The swirling water mingles the falling house with other abandoned houses. Many of them cling together, but the violent spinning trims fragments from the growing particle. Perhaps in the deeper, calmer waters, this piece of snow can grow to be longer than a foot. For now it is only a centimeter. Bits of feces from small animals land on the growing particle and weigh it down. Sticky colonies of dead diatoms cling to the snow. The drifting particle gains downward momentum.