when was the last time it erupted?
January 2008
1980 eruption of Mount St. Helens
This activity lasted until January 2008.
what happened after the mt st helens eruption An earthquake which caused the entire weakened north face to slide away, creating the largest landslide recorded
wiki:20190524
1980 eruption of Mount St. Helens [SEP] 2004–2008
The 2004–08 volcanic activity of Mount St. Helens has been documented as a continuous eruption with a gradual extrusion of magma at the Mount St. Helens volcano. Starting in October 2004, there was a gradual building of a new lava dome. The new dome did not rise above the crater created by the 1980 eruption. This activity lasted until January 2008.