In the fields we can see the boulders that are left behind as the softer muds are eroded away. There is no agriculture here because of the boulders. Farther up the road we can see the lahar flow sequence into the valley. This went for 30 miles. The lower ends of the muds are covered by the sediments of the great valley.
Lahars always come from explosive volcanoes, spraying magma.
When you see a lahar you know there was a distinct, explosive volcano. This is like Mt St Helens which has not yet turned to stone. Most of the Mt Lassen volcanics were violent. Another eruption of Mt Lassen will even affect us in Rocklin. We stop at Child's Meadow in the Lassen Peak region.