The A 18 Mountain Road, between Ramsey and the Creg Ny Baa has been opened but the Department of Infrastructure (DOI) has urged motorists to “drive to the prevailing conditions”.

A yellow weather warning for ice has been put in place until 10:00 GMT on Saturday, with higher ground and low lying spots sheltered from the wind particularly at risk.

The Tholt-Y-Will Road and the Ben-Y-Phott Road, which adjoin Mountain Road, remain closed.

The DOI said the Tholt-Y-Will Road would be reviewed on Saturday morning, while conditions on the Ben-Y-Phott Road would be reassessed on Monday morning as it remained “very snow and ice bound”.

It said following an assessment, the department had made a decision that further pre-treatment of the winter gritting routes “was not required” on Friday evening.

The Mountain Road was closed on Saturday evening ahead of forecasted snowfall throughout Sunday.

Ronaldsway Met Office said road surface temperatures over higher ground would remain close to freezing overnight in first thing in the morning, creating a continuing risk of ice.

On lower ground, road surface temperatures would drop after dusk with expected clear spells leading to a risk of ice on untreated surfaces that has become wet during the day, forecasters added.

An amber weather warning for ice had been in place until 12:00 GMT on Friday.On Thursday, the Isle of Man Constabulary said it had responded to 15 road traffic collisions within two days during the icy conditions.

The Isle of Man Airport said a number of Thursday evening’s flights were disrupted “due to severe ice and snow conditions on the runway”, which meant that aircraft had been unable to land.

Kelsey Peers, from Greater Manchester, was arrested after an off-duty police officer became suspicious of her during the afternoon sailing from Heysham on 12 July.

Douglas Courthouse was told she had been offered £300 to carry the drugs to the island.

Jailing the 24-year-old for three years and eight months, Deemster Graeme Cook said it was a “really sad case” but a “message needs to be sent”.

The court heard Peers, of Whitefield in Bury, had boarded the 14:15 GMT sailing between Lancashire and Douglas.

The concerns of the off duty officer, who was also a passenger on the sailing, were reported to the Isle of Man Constabulary and Peers was arrested at the Sea Terminal as she got off shortly before 19:00 GMT.

Peers, of Whitefield in Bury, asked to be taken to Noble’s Hospital after being searched by police.She was charged with importing a Class A drug to the island after the cocaine was recovered three days later.

Her defence advocate said Peers, who pleaded guilty to the charge and had no previous convictions, was a “young woman” who had made “a very terrible decision”.

While custody “punishes people”, it did not “resolve why people take the chances they do”, she added.

Deemster Cook said Peers was “clearly someone who is easily influenced”.

However, he said there was a sign at the Heysham ferry terminal that warned of the sentences that could be imposed on those who brought drugs to the island and she had taken the chance “not withstanding that”.

A road closure order for the A18 Mountain Road, which has been closed since Saturday night, has been extended until midnight on Friday.

Ronaldsway Met Office has upgraded a weather warning for ice, in place until 12:00 GMT on Friday, from yellow to amber.

Forecasters said “largely clear skies” meant there was a “significant risk of ice forming” anywhere as many roads had remined wet or damp throughout the day.

While the whole of the island was vulnerable to the conditions, sheltered low-lying spots in central, southern and western parts of the island were most at risk.

The Department of Infrastructure (DOI) said existing ice and snowfall the previous night had “hampered efforts” to reopen the Mountain Road and the adjoining Ben-Y-Phott and Tholt-Y-Will roads.While efforts were initially been concentrated on lower roads earlier, staff had later been redeployed to Snaefell, it added.

A yellow weather warning for snowfall issued on Wednesday had been extended from 06:00 until 14:00 GMT due to continuing wintry showers in parts of the island.

The Isle of Man Constabulary said main routes were “passable with care” but urged the public to “leave plenty of time” for journeys, and “drive to the conditions, leaving plenty of distance to vehicles in front”.

The Isle of Man Airport said that while it was operational, snow and icy conditions in the UK, particularly in Liverpool and Manchester posed a threat of disruption or delays.

The Isle of Man Post Office also warned that postal workers would only deliver items where it was “safe to do so” amid the icy conditions.