Volcanic Eruption

Press Enter to show all options, press Tab go to next option

Part of what makes the Pacific Northwest so beautiful are the gorgeous mountains that can be seen throughout the area. Majestic and beautiful, it is easy to forget that some of those mountains are actually volcanoes and could potentially pose a threat to the areas around them.

 A volcano is a vent through which molten rock escapes to the earth’s surface. When pressure from gases within the molten rock becomes too great, an eruption occurs. Eruptions can be quiet, or they can be explosive. There may be lava flows, poisonous gases, flying rock and ash, or landslides and mudflows.

While volcanic ash does not pose immediate danger to most adults, the acidic gas and ash can cause lung damage to small infants, to older adults, and to those suffering from severe respiratory illnesses. Volcanic ash also can damage machinery, including engines and electrical equipment. Ash accumulations mixed with water become heavy and can collapse roofs.

Before a Volcanic Eruption
  • Add a pair of goggles and disposable breathing mask for each member of the family to your disaster supplies kit, and put in a spare air filter for each vehicle.
  • Stay away from active volcano sites.
  • Make evacuation plans; plan a main route out, and have a backup route in mind.
  • Be prepared for the hazards that can accompany volcanoes: mudflows and flash floods; landslides and rockfalls; earthquakes; ashfall and acid rain; and tsunamis.
During a Volcanic Eruption
  • Evacuate immediately from the volcano area to avoid flying debris, hot gases, lateral blast, and lava or debris flow. Follow the evacuation order issued by authorities.
  • Be aware of mudflows. The danger from a mudflow increases near stream channels and with prolonged heavy rains. Mudflows can move faster than you can walk or run. Look upstream before crossing a bridge, and do not cross the bridge if mudflow is approaching.
  • Avoid river valleys and low-lying areas.
  • Avoid areas downwind and river valleys downstream of the volcano.
  • If caught indoors and you are not in the path of a lava or debris flow:
    • Close all windows, doors, and dampers.
    • Put all machinery inside a garage or barn.
    • Bring animals and livestock into barns and sheds if possible, other enclosed shelters otherwise.
  • If trapped outdoors:
    • Seek shelter indoors.
    • If caught in a rockfall, roll into a ball to protect your head.
    • If caught near a stream, be alert for mudflows. Move up slope, especially if you hear the roar of a mudflow.
  • Protection from falling ash:
    • Wear long-sleeved shirts and long pants. Use goggles, and wear eyeglasses instead of contact lenses.
    • Use a dust mask or hold a damp cloth over your face to help with breathing.
    • Stay away from areas downwind from the volcano to avoid volcanic ash.
    • Stay indoors until the ash has settled unless there is a danger of the roof collapsing.
    • Close doors, windows, and all ventilation in the house (chimney vents, furnaces, air conditioners, fans, and other vents).
    • Clear heavy ash from flat or low-pitched roofs and rain gutters.
    • Avoid running car or truck engines. Driving can stir up volcanic ash that can clog engines, damage moving parts, and stall vehicles.
    • Avoid driving in heavy ash fall unless absolutely required. If you have to drive, keep speed down to 35 MPH or slower. If you have to change the engine’s air filter, pull into covered space.
After a Volcanic Eruption
  • Keep windows, doors and dampers closed until ashfall ends.
  • If possible, stay away from volcanic ashfall areas.




The Hazard-Specific Information section was created using information from the Federal Emergency Management Agency and American Red Cross.