Sue Drinker (Member 58,087) grew up in New England, the north-eastern region of the US, where ‘dense forests filter the sky and weather’, and she says, ‘It's like living in a broom closet.’ But Sue spotted this mighty storm cloud in the west – in Carbondale, Colorado. Here, ‘the sky reigns, and the shifting moods of each day parade across the horizon in endless vistas of elegance in drama’.

Sue’s storm cloud is a Cumulonimbus capillatus incus unleashing a microburst below as it begins to dissipate above. Microbursts are columns of rapidly sinking air that plummet from Cumulonimbus storm clouds. When the air is filled with precipitation, it can fall with extreme force. Microbursts occur when the air in the cloud cools rapidly. This can happen if some of the moisture within it evaporates or falling ice crystals melt, since both of these phase changes remove heat from the surrounding air. When the temperature in the cloud starts to drop, the inner column of air becomes denser and can bring the precipitation down with extra vigour.

In the west, Sue reflects, ‘Clouds rule – both with their presence and in their absence.’