(NEW YORK) -- At least two people have died in connection with an "extreme" lake-effect snowstorm in western New York that could dump up to 6 feet of snow in the Buffalo region.
Two Erie County residents died from cardiac arrest "related to exertion during shoveling/snow blowing," Erie County Executive Mark Poloncarz said Friday.
A state of emergency has been declared for Erie County, which includes Buffalo, as the potentially historic snowstorm hits the region.
A countywide driving ban went into effect Thursday night, with only those authorized for emergency travel allowed to drive. It was temporarily lifted in Buffalo Friday morning, before being reinstated for the city, Poloncarz announced.
South Buffalo in particular has been hit "incredibly hard," Buffalo Mayor Byron Brown said during a press briefing Friday, prompting officials to reimpose the travel ban.
"We do not want any driving in that area at all," Brown said.
A lake-effect snow warning is in effect through 1 a.m. Saturday for southern Erie County. A winter storm watch will be in effect from Saturday evening through Sunday afternoon.
At least 5 feet of snow is possible for parts of the region by Saturday morning, with snowfall rates of at least 3 inches per hour accompanied by lightning and gusty winds as high as 35 mph.
"This will produce near zero visibility, nearly impossible travel, damage to infrastructure, and paralyze the hardest-hit communities," the National Weather Service warned.
The long-duration event brought intense bands of lake-effect snow across Buffalo and Watertown Thursday night. On Friday, the lake-effect band off of Lake Erie is forecast to shift slightly north and remain over Buffalo and the Southtowns, while the band off of Lake Ontario will remain slightly north and over the Watertown metro area, according to the National Weather Service in Buffalo.
Parts of Erie County have already reported 4 feet of snow as of midday Friday. An additional 20 to 40 inches are likely between Dunkirk and Buffalo, for up to 6 feet of snow possible in some areas.
Region prepares for 'dangerous' conditions
New York Gov. Kathy Hochul issued a state of emergency in 11 counties due to the storm, with hazardous travel conditions and lower power outages likely.
"This is considered an extreme event," Hochul said during a press briefing Thursday morning. "That means it's dangerous. That also means it's life-threatening."
Hochul said that conditions in Buffalo and other parts of western New York will be "very similar to 2014," when the region saw upwards of 5 feet of snow during a deadly storm.
More than 350 plows, 5,700 utility crews and the National Guard have been deployed and are standing by, she said. Parts of the New York State Thruway also closed to commercial traffic starting at 4 p.m. Thursday.
"This can go on for a number of days," Hochul said. "The cleanup is going to take some time."
Schools in the region are preparing for closures on Friday due to the storm, including in Buffalo.
Erie County's executive advised private businesses to close on Friday if the forecast holds.
"We are gonna have a doozy," Poloncarz said during a press briefing on Wednesday.
The city of Buffalo has brought in private contractors to handle the snow in addition to state support, according to Mayor Brown.
"This is not the normal snow event that we get, so the public has to be patient," Brown told reporters. "This is a major snowstorm."
More than 100 plows were working at one point earlier Friday and more resources and private contractors will be brought in Saturday, city officials said.
Sunday's game between the Buffalo Bills and Cleveland Browns has been moved to Detroit due to the weather forecast, the NFL announced Thursday. The game was initially scheduled to be played at Highmark Stadium in Orchard Park, New York.
Lake-effect snow hitting several states
Lake-effect snow is common in the late fall and early winter along the downwind shores of the Great Lakes, which is caused by cold air flowing over the warmer waters of the Great Lakes.
In November 2014, more than 5 feet of lake-effect snow fell just east of Buffalo, in what was one of the most significant winter events in the city's history, according to the National Weather Service. There were 13 fatalities due to the storm. A second lake-effect event days later dropped another 1 to 4 feet of snow in the same area, bringing the total from the two storms to nearly 7 feet.
Beyond New York, lake-effect snow is forecast for several states, including Indiana, Michigan, Ohio and Pennsylvania.
Buchanan, Michigan, has reported at least 13 inches of snow, while Gile, Wisconsin, was hit with over 22 inches of lake-effect snow.
ABC News' Kenton Gewecke, Max Golembo, Victoria Arancio, Matt Foster and Brian Hartman contributed to this report.