More than 2,000 flights out of Denver were canceled over the weekend after the region was blanketed by heavy snowfall.

A spokeswoman for the airport confirmed the figure to The Associated Press, adding that nearly all flights out of the airport on Sunday, totaling around 1,300, were canceled.

The National Weather Service (NWS) has issued winter storm warnings for much of the state, including the Denver area, warning that “travel could be very difficult to impossible” due to snowfall totaling more than 2 feet in some areas.

“A significant late season winter storm near the Four Corners region will track slowly east/northeast across southeast Colorado late tonight and Sunday. This track will bring significant snowfall to much of northeast and north central Colorado, and likely result in difficult if not impossible travel through Sunday and Sunday night,” said the NWS.

Up to 24 inches of snow is expected in the Denver area by Sunday night.

The winter weather forced the shutdown of Interstate 25 in the state between the town of Wellington and Colorado’s border with Wyoming, where the state saw some of the heaviest snowfall, according to local news reports.

Moderate to heavy snow will become widespread along the I-25 Corridor this morning and into the foothills.

NWS Boulder (@NWSBoulder) March 14, 2021

Colorado officials said road closures are likely, and residents to avoid unnecessary trips, according to the AP.