One of the unexpected side benefits of these eruptions has been the deposition of ash and pumice layers that are rich in nutrients and support the abundance of wildflowers throughout the mountainous Pacific Northwest. Even as volcanic forces were building up this land, the slow, inevitable power of glacial ice began to shape and form it. The weight of the snow presses the air out, packs it down tight, and compresses it into ice. Gravity pulls the ice down the mountainside, both scouring and smoothing the bedrock as it goes. Freezing and thawing breaks rocks from the adjacent slopes, and they fall onto the glacier's surface.
More debris is picked up by the passing ice.
This is an inexorable process that continues today and will alter the mountain in the tomorrows to come. Yes, the process is simple, but it deals in forces that are beyond the control, and perhaps comprehension, of humans.