DENVER -- A late winter storm is bringing snow and cold that canceled classes for several Colorado school districts and made for a slick drive in the mountains.

Portions of Interstate 70 have been closed and reopened twice Friday morning because of multiple accidents.

The Colorado State Patrol said most of the accidents were drivers going too fast for the conditions who spun out or hit the median. Most of the crashes have been small with no major injuries or fatalities reported.

"There have been a few injury accidents, but primarily it has been mostly spinouts and people getting stuck from going to fast," said trooper Mark Savage.

Savage said truckers in particular need to be careful chaining up their rigs. One driver told 7NEWS the conditions make it hard for truckers to find the edge of the road when pulling over and they end up putting on chains right next to speeding traffic.

"Just try to keep as close to the truck as you can," said Bruce Geske. "I would have pulled over more, but it's so hard to tell with all the snow here."

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7NEWS reporter Lance Hernandez reported seeing several accidents along I-70 near Morrison including an overturned vehicle. So far the Colorado State Patrol has not reported any fatalities due to accidents.

"The drive is definitely tricky," said Stacey Stegman of the Colorado Department of Transportation.

Stegman said CDOT has its full fleet of more than 70 plows out clearing roads.

"We were well prepared for this storm," Stegman said.

Further west, the National Weather Service issued winter storm warnings through 6 a.m. Saturday for cities including Crested Butte, Aspen and Vail, with up to 18 inches of snow possible before it's all over.

Pitkin County officials were reporting icy roads and poor visibility Friday morning in Snowmass Village and on Colorado 82, which links I-70 to Aspen.

Snow also fell along the Front Range on Friday. Denver planned to keep three overflow shelters for the homeless open through the weekend.