In the path of a volcano

What are the hazards?
When we think of a volcano erupting, most of us think: lava! But in fact, volcanoes that produce lava, although awe-inspiring, are not as dangerous as the explosive kind, which shoot out ash and rock fragments.

There are several other potential hazards too, including acid rain, landslides, rockfalls and mudflows. The latter is not so surprising if you consider that hot ash or lava can melt snow at the volcano’s summit. The melted snow mixes with ash and soil to form a fast-flowing mixture that can power down stream channels. Rainfall can also erode recent volcanic deposits to produce mudflows.

Volcanic eruptions, which are associated with tectonic forces, are also sometimes accompanied – if you’re really unlucky – by earthquakes and even tsunamis.

Volcano safety tips
If you’re going to be in an area anywhere near a volcano, make sure you do the following:

Before arriving in the area, read up about nearby volcanoes. Find out whether they are likely to erupt, and, if so, what the associated hazards are likely to be.

If you’re travelling in a group, always make sure you have a designated place to meet in case you get separated, and an ‘outside’ phone number (i.e. one in another, non-disaster area) to call. (This is of course common sense when tavelling, volcano or no volcano.) As in any area or situation where there is a risk for natural disaster, it’s a good idea to listen to regular news broadcasts. Consider carrying a battery-operated radio, in case of electrical power outages.

If an eruption occurs:
If you have access to a radio or TV, listen to broadcasts and follow instructions given by authorities e.g. evacuation. If you haven’t been told to evacuate, or if this is no longer possible or advisable, then stay put and close all the windows, doors and air vents, and block gaps e.g. under doors. This is to protect you from ash fall.

If you find yourself stranded outdoors: seek shelter – if not inside a structure, then behind a barrier that can offer some protection. To protect yourself from ashfall, wear long-sleeved shirts and long trousers, and goggles to protect your eyes. Use a dust mask or hold a damp cloth over your face to help breathing.

Avoid areas downwind and downstream of the volcano, as well as river valleys and low-lying areas. If caught near a stream, be aware of mudflows. Move upslope, especially if you hear the roar of a mudflow. If you see the water level of a stream begin to rise, quickly move to high ground. If a mudflow is approaching or passes a bridge, stay away from the bridge.

If caught in a rockfall, roll into a ball to protect your head.

The effects of an eruption can be experienced many kilometers from a volcano. Mudflows and flash flooding, wildland fires, and even deadly hot ash flow can reach you even if you can’t see the volcano during an eruption. Trying to watch an erupting volcano up close is a deadly idea.

After the eruption
Even if the pyrotechnics seem to have abated, continue to listen to broadcasts, and stay indoors until the authorities advise otherwise. And, however tempting it might be, this isn’t a good moment to go sight-seeing. Even under normal (i.e. non-disaster) conditions, it is an act of unmitigated foolishness to venture close to an active volcano (and in the case of some of the more dangerous, even 10km is too close) without an experienced guide.

Stay away from volcanic ashfall areas. If you can’t avoid them, then continue to keep your skin and face covered to avoid skin and respiratory irritation. This is particularly important for anyone with a respiratory condition like asthma or bronchitis. Watch out for roofs laden with ashfall, as this is surprisingly heavy and can even cause buildings to collapse. It’s also best to avoid driving in heavy ashfall, as this can clog the engine.

- (Olivia Rose-Innes, EnviroHealth Expert, Health24, updated by Health24 January 2014)
Sources:
Safety tips adapted from the American Red Cross. What to do if a volcano erupts. 1998.