A 65-year-old man was found dead late on Monday in the eastern county of Suceava, an official told state news agency Agerpres.
Parts of a motorway linking the capital Bucharest to Constanta and dozens of other roads were closed. More than 80 trains and 15 flights were cancelled, Romanian police said, and Romania's Black Sea ports were closed.
Record snowfall of 182 cm (72 inches) paralysed the northern Croatian town of Delnice and rescue services took several hours to evacuate residents in the nearby village of Mrzle Vodice. Temperatures hit a low of -20 degrees Celsius in Zavizan on the Velebit mountain.
Schools were closed in Bucharest and ten Romanian counties as well as across western and central Croatia.
The roofs of dozens of houses collapsed under the weight of snow in the Unsko-Sanski canton in north western Bosnia.
State-run RTCG TV reported that Montenegro's main Golubovci airport was closed for several hours overnight.
In Britain, parts of the east saw up to 10 cm of snow and the weather service said temperatures could fall towards -10 degrees Celsius in some rural areas.
Some schools closed on Tuesday and train services and some flights were cancelled. In London, snow covered some parts of Westminster and a blizzard briefly swept through the Canary Wharf financial district.
A rare snowstorm in Rome on Monday prompted Italian authorities to call in the army to help clear the streets.
As the storm moved south on Tuesday, Naples saw the most snow since 1956. It blanketed the beach and covered fishing boats in small city ports such as Santa Lucia and Mergellina.
With a snow-covered Mount Vesuvius providing the backdrop, the snow paralysed traffic and train services. Schools were closed in Naples and much of southern Italy.