First things first—you’re probably not going to get killed by a volcano.

Sure, the U.S. has 169 active volcanoes within its borders, making it one of the most volcano-rich countries in the world (it’s surpassed only by Japan and Indonesia). And sure, one of those volcanoes is widely thought to be the most active volcano on Earth.

But volcano deaths in the U.S. are thankfully rare. Only 90 people here been killed by volcanic activity since 1980, and 57 of those people were killed in the infamous eruption of Mount St. Helens that year. Most of the remaining deaths were of tourists who fell into superheated pools or breathed toxic gas in Yellowstone or Hawaii. So while volcanoes erupt every year in the U.S., they mostly do so without killing anyone.

Mostly. And so far. But if you’re anything like me, the ongoing eruption at Leilani Estates has piqued your curiosity about our nation’s fire-spewing death mountains. So you’ll appreciate this (relatively) short volcanic eruption survival guide.

Here’s what I’ll go over:

1. How we see eruptions coming
2. How to be ready for an eruption
3. How people die in eruptions (and how to not be one of them)

1. How we see them coming

In the U.S., our active volcanoes are monitored by scientists through the USGS Volcano Hazards Program. This program has placed a whole host of instruments on our country’s volcanoes; its scientists are able to observe their activity from remote offices thanks to gas detectors, seismic activity monitors, thermal satellite imagery, live camera feeds, and more.

These scientists also visit the mountains in person to look for deformation in the landscape, new gas vents, or other signs of activity. With this information, they’re not only able to anticipate eruptions but are also able to map which areas are at risk from lava flows, mudlslides, and other hazards.

In short, they’re on it.

The folks at the USGS have several different systems for coding volcanic activity, and they report updates on activity on their website and to all relevant authorities. You can sign up for those updates, but as a general civilian you’re most likely to hear volcano status updates when they come through the emergency broadcast system.

Those updates are tiered like this:

• Volcano Advisory: The volcano is more active than normal, but is not erupting. People in the area are advised to be aware.
• Volcano Watch: The volcano’s activity is continuing to escalate toward eruption, OR the volcano is erupting but does not pose a risk to people in the area.
• Volcano Warning: The volcano is either about to erupt or is erupting, and the eruption is or will be dangerous.

This is not news for those people who have lived near volcanoes for a long time. But if you’ve just moved to a volcanic area (Hawaii, southern Alaska, or the Pacific Northwest) or are planning to visit one, it’s important news for you.

2. How to be ready

Being ready for a volcanic eruption really entails two things: knowing what impact an eruption will have on your area and being ready to leave if you need to.

If you live near an active volcano, you should consult the USGS hazard assessments about it. They can get pretty technical in places, but these reports will give you a good idea of what the eruption risk is like in your area and how the area is likely to be affected by pyroclastic flows, ash, mudslides, and other hazards. Those publications can be found here.

With the information you learn from your local USGS reports and info from your local fire department, craft an emergency evacuation plan for your family. Identify preferred escape routes and meetup points that will minimize your exposure to lava flows or mudslides. Make sure everyone in your family knows at least the basic elements of this plan.

Keep a bag packed with supplies for this worst-case scenario. Store it in your basement, your car, or near your front door, and fill it with:

• Non-perishable food and bottled water
• A first-aid kid (we recommend My Medic’s MyFAK)
• A power system (batteries, a solar charger, or both)
• A powerful flashlight
• A communication system (like a satellite phone, PLB, or goTenna device)
• Goggles and breathing masks (the kind sold at the hardware store are fine)
• Matches or a cigarette lighter

3. How people die (and how to not)

Last year, a group of scholars from the U.K. reviewed the records of all known deaths-by-volcano since 1500. That’s a total of 278,368 fatalities—a whole lot of people.

These people were generally killed by four things with funky names: pyroclastic density currents, tsunamis, lahars, and tephra. Below, I’ll break down each of these dangers and the steps you’ll need to take to survive them.

Pyroclastic density currents, sometimes called “pyroclastic flow,” are the mass of smoke, ash, and lava we usually associate with volcanic eruptions. They’re basically death clouds— they reach temperatures of up to 1,800°F and speeds of more than 400 mph. Virtually everyone caught in them dies instantly, making them the cause of about a quarter of eruption deaths.

This video documents a flow from the 1991 eruption of Mount Unzen in Japan. This flow killed 43 people (but those deaths are not shown in the video).

To survive them: Just don’t be there. The force and lethality of pyroclastic density currents should be reason enough to evacuate quickly if a volcanic eruption seems imminent. The speeds of these flows make them impossible to outrun, and their temperatures are impossible to survive. Thankfully, they very rarely travel even 10 miles from the site of the eruption. 

Tsunamis (basically massive waves) are often caused by volcanic eruptions that occur near water, either because of rock that has been displaced by the eruption or by earthquakes set off by the event. These waves kill nearly as many people as pyroclastic density currents, and their reach extends far beyond the immediate vicinity of the volcano. Deadly tsunamis have been recorded dozens of miles from volcanic eruptions.

To survive them: Stay away from beaches or low-lying coastal areas after a volcanic eruption, even if the eruption occurred some distance from your location. Try to get two miles inland or 100 feet above sea level. If you see water receding rapidly along the beach, get out fast—this signifies that a tsunami is incoming.

Lahars are mudslides set off by volcanic activity. Think of them as avalanches of dirt and lava—they’re often hot enough to cause burns, but generally cause death and destruction by enveloping people and buildings. Lahars and “secondary lahars” (slides set off some time after the eruption, usually by rain) have killed almost as many people at tsunamis and pyroclastic density currents. Almost half of these deaths occurred during the Armero tragedy, in which lahars buried a Colombian town, killing 20,000 people.

To survive them: When planning your evacuation routes, be wary of roads that traverse hillsides or that wind through canyons. Whenever possible, choose routes that follow ridges or go across open plains. Seek high ground immediately if you hear a dull rumble or roar. Never try to outrun a lahar—instead move diagonally to get out of its path.

Tephra is thick ash launched into the atmosphere by the force of a volcanic eruption. It can fall hundreds or even thousands of miles from the eruption, but generally only kills people within 40 miles or so. The ash makes breathing difficult, particularly for people with asthma. It can also cause roofs to collapse, crushing occupants.

To survive it: Do your best to avoid breathing the ash. Wear a respiratory mask if you have one, or else wrap a wet cloth around your nose and mouth. Don’t try to drive away, as heavy ash will likely clog up your car’s machinery. Instead, shelter in a nearby building while the ash settles and seal off windows, doors, and air vents. Be sure to choose a building with a sturdy roof and try to clear ash from the roof from time to time.

Those are the big dangers, but not the only ones. If caught near a volcanic eruption, you should also remember to:

• Take cover from falling debris; volcanoes spew rocks and “lava bombs” into the air, and these rain down like bullets.
• Never cross the path an active lava flow. These flows move slowly, but crossing one may leave you trapped.
• Avoid geothermic areas like hot springs and geysers. These weak points in the earth’s crust may collapse, erupt, or spew toxic gas during an eruption.
• Don’t drink the tap water. Ash will likely contaminate public water, so drink bottled water until officials give the OK.
• Pay extra care on the roads, even in areas far from the eruption. Drivers are likely to be panicked, and emergency services will be less available.

More than anything, though, the key to surviving a volcanic eruption is being far away from one. Stay abreast of the measurements made by USGS, keep an eye on the news, and get the hell out of there if officials call for an evacuation.

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Do you have other tips for survival a volcanic eruption? Share them with us at [email protected]