Foot of snow in Denver causes flight cancellations

More than 100 flights were canceled at Denver International Airport early on Tuesday as a powerful storm system dropped snow over the Rocky Mountains, while tornadoes were reported from Texas to Nebraska, officials said.

A blizzard warning was issued for a large swath of northeastern Colorado and western Kansas, with a storm system that originated in Alaska forecast to drop up to 12 inches of snow on theDenver metropolitan area by midday Tuesday, according to the National Weather Service.

Several tornadoes were spotted over northern Texas, western Kansas and southern Nebraska overnight, according to weather forecasting site AccuWeather.

Denver International, one of the busiest U.S. airport hubs where more than 100 flights were canceled in and out, advised passengers to allow extra time to get through security.

The storm was heading east, where it could cause flooding later along the Gulf Coast, the National Weather Service said.