In ‘Avalanche’ a rod is lowered to the ground, team members staying in contact throughout. Normally the task is easy. However, with larger group sizes counter-intuitive behaviours appear, including the object’s ascending. A formal theory for the geometric element and other human behaviour effects gives insight into the behaviours. Each player has two balancing loops, one involved in lowering the object, the other ensuring contact. For more players these loops interact and these can allow intermittent dominance by reinforcing loops, causing the system to chase upwards towards an ever increasing goal. Analysis indicates that there is only a narrow region in which the system is able to move downwards. An analogy is drawn between the co-operative behaviour required in this system and Prisoners’ Dilemma situations. Sensitivity analysis gives further insight into the system’s modes and their causes. Reflections on the benefits of formal theory building close the paper.