Heavy snowfall descended on large parts of Turkey on Tuesday, snarling road and air traffic and leading to closures of schools, reports said.

In the northern province of Karabuk, a school bus went off the road and turned over on to its side in slick conditions caused by snow, leaving a student dead and 18 others injured, the Dogan news agency reported.

The snowfall also seriously disrupted road traffic across Turkey and caused trouble with the electricity network causing some power cuts, particularly in the northern parts of the country.

Turkey's national flag-carrier Turkish Airlines cancelled 44 international and domestic flights in and out of Istanbul and some other cities including the capital Ankara.

In mega-city Istanbul, the authorities appeared to take every precaution including closing down schools. But the snow has so far failed to appear in the city in the quantities predicted.

Some ferries across the Bosphorus have been cancelled.

Schools have also been shut down in some parts of Ankara where the snowfall reached 15-20 centimetres (six-eight inches) in some areas.

Dozens of people were injured in accidents caused by poor weather conditions that caused traffic snarl-ups, media reports said. The snow led to the closure of the Istanbul-Izmir highway, with hundreds of cars being stuck on the road.

Authorities have been warning for days that the cold spell would be unprecedented, saying the temperatures might drop to as low as minus 20 degrees Celsius (minus four Fahrenheit) for Istanbul.