Mount St. Helens released a thick plume of white steam Friday afternoon more than a week after a flurry of earthquakes began in the region.
Scientists aren't expecting anything nearly as powerful as the 1980 eruption that blew the top off the mountain and killed 57 people.
However, scientists this week said the way the volcano has been acting indicated an eruption was imminent.
The scientists suggested that ash and rock from a blast could land up to three miles from the volcano's crater in southwest Washington.
Earthquakes ranging from magnitude 2 to 2.8 were recorded earlier this week, possibly weakening the lava dome in the crater of the 8,364-foot mountain.