Family members say Laura Macintyre and Eilidh MacLeod haven't been heard from since the explosion.
Winter Warning For Walkers
Life-saving advice has been issued to walkers and climbers to help avoid tragedy on Scotland's mountains this winter.
Mountain rescue teams helped 608 people who got into difficulties in 2014, with 12 fatalities.
Safety experts said simple precautions, basic knowledge and appropriate equipment were the key to avoiding accident and injury in wild places.
Mark Diggins, from the sportscotland Avalanche Information Service, said: "Many thousands of enthusiasts enjoy the Scottish mountains every winter.
"However, the fast changing weather, with its snowfall, avalanche hazard, strong winds, and poor visibility requires us to be much more prepared when going into the mountains in the winter.
"Good clothing, navigational ability, appropriate equipment, movement skills on steep terrain, and use of ice axe and crampons are a necessary requirement for our enjoyment and safety.''
The Scottish Government said it will provide a total of £1.81 million towards mountain safety this year, including £312,000 annual grant funding for mountain rescue teams and £1,041,000 for the Sportscotland national outdoor training centre at Glenmore Lodge, near Aviemore.
Sport Minister Jamie Hepburn said: "Scotland's wild places can be at their most beautiful during the winter months, and we want people to be able to enjoy them right through the year.
"There's no doubt that the weather conditions make this more challenging, and while this challenge is part of the appeal for many, it must be treated with the utmost respect.
"Simple precautions and basic common sense can greatly reduce the risk of getting into trouble.''
Outdoor enthusiasts are urged to use avalanche and weather reports such as the sportscotland Avalanche Information Service at www.sais.gov.uk and the Met Office and Mountain Weather Information Service websites.
The families of two girls from the Western Isles missing after attending the concert in Manchester targeted in a terror attack have issued appeals on social media.
Crews were called to the former Royal Victoria Hospital site this afternoon.
John Bermingham was also accused of assault and a breach of a Sexual Offences Prevention Order.
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