UPDATED 01/12/11 11:44 a.m.

PORTAGE, Ind. (CBS) — The violent lake effect snowstorm prompted authorities to close not one, but two expressways in Northwest Indiana Wednesday morning.

The first closure was on the Indiana Toll Road (I-90.) All westbound traffic was shut off at the 26 mile marker, east of the Portage Toll Barrier, after a semi-trailer truck spun out, according to Indiana State Police.

By around 11 a.m., both lanes had been opened.

To the east, the tollway from Portage all the way to South Bend is also closed to truck traffic until 4 p.m., state police said.

Meanwhile, all westbound traffic on Interstate 94 was shut down at the 38 mile marker, just west of the U.S. 20/U.S. 35 exit. The area is experiencing whiteout conditions, and several cars have crashed and semis have jackknifed, state police said.

This is the second day in a row that snowstorms in Northwest Indiana have forced authorities to shut down roadways.

On Tuesday morning, southbound Interstate 65 was due to a crash involving a car and a semi-trailer truck. While the expressway later reopened, the snow led to several other crashes, particularly farther south in Boone County, Ind., where a semi jackknifed and many vehicles slid off the road. The expressway was closed again in both directions near Lebanon, Ind.

A lake effect snow warning is in effect for Porter County, Ind., until 4 p.m. Wednesday, and for LaPorte, Starke, St. Joseph and Marshall counties in Indiana, and Berrien County, Mich., until 6 a.m. Central Time Thursday.

A lake effect snow warning can mean snowfall so severe that travel can be hazardous or even impossible. Lake effect snow showers usually align themselves in bands, some of which might drop an inch of snow per hour for several hours, according to the National Weather Service.

CBS 2 Meteorologist Megan Glaros says in Porter County, 8 to 12 inches of accumulation are expected. In LaPorte County, the South Bend area, and Harbor Country in Michigan, totals could top out at 12 to 18 inches.

Watch & Listen LIVE