I have changed the names. We were a party of 5 in total, part of a climbing club group visiting the Lake District for winter climbing and hiking. Of the group, I am the least experienced in winter conditions. I have only had one previous experience of mountaineering or alpinism and no formal training. We had discussed snowfall conditions the previous evening when discussing route selection. The guidebook warned of cornices above the gully, but the group consensus was that there had not been enough snowfall to create significant cornices. None of the group were aware of the Felltop Assessors Report and so based conditions assessment on snowfall history and met office forecasts. We reviewed our decision regarding route selection as we left the hut, but concluded that the conditions still suited our target route: Nethermost Gully of Lad Crag, Helvellyn. The approach is a couple of kilometres, and was relatively free of wind despite forecasts of strong winds. Our approach valley and the target route lay in the lee of the prevailing winds. However we observed that snow depth was much greater than we expected, and as we neared the route it became deeper still, requiring tiring post-holing to progress upwards. Below the approach slope, we reviewed our route. However due to very low cloudbase it was impossible to see very far up the route. We were able to identify the start of the route, so we decided to ascend to the point where the approach slope met the mouth of the gully to reassess conditions. At the mouth of the gully we decided to fit crampons, helmets and ice axes. I was the lowest of the group. Above me, in order, were Fred, Alice and John. I took off my backpack and anchored it with one of my ice axes. Due to inexperience I had to remove and refit my crampons, as they were not fitted correctly. I had just done so, and was about to attach the leashes of my ice axes when I heard 'Wumpf!' followed by Alice's shout of 'Shit!' I looked up and was hit by a wall of snow. I was thrown on my back headfirst down the slope and managed to flip myself around so that I was feet-first on my front. I tried to slow my descent but rapidly found myself stationary above the snow. Looking down I could see Alice sliding on her bum down the slope a few metres below me and Fred far below her. John was standing stationary just above me. I quickly discovered that my right wrist was painfully sprained. I checked with John who was unhurt and had two axes (one of mine and his own). My sack and other axe had disappeared. Alice confirmed that she was unhurt. Fred had descended further down the slope and joined Lisa, about 100m below us. John, Alice and myself traversed right (facing the slope) to move out of the debris line, and then John and Alice briefly ascended to see if they could find Alice's axes or my axe or rucksack. We were unable to find them, though found some bits and pieces from my rucksack, and did not want to spend too long in the debris fan due to risk of another avalanche. Instead we descended to Lisa and John, where we discovered that they had retrieved my backpack and one of Alice's ice axes. Overall we had lost 4 axes. Remarkably Fred was uninjured despite tumbling around 100m down the snow slope. Lisa was able to observe the whole event unfolding, and watched John's spectacular descent accompanied by my Osprey rucksack, the frame of which was snapped in the process. As we descended we reviewed our decision making process and John stopped to perform a snow pack test. A 12 inch deep block on the slope sheared easily, indicating unstable snow pack. My right wrist was severely sprained and developed extensive bleeding and bruising, however not requiring anything more than a check up and some physio to recover. Fred suffered some bruising and stiffness. The other two were unharmed. The front pointing teeth of one of my crampons pierced the top and back of my right calf, creating two shallow cuts surrounded by small bruises, as well as tearing numerous holes in my waterproof trousers and gaiters. I also found a single hole in the seat of my waterproof trousers. Two days later we ascended Striding Edge, which overlooks Lad Crag, and photographed a couple of very impressive cornices above Nethermost Gully. If we had seen them from the base of the route we would not have attempted the climb.