Winter wonderlands can be home to the unexpected sight of snow chimneys, or fumaroles, puffing steam into the sky. Occurring in volcanic regions, fumaroles are openings in Earth’s surface, from which hot steam and volcanic gases are emitted.
Close relations of hot springs and gushing geysers, fumaroles require heat and a gas or water source to burst forth. Volcanic magma (molten rock) under Earth’s surface provides the heat and gases. When magma comes into contact with groundwater, the water boils and is released as steam.
These steaming vents in Earth’s surface always occur in regions with active volcanism. They work in a similar way to geysers: underground water meets magma and is heated until it boils and bursts through cracks in the rock, making its way to the surface. A fumarole has a smaller reserve of water so emits only steam.