Two mathematicians' visit to the desert sheds new light on avalanches.

As your cereal tumbled into your bowl this morning, were you daydreaming of sand dunes or snowy mountains? It wouldn't be surprising given the drab grey skies outside. But now you have another excuse: the cereal, sand and snow can all be examples of granular flows.

Jim McElwaine tells Plus how he combines his two loves - mathematics and mountaineering - in avalanche research.