Grímsvötn

Southeast

Iceland's most frequently erupting volcano is entirely out of sight, buried under the Vatnajökull ice cap. Grímsvötn is a subglacial caldera roughly 8 kilometers across that has erupted around 70 times in recorded history, with eruptions typically separated by only a few years. The most recent major event was 2011, when an ash column reached roughly 20 kilometers up and disrupted European air travel. Beneath the ice, a geothermally heated lake periodically drains in sudden glacial outburst floods — jökulhlaups — sending enormous volumes of water across the southern sandur plains. The volcano is inaccessible to regular visitors. What you can appreciate from nearby is what it has shaped: the flat, black outwash plains south of Vatnajökull were largely built by Grímsvötn floods over centuries. Skaftafell, about an hour to the southwest, offers good perspective on this scale. Checking the Iceland Met Office (en.vedur.is) on any southeast Iceland trip is sensible — Grímsvötn can give little warning before erupting, and the sandur plains south of the glacier are dangerous during events.

Book & Explore

The links below are affiliate links. If you book through them we may earn a small commission at no extra cost to you — it helps keep this guide free. See our about page for how we keep recommendations independent.