Volcanic Eruptions

Ash from volcanic eruptions is hot enough to cause minor fire damage each minute. It limits visibility like a thick fog and can make air unbreathable, requiring characters to hold their breath or suffocate. Ash clouds generate ash lightning strikes, which typically deal moderate electricity damage but are very unlikely to hit an individual creature. Ash buildup on the ground creates areas of uneven ground, difficult terrain, or greater difficult terrain, and ash in the atmosphere can block the sun for weeks or even months, leading to colder temperatures and longer winters.

Pressure can launch lava into the air that falls as lava bombs: masses of lava that solidify as they fly and shatter on impact, dealing at least moderate bludgeoning damage and moderate fire damage.

Lava flows are an iconic volcanic threat; they usually move between 5 and 60 feet per round over normal ground, so characters can often outrun them. However, flows can move up to 300 feet per round in a steep volcanic tube or channel. Lava emanates heat that deal minor fire damage even before it comes into contact with creatures, and immersion in lava deals massive fire damage each round.

Mixes of hot gases and rock debris, pyroclastic flows spread much faster than lava, sometimes more than 4,000 feet per round. While cooler than the hottest lava, pyroclastic flows are capable of overwhelming entire settlements. They work like avalanches but deal half of their damage as fire damage.

Steam vents shoot from the ground, dealing moderate fire damage or more in a wide column. Acidic and poisonous gases released from beneath the surface can create wide areas of hazardous terrain that deals at least minor acid or poison damage.