The Giant's Causeway is Northern Ireland's top tourist attraction
Freezing conditions have led to the closure of one of Northern Ireland's top tourist attractions.
The Giant's Causeway and Carrick-a-Rede rope bridge on the north Antrim coast have been closed because of treacherous road conditions.
A National Trust spokeswoman said the icy weather had made the north Antrim coast area "extremely dangerous".
The Met Office has warned about widespread ice and further sleet and snow showers in the north and west.
Freezing conditions led to thousands of people, mostly in the north and west, having problems with their water supply.
NI Water said it received nearly 14,000 calls from 27 December to 3 January 2010, but that they are all now back on supply.
At the peak of the calls, more than 200 staff worked day and night to repair over 50 burst watermains, isolate private bursts, deliver over 60,000 litres of bottled water to customers and tanker water to service reservoirs.
The company said that with more cold weather expected there was a danger of more burst pipes when the thaw arrives.
There was disruption to some businesses and schools as they returned after the holidays.
A number of schools were closed because of the burst pipes and heating problems and some have announced they will be closed again on Tuesday.
While all the main routes have been salted, rural areas were still badly affected by the ice.
As the icy conditions continue, the government announced it would make a second round of cold weather payments.
Social Development Minister Margaret Ritchie said on Monday that an additional £25 would be paid automatically to about 166,000 people on low incomes to help with heating costs.
Anyone in the agricultural industry who needs urgent help is being asked to contact the Roads Service.
Last month was the coldest December in almost 30 years according to readings taken at the Armagh Observatory.
The mean temperature was 1.5C, the coldest average measurement since 1981.
However, December was sunnier and drier than normal with 53.3 hours of sunshine, about 40% more than normal for the time of the year.
Precipitation was 40% less than the average, but snow fell on seven days, from December 18 to 23 and on December 30.
There was grass frost on 27 days in the month, with air frost on 16 days.
The average temperature for 2009, at 9.87C, was close to the average of 9.94C for the last 20 years.
2009 was the second wettest year since 1981 with rainfall about 10% higher than the average.
Armagh Observatory has been taking weather readings since 1795.