Most likely eruptive scenario at Mount Shasta
The next eruption at Mount Shasta would likely involve weeks to months of precursory earthquakes and ground deformation followed by a series of steam explosions blasting a deep crater at the summit of the volcano. Steam explosions would be followed by slow extrusion and accumulation of partially molten rock in the crater, leading to the formation of a steep-sided lava dome. Periodic collapse of the growing dome would generate explosions with vertical ash columns up to 8 km (5 mi) high. Fast moving avalanches (pyroclastic flows) of hot dome rock racing down the flanks of the volcano would melt ice and snow creating mudflows (lahars) capable of flooding drainages many kilometers away.