DENVER -- A storm that brought the first heavy snow of autumn to a large portion of the Rockies and western plains prompted school closures and was blamed for dozens of accidents in Colorado and Nebraska.

The slow-moving storm has dumped more than 2 feet of snow on parts of the state. It's expected to be the strongest October snowstorm in Colorado in 12 years.

Heavy snow was blamed for a multicar pileup on U.S. Highway 6 in Denver, and the weather closed two northern Colorado highways near Wyoming. The interstates remained open, with some closures on mountain passes.

Many schools in Colorado and Nebraska were closed because of the storm, including Colorado State University in Fort Collins, which sent students home early in the afternoon.

Denver International Airport reported some delays and asked fliers to call first to avoid being stranded at the airport.

Up to 18 inches of snow was forecast in Denver and along the northern Colorado Front Range. As much as 4 feet was possible in the Colorado mountains.

The National Weather Service predicted significant snowfall for a wide area of the Wyoming, Nebraska and Colorado plains. The storm also brought snow to northern Utah's Wasatch Front.

In Denver, slick roads caused rush-hour fender-benders Wednesday morning. A Colorado Springs homeless shelter has decided to allow people who have been kicked out for breaking rules to return because of the inclement weather.

Meanwhile, wind was expected to be a concern on the flatlands.

"When we start getting those wind gusts on Thursday -- gusts up to 40 mph -- it's going to create some blowing and drifting snow and that's going to cause some problems," said Dan Deal, with the Weather Service.

The system kicked up heavy winds and dust Tuesday in Nevada, Arizona and California. Blowing dust was blamed for unhealthy air quality in the San Joaquin Valley in California.