At least 204 flights were delayed Saturday morning at Denver International Airport, as snow and bitter cold brought by a polar vortex gripped the metro area.

Nearly half of the flights -- 101, as of 11:45 a.m. -- belonged to United, according to flight tracking service FlightAware.

Another 54 belonged to SkyWest and 33 to Southwest, while AeroMéxico, Air Canada, Alaska Airlines, American Airlines, Delta, Frontier, Jazz and Key Lime Air experienced a smaller number of delays. No cancellations have been reported so far.

Snow and ice began impacting ground transportation across Colorado late Friday, and the National Weather Service warns snow and ice will continue to make roadways slippery through Saturday afternoon.