(Reuters) – Millions of commuters along the U.S. East Coast will face another round of heavy snow, ice and wind gusts on Wednesday when the fourth major snow storm this month strikes the region, closing schools, grounding flights and halting buses and trains.

The nor’easter storm is on track to dump up to a foot of snow and bring gusts of up to 50 miles per hour (80 kmph) to major cities such as New York, Philadelphia and Boston on Wednesday and into Thursday, the National Weather Service said.

“Significant amounts of snow, sleet and ice will make travel very hazardous or impossible,” the service said in an advisory for New Jersey.

More than 2,000 flights had already been canceled on Tuesday evening at the three major airports that serve New York. Airlines said they were waiving fees to change flights from and to the East Coast.

The storm forced schools across the region including those in Philadelphia and New York, the largest school district in the United States, to cancel classes on Wednesday.

“For everyone’s safety, because it could be such a big storm … we want to be ahead of it,” New York Mayor Bill de Blasio said on Tuesday.

Both Greyhound bus service and Amtrak passenger train service suspended or abbreviated routes for the day. Throughout the East Coast, local bus and train services that millions of people rely on to commute to and from work and school also canceled service on Wednesday.

Widespread power outages were also expected on Wednesday as heavy snow and ice along winds may topple trees and power lines, the service said.

The latest storm comes after storms on March 2, 7 and 12 left at least 9 people dead across the region and more than 2 million homes and businesses without power.

(Reporting by Brendan O’Brien in Milwaukee; Editing by Amrutha Gayathri)