(CNN) -- Heavy snow has stranded motorists for nearly 20 hours on a major thoroughfare near Buffalo, New York, with emergency personnel working to get them out despite continued and concentrated precipitation.

Tractor-trailers and passenger cars are marooned on two nearby four-mile stretches of Interstate 90 -- one eastbound and the other westbound. While there was some movement by early Thursday evening, large portions of the road remain closed to new traffic and the highway authority said it had no estimate when the interstate would reopen.

Authorities have plows and all-terrain vehicles to clear the road and provide food, water and gas to those stuck on the road, even busing stranded motorists to a senior center-turned-shelter in suburban Cheektowaga.

"We're still using ATVs that have police officers or [firefighters] operating them, inspecting to see if anyone needs any services," said New York State Police Capt. Michael Nigrelli. "We are seeing progress now, [and we're] hoping in the next few hours to see some breakthroughs."

MORE