Last fall, I visited Lassen. Lassen is the southernmost of the big Cascades stratovolcanoes. It erupted in the early 1900's. While I was there, there would be occasional ventings of steam or smoke from the crater.
A few days ago, I drove to Mt St Helens. The Johnston Observatory was open, and I stood near where David Johnston stood 30 years ago, in line with the crater and the blast of ash and debris that overwhelmed him seconds after he radioed a warning of the blast. I felt like I was looking into the mouth of a monstrous cannon as I looked up at the crater from a mere six miles away.
I listened to a Ranger's presentation about the activity in the Crater of Mt St Helens. As he was speaking, I watched steam venting from the dome in the crater.
Over the next ten minutes, the steam plume grew.
I know that this is the most heavily monitored and instrumented mountain in the world, but it was still unnerving to stand there and watch vapors escape from the depths of the earth by means of the crater dome in front of me.