The largest nuee ardente eruption of Santiaguito since November 1929, occurred April 19, 1973. The nuee descended the valley of the Rio Nima II for a distance of about 4 km. The ash flow itself was restricted to the river bed, but the hot gas cloud devastated an area of more than 3 square kilometers extending hundreds of meters on both sides of the river bed. Because the ash cloud stopped about 2 km from the nearest habitations, there were no fatalities.