(Reuters) – A blizzard shut down Denver International Airport on Wednesday, canceling more than 1,000 flights after it temporarily knocked out power and made takeoffs and landings unsafe, airport officials said.

The storm, which hit the Denver area early on Wednesday, caused ripple effects in other parts of the country, as planes were forced to sit on tarmacs while awaiting clearance to depart for Denver.

“Denver International Airport has made the decision to close the airport until further notice,” the airport said on Twitter. “Passengers should not plan on coming to the airport until further notice.”

The closure came one day after a suspicious package was found at the airport’s main terminal, prompting a brief evacuation amid heightened security in response to deadly suicide bombings in Brussels.

Power was knocked out at the airport for more than an hour on Wednesday, briefly preventing crews from fueling and de-icing aircraft, airport spokesman Heath Montgomery said.

A total of 573 departing and 549 arriving flights had been canceled at the airport by about 1 p.m. MDT, according to flight tracking website FlightAware.com.

Other flights destined for Denver were delayed by more than five hours, the Federal Aviation Administration said.

Blowing and drifting snow prompted the closure of Interstate 70 just east of Denver to the Kansas state line, the Colorado Department of Transportation said on it website.

Stretches of Interstate 25, the main north-south highway through the state’s urban corridor, were also shut down from Colorado Springs to the Wyoming border due to the adverse weather conditions and multiple accidents, the department added.

Authorities discouraged driving throughout eastern Colorado.

“When tow trucks and fire trucks are getting stuck it’s bad,” the Colorado State Patrol said on its Twitter feed.

Separately, 118,000 customers in the Denver metropolitan area were without electricity due to damaged power lines from ice buildup, fallen trees and high winds, said Xcel Energy spokesman Mark Stutz.

The Denver metropolitan area was expected to see between 6 inches and 12 inches of snow on Wednesday, with the fierce storm moving across northern and northeastern Colorado, the National Weather Service said.

The weather system is expected to move on from the central Rocky Mountains to the upper Midwest as it heads toward New England, the weather service added.

(Reporting by Keith Coffman in Colorado Springs and Alex Dobuzinskis and Dan Whitcomb in Los Angeles; Editing by Peter Cooney and Sandra Maler)