In one of the worst hit areas, snowdrifts and avalanches blocked roads in hilly northern Montenegro, where about a meter (3 feet) of snow fell overnight, officials said.
Across the border in southwestern Serbia, heavy snowfall blocked roads to more than a dozen villages, with some left without electricity and schools being closed for rest of the week, officials said.
"We have got heavy machinery out and we are doing all we can," said local emergency official Samir Bakic. "The wind is making the effort more difficult."
At least nine deaths across the region have been blamed on the snow and deep freeze, with temperatures as low as -15 Celsius (5 degrees Fahrenheit).
Elsewhere in Serbia, officials said the snow was falling so fast that road crews were unable to even clear the central squares of some cities. In Belgrade, fresh snow left suburban areas stranded and caused traffic chaos in the city, where snow had begun to fall on Saturday.
The milder climates of Montenegro's capital, Podgorica, and the nation's Adriatic coast usually escape tough winter weather, but snow is blanketing Podgorica, too, closing its airport and cutting off electricity to the city and several coastal towns.
In Bosnia, some areas were left without electricity and with snow-covered roads.
Serbia's top emergency official apologized on Tuesday for failing to clear roads over the weekend, when hundreds of people were stranded in buses and cars. Predrag Maric said that "even emergency vehicles were blocked on the roads and that the only solution was military vehicles."
Meteorologists predicted the cold snap will last until the end of the week.
In Croatia, doctors issued warnings to the elderly and sick to stay indoors as local hospitals reported dozens of cases of broken limbs from falls on the ice and snow.
Jovana Gec contributed to this report from Serbia, and Aida Cerkez from Bosnia.