how large was the ash column?
A huge ash column grew to a height of above the expanding crater in less than 10 minutes and spread tephra into the stratosphere for 10 straight hours
1980 eruption of Mount St. Helens
As the avalanche and initial pyroclastic flow were still advancing, a huge ash column grew to a height of above the expanding crater in less than 10 minutes and spread tephra into the stratosphere for 10 straight hours. 
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 when was the last time it erupted? January 2008 and before that? October 2004 and before that? Between 1980s to 1991 which was the deadliest eruption? March 27, 1980 eruptions describe the build up of this eruption that you just mentioned On March 20, at 3:45 p.m. Pacific Standard Time, a shallow magnitude 4.2 earthquake centered below the volcano's north flank, signaled the volcano's return from 123 years of hibernation. A gradually building earthquake swarm saturated area seismographs and started to climax at about noon on March 25, reaching peak levels in the next two days, including an earthquake registering 5.1 on the Richter scale. A total of 174 shocks of magnitude 2.6 or greater were recorded during those two days how far did the landslide reach? He traveled and moved across Spirit Lake's west arm, part of it hit a ridge about north, some of the slide spilled over the ridge, but most of it moved down the North Fork Toutle River, filling its valley up to deep with avalanche debris were there mudslides as well? Yes, mudflows from the southern and eastern flanks had the consistency of wet concrete as they raced down Muddy River, Pine Creek and Smith Creek to their confluence at the Lewis River is it true there were side way blasts? Yes what were the effects? 57 people known to have died in that day's eruption succumbed to asphyxiation, while several died from burns
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1980 eruption of Mount St. Helens [SEP] Ash column
and was seen on the ground in Denver, Colorado, the next day. In time, ash fall from this eruption was reported as far away as Minnesota and Oklahoma, and some of the ash drifted around the globe within about During the nine hours of vigorous eruptive activity, about 540,000,000 tons () of ash fell over an area of more than . The total volume of the ash before its compaction by rainfall was about . The volume of the uncompacted ash is equivalent to about of solid rock, or about 7% of the amount of material that slid off in the debris avalanche.