is being blamed for several minor slide-offs.

“As of right now, the dispatcher told me that we have had only two minor collisions,” Bangor police Sgt. Tim Cotton said Wednesday morning in an email. “Nothing serious at all.”

Maine State Police also handled a few minor crashes, with “the usual slide-offs and minor property damage — four or five of them,” Cpl. Trevor Snow of the Maine State Police said Wednesday morning.

A tractor-trailer carrying potatoes that went into the median Tuesday night near Plymouth and rolled onto its side is slowing southbound traffic near mile marker 162 as work crews remove the cargo and the vehicle, Stephen McCausland, spokesman for the Maine Department of Public Safety, said in a news release.

“Workers will be offloading the cargo of bagged potatoes, and then the big rig will be removed,” McCausland said in the post. “It is expected to take several hours. Motorists are advised that slight delays are possible.”

Massachusetts Gov. Charlie Baker ordered a two-hour opening delay for state offices.

“Exercise extreme caution,” Baker said, “as driving is very difficult due to icy conditions.”