From my observations I noted how an increased water level resulting from a thaw builds up mud banks, which are then partially dispersed during clear cool nights when the water temperature drops. I then waited for an increase in the strength of the water current. This takes place in the early hours of the morning, when it is coolest, and particularly during full moon, in spite of the fact that the actual volume of the water is then apparently less, because of its contraction through cooling. I arranged for the timber to enter the water at the right moment, and in one single night 1600 cubic metres of timber were all brought down to a temporarily constructed pond in the valley.