Also wear thick padded clothing for body protection. Always check for mudflows when approaching a stream channel. A mudflow can move faster than anyone can run and even buildings may not stop one. ONLY as a last resort. Walls can be crushed by rocks and lava.
Roofs are subject to collapse, even from just the weight of ash and debris.
For a fast moving cloud of gas, ash, rock fragments that accompany an eruption you may have only a couple of choices. Either shelter in an underground emergency refuge or hold you breath and submerge yourself underwater in a river, a lake, or the sea. The danger may pass in 30 second or so. If you are within the fallout area of an eruption keep your activity to a minimum. Evacuate if necessary.