At least one person was killed and thousands of motorists left stranded on roads after a fierce winter storm hit Colorado and the Rocky Mountains in the United States on Wednesday, Reuters reported. The “bomb cyclone” unleashed hurricane-force winds and snowy, blizzard conditions, leading to the cancellation of more than 1,300 flights.

The blizzard unleashed a gust of wind measured at 156 km per hour, which would be equivalent to a Category 2 hurricane, in Colorado Springs, CNN reported.

Colorado Governor Jared Polis declared a state of emergency and said he had activated the state National Guard for search and rescue operations. The National Weather Service issued blizzard warnings for parts of Colorado, Wyoming, Nebraska, and North and South Dakota, and schools and businesses remained closed.

The Colorado State Patrol said one of its troopers, Corporal Daniel Groves, was hit by a car that spun out of control. The 52-year-old officer was on the scene of another accident in which a vehicle had slid off the road when he was struck. Groves later succumbed to his injuries at a medical centre.

The Denver Police Department said it had received 125 crash reports so far. “If you absolutely have to head out, please be cautious,” it said.

All six runways at Denver International Airport were closed due to the blizzard. An airport spokesperson said a total of 1,339 flights had been cancelled till Wednesday afternoon.

Officials in the state’s El Paso County said close to 1,100 motorists were stranded on Interstate 25 near Colorado Springs. “We are in full ‘saving lives’ mode,” said county spokesperson Ryan Parsell. “This isn’t your average Colorado storm.”

Drivers trying to get home were brought to a standstill by the blowing snow that reduced visibility to inches, The Gazette reported. El Paso County Commissioners Chairman Mark Waller signed an emergency declaration allowing the county to seek assistance from state and local governments to help rescue stranded motorists. Electricity to 1,30,000 commercial and residential establishments was cut off as well.

According to meteorologists, a “bomb cyclone” is a winter hurricane that forms when the barometric pressure drops 24 millibars in 24 hours. The storm in Colorado has dropped 33 millibars since Tuesday morning.

“They typically do get strong systems this time of the year in that part of the country, but this one is may be a notch stronger than what you typically see,” said meteorologist Marc Chenard of the weather service’s Weather Prediction Center in Maryland.

The storm is also expected to bring torrential rainfall to eastern Nebraska, Iowa, Wisconsin and Minnesota, which have already received large quantities of snow. According to the weather service, the storm system is expected to weaken by Thursday.