Already in mid March this year, an earthquake swarm, volcanic tremor and deformation caused an alert, because it was believed that this was caused by rapid movement of magma under the volcano.
The last eruption of the volcano was in March 2000, and it is estimated that by now, a significantly larger volume of magma has since then accumulated beneath the volcano. This would mean that a new eruption should be expected to be larger than the last one. Hekla's eruptions normally begin with a powerful explosive phase, and could pose a significant hazard to anyone in close (less than 10 km) proximity during the onset of it. [less]

"Uncertainty level" was declared by Civil Protection as the lowest of 3 alert levels in case of natural hazards. [less]