Adventure Idea: Asteroid Impact

What would the effects be when your fantasy world would be hit by an asteroid impact?

An asteroid impact speaks to the imagination. There have been Hollywood blockbusters about this topic such as Armageddon and Deep Impact. But things got quite real in 2012!

An asteroid impact on a fantasy world


In 2012, an Asteroid named DA14 passed swiped passed earth. Scientist believed that the chance that the asteroid would impact earth was about 0.031 percent.

That is a higher chance than winning most lotteries. Looking back now, we were quite lucky. It passed us at 17.000 miles (about 27.000 km). That is closer to the earth than some of our satelites.

But what would have happened if the asteroid would have impacted earth, or a fantasy world like earth?

A Small Asteroid

Lets use an asteroid based on DA14 as a base for the asteroid that will hit our fantasy world.

The asteroid impacting our world is the size of about half a football field wide. An asteroid of this size would not mean the end of the world, but it is big enough to create an interesting event in our fantasy campaign.

  • The impact would have the power of approximately 2.5 the times of the Hiroshima bomb.
  • It would destroy a city the size of London in an direct impact.
  • When the asteroid would hit land, it would create a crater 0.8 miles (1.2 km) wide and over 500 ft (150 meters) deep.
  • In the case the asteroid would hit the ocean, it would create a splash up to 6 miles (9.5 km) high.
  • An impact close to the shore, would create a large destructive wave.

A reasonably small impact like this would be an impressive and interesting event for your fantasy campaign. Or it could be a great piece of lore for an area in your world.

A Large Asteroid

Next lets take an asteroid that is about twenty times the size of our previous one, making it about half a mile (0.8 km) in width.

  • The impact would instantly destroy anything within about 60.000 miles (96.000 km). This is about the size of Portugal, or the state of Virginia.
  • A land impact would cause so many dust particles to enter the stratosphere, it would block out the sun and create an impact winter.
  • The impact winter could last a few years up to decades, depending on the area of impact.
  • If the impact would hit a deep ocean, the amount of water particles that would enter the stratosphere would cause an instant greenhouse effect.
  • In either cases, the temperature change would upset nature tremendously. Causing a lot of vegetation to be destroyed.
  • During the recovery time, animals will have a hard time finding food.
  • Many races would be brought to the brink of extinction.

A world recovering from a large asteroid impact could be a great idea for a dark, post-apocalyptic, fantasy campaign.

Adventure Seeds

  1. An asteroid destroyed half of an Elven city.
  2. Once a thriving city, now nothing more than ruins in a swamp. Caused by an asteroid impact in the nearby sea.
  3. Dwarfs are mining an asteroid crater for precious metals
  4. A necromancer claims an asteroid crater as his own, and raises thousands of people and animals from the dead.
  5. Hundreds of refugees come from the south, claiming their lands have been destroyed by a fiery ball from the skies.
  6. After a recent impact, Orcs have claimed the crater as a holy site.
  7. Days after a fiery rock came from the skies, a mysterious disease spreads through the lands.
  8. A huge asteroid brought destruction upon the lands and darkened the skies. Now, ten years later, the sunlight slowly starts to return.
  9. The king orders everyone to evacuate the city. The council of wizards have discovered that a rock from the skies will destroy the city within a fortnight.
  10. An old lake turns out to be an asteroid crater, and a mysterious object rests on its floor.

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