Lava flows descended to 800 m down the volcano's north and northeast flanks.
Tourists and park rangers 2 km away on the western side of the volcano were evacuated.
An avalanche on 10th June produced an ash plume, and resulted in evacuations near the volcano.
Stage 1 eruptions from 1968–1971 were from a closed system.
Stage 2 eruptions from 1971–current were produced from an open system. Pyroclastic flows since 1986 have been associated with moderate column collapse from Strombolian explosions, and small block avalanches from active lava fronts.
2007 Eruptions Arenal volcano continued to be active in 2007 with Strombolian eruptions, lava flows and avalanches.
On 18th September 2007 multiple pyroclastic flows travelled 1km south of the volcano.
2010 Eruptions Eruptions continue at Arenal volcano in 2010. 2009 Eruptions During 2009 activity at Arenal volcano consisted of Strombolian eruptions, avalanches, and lava flows.
During February eruptions occurred at crater C with gas emission, strombolian eruptions, and avalanches. In mid June the hazard level was raised to Level 3 (on an increasing scale of 1-4), due to increased gas emission.
1988 Eruptions and Fatality A tourist was killed by ballistics while standing in the danger zone near Arenal's crater on 6th July 1988.
1968 Eruption Cows were seen by farmers moving down from the middle upper slopes of the volcano 2 weeks prior to the eruption.
A Costa Rican tour guide and two tourists were overrun by a pyroclastic flow on 23rd August.