* Cold snap hits Balkans, Poland and Slovakia
* Thousands of motorists stuck overnight in Hungary
* Some 12,000 in temporary shelters waiting for weather to calm
* At least two people killed by flooding and high winds (Adds comments by PM Orban, fresh details)
By Krisztina Than
BUDAPEST, March 15 (Reuters) - Hungary deployed tanks to reach thousands of motorists trapped in heavy snow on Friday in a sudden cold snap and high winds which also struck parts of the Balkans, Slovakia and Poland and have left at least four people dead.
Snow stranded people in cars, buses and trains through the night and conspired with strong winds to cut off dozens of towns and villages in Hungary. The situation was critical on the M1 motorway linking Budapest and Vienna where hundreds of cars and trucks got stranded in the snow, most of them for over 20 hours.
By 1730 GMT disaster units had rescued most people stranded in the snow, putting up 12,000 in temporary shelters until the weather improved, Prime Minister Viktor Orban told a news conference.
He said 155 people were still out on the roads waiting for help, including one transplant patient in an ambulance whose life was in danger.
“The situation is particularly difficult and serious on the M1 motorway near the town of Babolna where there is a wall of snow, spanning 12 km (7 miles) with some gaps, and due to the strong winds even the deployment of helicopters is difficult,” Orban said on his return from an EU meeting in Brussels.
A Reuters photographer travelling with a rescue convoy said high winds had caused snowdrifts on the motorway up to a metre (3 feet) high, with some cars totally buried.
Two people were killed in an accident on another Hungarian motorway on Thursday when dozens of cars collided. Tens of thousands of people were without power in the northeast of the country.
Government spokesman Andras Giro-Szasz got stranded in snow on a road overnight until a rescuer pulled his car out at 4.a.m, he told local Inforadio.
Many people took to Facebook to appeal for help.
The government said it had sent out tanks and other military vehicles with caterpillar tracks to reach otherwise inaccessible areas and to pull vehicles out of snow drifts.
The weekend’s premier league and second tier football fixtures were cancelled, with night-time temperatures expected to hit -5 to -15 degrees Celsius (23 to 5 Fahrenheit).
After a relatively mild winter for much of the region, almost 200,000 people in Hungary, Bulgaria and Slovakia were left shivering without electricity on Friday. Heavy rain hit parts of Serbia and Bosnia.
In Bulgaria, one woman was killed when scaffolding collapsed in high winds in the central town of Gabrovo, and a school was evacuated in the southern town of Krichim when wind tore off the roof.
To the south, in Kosovo, a 10-year-old girl drowned when a river burst its banks in heavy rain in the northern town of Skenderaj. Dozens of homes were flooded in the west of the country, a Reuters reporter said.
“The situation is alarming,” Klina municipality spokeswoman Samije Gjergjaj told Reuters. She said some 300 people were stranded by 3-metre high floodwater.
“There’s just one small boat evacuating these people,” said Gjergjaj. “We’re waiting for the state emergency services to help out.”
Heavy snow also paralysed parts of southeastern Poland, where police banned heavy lorries from entering the city of Rzeszow for fear they would get stuck.
In eastern Slovakia, snow stranded about 40 lorries on a highway in the High Tatras region. The army deployed hundreds of soldiers to help out and authorities appealed to people to avoid venturing out by car. (Additional reporting by Fatos Bytyci in Pristina, Chris Borowski in Warsaw, Sam Cage in Sofia, Martin Santa in Bratislava, Daria Sito-Sucic and Maja Zuvela in Sarajevo; Writing by Matt Robinson in Belgrade; Editing by Pravin Char)