A new technique will aid in predicting the dispersal and drift patterns of large floating ‘islands’ of pumice created by volcanic eruptions at sea. Known as pumice rafts, these large mobile accumulations of pumice fragments can spread to affect a considerable area of the ocean, damaging vessels and disrupting shipping routes for months or even years. The ability to predict where these rafts will end up could give enough advance warning for protective measures to be put in place on shipping routes or in harbours where the presence of pumice is hazardous....