Blocks from the lava flow occasionally set fire to vegetation.
On 6th June, a debris avalanche extended 800 m down the SW flank of Arenal.
On 12th May a lava flow descended northwest to an elevation of 780m.
1993 Eruption During the night of 28 August 1993 a previously unknown type of pyroclastic flow, generated during a partial cone collapse and outpouring of an active lava pool at Arenal.
1998 Eruptions Strong eruptions occurred at Arenal volcano on 5th May 1998, with 23 pyroclastic flows.