After a hiatus the volcano began erupting pyroclastic flows; these were mostly constrained by the topography and were erupted in various stages, intercalated by ash fall that extended to larger distances. Most of these pyroclastic flows accumulated in valleys radiating away from Huaynaputina, reaching distances of from the vents. Winds blew ash from the pyroclastic flows, and rain eroded freshly deposited pyroclastic deposits. Ash fall and pyroclastic flows alternated during this stage, probably caused by brief obstructions of the vent; at this time a lava dome formed within the second vent. A change in the composition of the erupted rocks occurred, with the "Dacite 1" geochemical suite being increasingly modified by the "Dacite 2" geochemical suite that became dominant during the third stage.