Ankara, Jan 24 : Heavy snowfall across Turkey, including the main cities of Istanbul and Ankara, have disrupted flight services and road traffic, while meteorologists have warned that the cold spell could last until the end of next week. "Turkey is under the spell of a polar vortex, and we can expect temperatures to plummet to minus 14 degrees Celsius in some provinces. This episode is expected to last on and off for about two weeks," meteorologist Adil Tek told Xinhua news agency on Sunday. "This is one of the longest cold spells in the last decade," he explained. A total of 77 flights have been cancelled or delayed due to weather conditions from Istanbul's Sabiha Gokcen airport located in the Asian side of the city on Saturday and Sunday, flag carrier Turkish Airlines announced. Land traffic has also been disrupted in Istanbul. Up to 20 cm of snow has been recorded in some parts of the city, the Turkish State Meteorological Services announced. In Ankara, roads were covered with a thick blanket of snow, disrupting traffic despite the round-the-clock efforts of municipal rescue trucks and hundreds of workers. The country's eastern and southeastern provinces are also hit by severe snowfall in the last five days. A snowstorm particularly hit hard the city of Gaziantep, the heaviest in the last 50 years, according to local authorities, wreaking havoc. Diyarbakir, the main city of the region, has also been covered under snow, severely disrupting road travel. While there is a downside to heavy snowfall, it is also a blessing as the country is reeling from drought. The country's hydro dams will benefit from the snowfall after a dry spell, authorities said. /IANS