Over the weekend, a powerful storm swept across the Midwest, causing temperatures to plummet far below zero, and unleashed heavy snowfall on portions of the Northeast by Sunday. This led to numerous airport delays and hazardous road conditions, while the Pacific Northwest prepared for additional rainfall following days of flooding and mudslides.

The storm, which commenced on Saturday, delivered several inches of snow to the New York-New Jersey metropolitan area, marking the region’s first major snowfall of the season. Light snow was also reported across parts of New England. By Sunday night, the storm was predicted to lose strength, paving the way for frigid arctic conditions with windchill temperatures expected to dip below zero degrees Fahrenheit (-18 degrees Celsius).

In response, road crews and contractors were actively plowing and treating highways in New Jersey, where the state’s Department of Transportation urged residents to refrain from unnecessary travel. Meanwhile, in New York City, salt spreaders and plows operated throughout the night clearing snow from roads and bike lanes, according to updates from the city’s Department of Sanitation. Pennsylvania enforced temporary speed limits, reducing them to 45 mph (72 kph) on its interstates.

The severe weather resulted in the delay of over 1,000 flights and more than 100 cancellations at U.S. airports, as tracked by the flight monitoring website FlightAware.

In tandem with the storm, a blast of arctic air descended from Canada into sections of the northern United States. The National Weather Service in Chanhassen, Minnesota, reported that Sunday marked the coldest morning of the season so far. The Minneapolis-Saint Paul International Airport recorded temperatures of -10 degrees Fahrenheit (-23 degrees Celsius), with some local areas experiencing lows of -22 degrees Fahrenheit (-30 degrees Celsius).

In the Pacific Northwest, which has seen catastrophic flooding that has forced thousands of people to evacuate, more rain and wind was expected in the region as early as late Sunday, forecasters said.