student is among nearly 40 britons who are currently missing in nepal in the aftermath of the devastating earthquake which has killed 4,000 people .
susannah ross , 20 , told friends she was going trekking last week but has not been heard from since friday and may be unable to contact her loved ones at home in britain .
a number of britons were climbing mount everest at the time of the quake , while others were staying in the capital kathmandu or trekking through rural areas .