(Adds details on power outages in Pennsylvania and Northeast)
By Scott Malone and Victoria Cavaliere
BOSTON/NEW YORK, Feb 5 (Reuters) - The latest in a series of winter storms hit the United States on Wednesday, dropping wet, heavy snow in the Northeast states that disrupted travel and threatened supplies of salt needed to keep roads clear.
Over a million homes and businesses were without power in the Northeast on Wednesday following severe snow and ice storms overnight, according to local power companies.
The hardest-hit state was Pennsylvania with 849,000 customers without electricity at one point, according to the governor. By 8 p.m. local time (0100 GMT Thursday), that was reduced to just over 625,000 customers, said Cory Angell, a spokesman for the Pennsylvania Emergency Management Agency. Most of those were in Philadelphia and surrounding counties.
Throughout the United States, 2,893 flights were canceled on Wednesday, according to FlightAware.com, an online flight tracking site.
The weather hit airports in the Northeast particularly hard, with roughly half the departing flights canceled out of Newark Liberty International, LaGuardia Airport and Boston's Logan International, FlightAware said.
The governors of New York, New Jersey and Pennsylvania declared states of emergency. The governors of Massachusetts and Connecticut told some state employees not to report to work due to the treacherous weather.
Officials in New York and New Jersey warned they were starting to run short of the rock salt used by road crews to keep ice from building up on highways and local roads, the result of the season's repeated storms.
"We have a salt shortage for some parts of the state, primarily New York City and the Long Island area, because there have been so many storms this season already," New York Governor Andrew Cuomo told reporters on a conference call. "The state does have a significant amount of salt on hand. We'll be shipping that salt around the state."
Neighboring New Jersey reported a similar salt shortage.
"We've had so many storms, one after another, that it definitely has put a very significant demand on salt," said Joe Dee, a spokesman for the state Department of Transportation.
"Our supplies are dwindling," Dee added. "We have plenty for this storm. We're looking at some weekend storms and we have enough for that, but we're going to start to get low. We need some good weather and a chance to replenish our supplies."
As of Jan. 26, New Jersey spent $60 million on snow removal, putting it on pace to break the record of $62.5 million spent last year, Dee said.
New York City has spread some 346,000 tons of rock salt on its roads so far this year, almost the total for last winter, said Belinda Mager, a spokeswoman for the city Department of Sanitation. The city has spent $57.3 million on snow removal so far this winter, putting it on track to top last year's spending.
Most U.S. states and major cities do not try to set an upper limit on spending for snow removal but authorize agencies to spend what is necessary and count on legislatures to cover the cost.
"Before I became governor, I never saw winter in budgetary terms, but now I do," Massachusetts Governor Deval Patrick told local WBZ radio, adding that he was counting on lawmakers to fund the state's rising snow-removal and salt tab.
Some commercial suppliers have run out of rock salt.
"We're just continuing to get crushed by these storms. With major rock salt shortages, it's starting to get scary out there," said Anthony Scorzetti, a hardware and paint manager for Braen Supply in Wanaque, New Jersey. "I have people calling from all parts of the East Coast looking for it, and we just have nothing."
Bruce Small, 58, an aircraft mechanic from Milford, Connecticut, called the local road conditions "horrible."
"Everyone was skidding all over the place," he said, calling the wet, heavy snow storm "miserable, brutal."
More than 300 traffic accidents were reported on major roadways and side streets throughout the state, with one that was serious but with no fatalities, according to Connecticut State Police.
Tom Breier, general manager of Ice Melt Chicago, a supplier based in Lisle, Illinois, said he got a call from a New York supplier pleading for salt but could not help.
"Everybody's in the same boat. There aren't a lot of options," he said.
The weather is causing shipping problems, he said. A lot of the salt in the Chicago area comes from Louisiana and Texas on the Mississippi and the Illinois rivers on barges, but the Illinois River is frozen. The salt is arriving by truck, he said, which increases freight costs.
Chilly weather broke a record for Feb. 5 in Denver, Colorado, where the high temperature on Wednesday stayed below zero, at minus 1 Fahrenheit (minus 18 Celsius).
"This is likely the coldest air mass we'll see in Colorado for 2014," said Kyle Ferdin, a meteorologist with the National Weather Service in Boulder, Colorado. The overnight low in Denver was forecast to hit minus 11F (minus 24C), he said. (Additional reporting by Mary Wisniewski in Chicago, Edward Krudy and Scott DiSavino in New York, Richard Weizel in Connecticut, Colleen Jenkins in Winston-Salem, North Carolina, Eric M. Johnson in Seattle, Keith Coffman in Denver and Alex Dobuzinskis in Los Angeles; Editing by Ellen Wulfhorst, Chizu Nomiyama, Gunna Dickson, Sharon Bernstein and Lisa Shumaker)