MADISON, Wis. -- Traffic was moving again on Interstate 39-90 in Dane and Rock counties on Thursday morning after hundreds of motorists were stranded in the snow after a massive snowstorm blew through the area.

READ: Stranded Motorists Spend Night On Interstate | SLIDESHOW: See Images Of I-90 Backup | VIDEO: State, County Officials Defend Response To Backup | VIDEO: Watch Early-Morning Report (5:30 A.M.) | VIDEO: Watch Early-Morning Report (5 A.M.) | VIDEO: Watch The Report | TALKBACK: Tell Your Story

About 2,000 motorists were stuck overnight when the storm delivered whiteout conditions and heavy snowfall. The storm dumped more than a foot of snow in some parts of the state on Wednesday. (For more information, read related story)

The incident began when some tractor-trailers lost traction and got stuck on a small hill on I-90 north during Wednesday's storm. State emergency management personnel said the problem developed around 1 p.m. and traffic was backed up into Rock County. This produced a major backlog of over 1,050 vehicles in the westbound lane. As conditions worsened, this left hundreds of motorists, headed in both directions, stranded for hours in a traffic backup. At one point, the traffic backup on I-90 stretched 17 miles, WISC-TV reported.

Gov. Jim Doyle called a state of emergency to have National Guard troops help them late Wednesday night. About 70 National Guard troops on snowmobiles and all-terrain vehicles were checking on the stranded motorists early Thursday morning. They delivered fuel, food, water and blankets to some of those stuck.

The Guard soldiers made three separate trips on four-wheel drive vehicles to run motorists 7,000 bottles of water and more than 400 ready-to-eat meals, officials said.

The Dane and Rock county sheriff's department activated as many deputies as possible to help. State Department of Natural Resources workers were also out on snowmobiles, WISC-TV reported.

Lt. Col. Tim Donovan, spokesman for the Wisconsin National Guard, said that only minor medical conditions were reported. Donovan went up in a National Guard helicopter on Thursday morning to get an aerial view of the situation.

Donovan said 15 Humvees and two 5-ton trucks were being used to assist motorists with water and fuel, and two helicopters were being readied in case they were needed for aerial searches or surveillance.

Hundreds of vehicles were apparently locked in the backup. Donovan said that around 11 p.m., a Blackhawk helicopter was in the air to survey the scene. He said that from the helicopter they counted 552 tractor-trailers and 295 passenger vehicles at a standstill in both lanes. At 4 a.m., the State Patrol said that 475 vehicles were backed up in the eastbound lane and 460 were tied up in the westbound lane, but authorities said that traffic flow has improved since then.

Authorities said their initial efforts were slow-going because stuck vehicles and semis were blocking lanes, making it difficult for snowplows and emergency crews to get through.

They said Thursday morning that there are still some lane blockages. At the 151 mile marker, a tanker and flatbed truck were blocking a lane. Several semis were stuck on an off-ramp at Highway 73 and 160 exit.

Donovan said that hundreds of other vehicles are slowly moving out of the backup on eastbound Interstate 90 south of Madison and westbound south of Janesville. He said that soldiers had to wake up the stranded motorists to get them moving in the morning.

The state of emergency that Doyle declared is in place for 30 days, WISC-TV reported.

Authorities said that accommodations for motorists have been set up at two area hotels to provide shelter for some of the victims. (For more information, read related story)

State Patrol Head Defends Official Response

Many motorists complained that they didn't receive offers of help from authorities for hours after they became stuck. Some also complained that they received little official information about what was going on.

At a Thursday morning news conference, State and county officials defended their handling of the backup. The head of the State Patrol said that he sees room for improvement in the agency's response to the backup. State Patrol Superintendent David Collins said that he will look for ways to improve how authorities communicated the situation to the public. He also said that the State Patrol didn't learn about the backup until about 4 p.m. Wednesday.

Speaking at the Wisconsin Emergency Operations Center on Thursday morning, Collins said that officials "sympathize" with the stranded motorists, but first-responders faced the most challenging weather conditions that he's seen in his 28 years in law enforcement. He called the effort a "success" because throughout it all, there were no major traffic crashes, injuries or major vehicle damage.

Besides the State Patrol, officials with the Wisconsin National Guard, Emergency Operations Management and Rock and Dane county sheriff's departments attended the news conference. All congratulated their emergency crews and said coordination and technology were instrumental in "getting the problem solved as quickly and as efficiently as possible," WISC-TV reported.

Although the Emergency Operations Center was activiated at about 8 p.m. on Wednesday, it wasn't until 10:15 p.m. that the governor officially declared a state emergency. Collins said that the situation just kept getting worse and everybody did the best they could under the conditions. He said the response wasn't flawless, but a success in his book. He said that between 10 p.m. to midnight, some vehicles started moving out of the way and small groups of vehicles started going forward.

He and others also said it was the "right decision" not to close the interstate ramps. Officials said that would have drawn critical resources away from the backup scene and put people onto state highways that were snow-covered and dangerous. The State Patrol also said last month's huge chain reaction traffic crash on the interstate outside of Madison in thick fog was "totally different" and happened in a "totally different area." Officials said they think there was no correlation between the two incidents.

Stay tuned to WISC-TV and Channel 3000 for continuing coverage.