Plunging temperatures could cause mobile phones to cut out in a cold snap that will bring widespread snow and ice over the coming days.The Met Office warned that heavy hail and snow showers could cause severe disruption on Monday morning as the half-term holiday gets off to a shivery start, with widespread sub-zero temperatures.Mobile reception could be lost if icy winds dry air moisture on power cables and cause them to break, forecasters said.Two yellow weather warnings for snow and ice are in place for large swathes of the south west, north west, Wales, northern Ireland and Scotland from midnight until Monday lunchtime.It comes after a lost walker with badly frozen feet was rescued in blizzard conditions in a nine-hour operation in the Cairngorms on Sunday morning.The foreign 56-year-old was found by the Cairngorm Mountain Rescue Team suffering from hypothermia. He was taken to the rescue base but required no further treatment. There could be a some respite, however, with milder temperatures set to return mid-week. Speaking on Sunday, Met Office forecaster Rachael Adshead said winds would ease across the south of England and Wales, while at the same time showers would die out across central and eastern parts.”So what we’re left with is a good amount of clear skies and relatively light winds, particularly across southern parts of the UK and that will lead to a cold night,” she said.”We could see temperatures fall down as low as about minus 1C (30.2F) to minus 3C (26.6F) quite widely across the UK tonight,” she said.Parts of Scotland could see temperatures as low as minus 6C (21.2F), the forecaster added. The new week starts on a very cold note, with #ice and #snow, so allow some extra time for those Monday morning journeys #weatheraware pic.twitter.com/xcwJ4Tcqt9— Met Office (@metoffice) February 11, 2018 “Longer journey times by road, bus and train services are likely while some vehicles could become stranded.“Ice is likely to form on untreated pavements, cycle paths and roads leading to some injuries from slips and falls. Power cuts may occur and other services, such as mobile phones, may be affected.” A view across Lough Ross in Crossmaglen, Co. Armagh, on SundayCredit:Brian Lawless/PA Ms Adshead said Monday might feel slightly less cold than Sunday, with wintry showers expected in the north and west.Scotland, Northern Ireland and north-west England will see snow showers, while further south is more likely to see a mixture of rain, sleet and hail. The mercury is predicted to dip below freezing for many parts on Monday, with possible lows of minus 5C (23F) in Scotland and a widespread frost.More snow is also expected in western parts during the day.The Met Office said: “Heavy hail and snow showers will lead to ice and snow accumulating on many surfaces. Want the best of The Telegraph direct to your email and WhatsApp? Sign up to our free twice-daily Front Page newsletter and new audio briefings.