At least 18 people have died in an avalanche on Mount Everest sparked by a powerful 7.8 magnitude earthquake in Nepal. The avalanche buried part of base camp, raising fears for the safety of hundreds of climbers who are in the area, said Gyanendra Shrestha from the Tourism Ministry in Kathmandu. A number of Britons are among those who have not been heard from since the quake.The identities of those who died in the avalanche have not yet been released. Scroll down for video . Avalanche: Terrifying avalanche pictured from basecamp on Mount Everest caused by the earthquake today . The avalanche was caused by a powerful 7.8 magnitude earthquake which struck Nepal and has claimed the lives of almost 1,000 people . Carsten Lillelund Pedersen hid behind these rocks when the avalanche caught up with him at basecamp . A dining tent at basecamp has been turned into hospital. People are being treated for head injuries and fractures . Among those listed on Google Person Finder is Sebastian Lovera, a 22-year-old qualified skiing and diving instructor, from Tonbridge, Kent. His last known location was Khumjung on Tuesday, from where he was heading towards Everest Base Camp. His step-father, Greg Smye-Rumsby, said: 'Sebastian is an extremely lively and self-motivating person and that is why he went to Napal. 'We haven't heard from him. He would not have switched his phone off. We have tried ringing it. Sometimes it rings and sometimes we get an answer but it's an automated answer. It says the phone is switched off. He's certainly not a person to take risks. He's the absolute opposite.' Another Briton feared missing is Laura Wood, 23, from Huddersfield, West Yorkshire. She is described by a friend as a 'glowing lovely beautiful young girl often dressed in hippy type clothing'. Miss Wood, who has a strong northern accent, has been trekking in the Himalayas without any means of making contact. Officials today confirmed that at least 1,341 people have died as rescue teams continue to search for survivors who are feared to be trapped under rubble. The death toll is expected to rise. Carsten Lillelund Pedersen pictured after the avalanche . Tweeting from the mountain, Daniel Mazur from Bristol wrote: 'A massive earthquake just hit Everest. Basecamp has been severely damaged. Our team is caught in camp 1. Please pray for everyone.' Briton Chris Harling, from Cumbria, who is leader of the Adventure Peaks Everest North Ridge 2015 Expedition was also on the mountain when the avalanche struck. Posting on Facebook, he wrote: 'Here in base camp we initially felt minor tremmors, then the ground began to feel like jelly as waves passed through the rocks beneath our feet. 'Climbers appeared from tents all over camp to try to start to comprehend what they were feeling. 'As the movement became more violent I expected the loose and precarious rocky slopes above the camp area . to start shedding huge boulders - it was extremely alarming wondering if we were to be buried by rockfall. 'Sure enough, an area of steep cliffs did break off sending car sized boulders hurtling down only a few hundred metres from our tents. We are still feeling aftershocks hours later. He added: 'Our thoughts are with any local staff working on Everest who may have been affected by losses in today's quake.' Climber Alex Gavan from Romania tweeted: 'Everest basecamp huge earthquake then huge avalanche from Pumori. Running for life from my tent. Unhurt. Many, many people up the mountain. 'Huge disaster. Helped searched and rescued victims through huge debris area. Many dead. Much more badly injured. More to die if not heli asap.' A senior mountaineering guide, Ang Tshering, of the Nepal Mountaineering Association, said the avalanche occurred between the Khumbu Icefall, a rugged area of collapsed ice and snow, and the basecamp where most climbing expeditions have their main camps. A mountaineer reports from basecamp on Mount Everest following the avalanche which was caused by a quake . Carsten Lillelund Pedersen, a Dane who is climbing Everest with Belgian climber Jelle Veyt, said on his Facebook page that they were at Khumbu Icefall when the earthquake hit. He wrote: 'The earthquake near Everest was very strong and we could feel the earth shaking a lot, and then a huge avalanche swept over basecamp and Jelle and I had to run for our life, but I did not reach the tents and I had to hide behind the the stone puja. 'I could not see anything and it was hard to breath. 'Our camp is at the end of basecamp which is like a small city with almost 500 tents, I am sure there are casualties, and we fear for an Indian group we met that were heading up the ice fall.' He said  the injured, including one person with many broken bones, had begun to arrive. 'He was blown away by the avalanche and broke both legs,' Mr Lillelund Pedersen said. 'For the camps closer to where the avalanche hit, our Sherpas believe that a lot of people may have been buried in their tents. 'There is now a steady flow of people fleeing basecamp in hope of more security further down the mountain.' Everest basecamp: At least 18 people have died and many have been injured in the avalanche . Norwegian climber Teodor Glomnes Johansen, who was at basecamp, told a newspaper in Norway they are working to save lives. 'We carry out severely injured people. This is pretty tough and heavy. We do not know whether there will be more avalanches,' Mr Glomnes Johansen told Norway's VG newspaper. 'All those who are unharmed organise help with the rescue efforts. Men, women and Sherpas are working side-by-side. The job right now is to assist the doctors in the camp here.' Chinese media has reported that a Chinese climber and two Sherpa guides were among the dead. Climber Robin Trygg told Swedish news agency TT his Sherpa guides had been in radio contact with other guides on Everest and they reported an avalanche there hitting as many as 80 people. 'We were sitting in the tent and drinking tea when the earth, all of a sudden, began shaking. We didn't understand what happened,' he told the news agency. The United States Geological Survey said the quake struck 81 kilometres (50 miles) northwest of Kathmandu at 06.11 GMT, with walls crumbling and families racing outside of their homes . A senior mountaineering guide, Ang Tshering, said an avalanche swept the face of Everest after the earthquake . The avalanche is believed to have occurred between the Khumbu Icefall, a rugged area of collapsed ice and snow, and basecamp . Ministry officials estimated that at least 1,000 climbers, including about 400 foreigners, had been at basecamp or on Everest when the earthquake struck. April is one of the most popular times to scale Everest, before rain and clouds cloak the peak at the end of May. Mohan Krishna Sapkota, joint secretary in the Nepalese tourism ministry, said the government was struggling to assess the damage on Everest because of poor phone coverage. 'The trekkers are scattered all around the basecamp and some had even trekked further up,' Sapkota said. 'It is almost impossible to get in touch with anyone.' Choti Sherpa, who works at the Everest Summiteers Association, said she had been unable to call her family and colleagues on the mountain. 'Everyone is trying to contact each other, but we can't,' she said. 'We are all very worried.' Google has launched a 'person finder' website to help people reconnect with friends and loved ones in the aftermath of the earthquake. If you are searching for someone or have information about a person's whereabouts, you can visit www.google.org/personfinder/2015-nepal-earthquake. Mount Everest basecamp in Nepal pictured on April 11 before the avalanche hit, killing at least 18 people . Locals rescue a dust-covered man from the the rubble of a destroyed building, as they work to find and rescue any survivors of the disaster . Nepalese rescue teams remove a body from the rubble of the historic 19th century Darahara Tower in Kathmandu which collapsed in the quake . Homes, businesses and landmarks were destroyed when the severe earthquake  struck Kathmandu and the densely-populated surrounding areas at noon local time, officials said. Rescue teams continue to search for survivors who are feared to be trapped under the rubble. Home Ministry official Laxmi Dhakal warned the death toll is almost certain to rise. Effects of the quake were felt hundreds of miles away in neighbouring countries with 36 killed in India, 12 in Tibet and 4 in Bangladesh. Two Chinese citizens died at the Nepal-China border. In a statement from the Foreign and Commonweath Office, Foreign Secretary Philip Hammond said: 'My thoughts are with the people of Nepal and everyone affected by the terrible loss of life and widespread damage caused by the earthquake. 'We are in close contact with the Nepalese government. The British Embassy in Nepal is offering our assistance to the authorities and is providing consular assistance to British Nationals.'
Powerful 7.8 magnitude earthquake caused an avalanche on Mount Everest . At least 18 people have died and more than 30 injured on the mountain . There are reports the avalanche has buried people in tents at base camp . The earthquake - Nepal's worst in 81 years - has  killed at more than 1,300 .