Yellowstone Ash Map (image) American Geophysical Union Caption An example of the possible distribution of ash from a month-long Yellowstone supereruption. The distribution map was generated by a new model developed by the US Geological Survey using wind information from January 2001. The improved computer model, detailed in a new study published in Geochemistry, Geophysics, Geosystems, finds that the hypothetical, large eruption would create a distinctive kind of ash cloud known as an umbrella, which expands evenly in all directions, sending ash across North America. Ash distribution will vary depending on cloud height, eruption duration, diameter of volcanic particles in the cloud, and wind conditions, according to the new study. Credit Credit: USGS Usage Restrictions None Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.