A volcano is a vent at the earth's surface through which magma (molten rock) and associated gases erupt, and also the cone built by effusive and explosive eruptions. Although there aren't any cone-shaped volcanoes in Teton County, we do have several active areas in and around Yellowstone National Park.

Volcanic Activity in Yellowstone National Park

The reason that Yellowstone has so many amazing thermal features such as geysers, mud-pots, and fumaroles is the volcanic activity underneath the surface. Yellowstone has a large caldera, which is a collapsed volcano, that encompasses a large portion of the park. Most people don't realize as they drive into the central geyser basins in Yellowstone, that they are actually driving into a volcano. View a map to look at the region that the Yellowstone caldera encompasses. Teton County extends to the southwestern edge of Yellowstone Lake, so technically part of the caldera is in our county.


I'm sure many of you have seen, or at least have heard of, the  docu-drama "Supervolcano". One of the more popular questions Emergency  Management has received following this production is, "Will that happen  here?" The answer is that we don't know for sure, but we will prepare  our citizens by teaching them about the risk, and also give them  instructions on how to prepare. The National Park Service and the USGS set up a great website answering some of the more common questions that have come up in regards to the "Supervolcano" movie.

Map of Yellowstone Caldera

Potential Impacts

A catastrophic large-scale eruption of the Yellowstone caldera would have dire impacts on the entire world, and not just Teton County. To learn about those, check the Yellowstone Volcano Observatory FAQ.

Loss of Life & Damage to Property

Loss of  life is the primary impact, and secondary to that is the damage to  property. Ash, being made of pulverized rock and glass, can get into  ventilation systems, engines, and buildings rendering vehicles and  structures unusable.

Cascading Events

Even a non-catastrophic volcanic eruption is a large-scale event. Like an earthquake, it is the other disasters that are triggered by the volcano that can make the event even more complicated. Volcanoes can trigger landslides, avalanches, flash floods, wildfires, weather such as acid rain, and other disastrous events.

Volcanic Cascading Event

A Long & Expensive Recovery Effort

Even without lava flows and pyroclastic events, the amount of ash that can be deposited following an eruption presents an expensive logistical problem for affected communities. Ash and lava can cause extensive damage to critical infrastructure and utilities as well.

Economic Losses

Not only is the recovery effort expensive, but if people are unable to leave their homes due to hazardous conditions outside, businesses will suffer.