A storm that toppled trees and caused scattered power outages in California is bringing blizzard conditions to parts of Colorado, where up to 50 cm of snow is expected in the mountains.
With forecasters predicting 15 to 30 cm, Denver Public Schools closed all schools and offices Tuesday.
Colorado's largest school district, Jeffco Public Schools, was among those cancelling classes.
Denver International Airport reported at least two dozen cancelled flights and warned travelers to be ready for delays as planes were de-iced.
Strong wind before the snow delayed flights up to 40 minutes Monday night and some arrivals were diverted to Colorado Springs.
Northern California was first to feel the lashing blasts of the storm yesterday, which spread to the Sacramento and San Joaquin valleys.