Hekla had been dormant for at least 250 years when it erupted explosively in 1104 (probably in the autumn), covering over half of Iceland (55,000 km2) with 1.2 km3 / 2.5 km3 of rhyodacitic tephra. This was the second largest tephra eruption in the country in historical times with a VEI of 5. Farms upwind of the volcano in Þjórsárdalur valley (15 km away), Hrunamannaafréttur (50 km away) and Lake Hvítárvatn (70 km away) were abandoned because of the damage. The eruption caused Hekla to become famous throughout Europe.