Lava flows are usually fairly slow moving streams of molten rock which pour from vents in the erupting volcano and can travel over many kilometers. The speed of lava flows depend on the viscosity of the lava being ejected, the angle of the slope, if it's a wide sheet of lava or if its traveling through a channel and how much lava is being produced from the vent. The dangers of a lava flow are not particularly high and most casualties are from people own curiosity either from moving too close or by becoming trapped by the slow moving lava and being boxed in.

Perhaps the most dangerous known volcanic forces are pyroclastic flows which are high density mixtures of dry hot rock fragments mixed with hot gases that travel from a...