I think Mt. St. Helens might be able to rebuild itself depending on if erupts. If it keeps on erupting it won't get a chance to rebuild. If it doesn't erupt it will take about 140.5 years to go back to it's normal state. The reason it will take so long to rebuild is because it has to rebuild 4,213 feet of rock. You are probably thinking how could Mt. St. Helens rebuild itself? It grows over 1 inch every day. That's 300 feet every 10 years. That's a lot!