Doing a little research on the threat level from Mount Shasta.

The scientists say this:

 Volcanism at Mount Shasta is most conspicuously characterized by its strongly episodic character. This seems to be true both

on the longer-term scale of the several component cones of the compound stratovolcano and is recorded as well in individual closely spaced eruptive events, generally separated by longer intervals of quiescence. Consequently, it is to be expected that
any return to eruptive activity at Mount Shasta might be followed closely by further events within relatively short periods of time. For example, the opening of a new vent, such as occurred to form the Shastina cone about 11,700 years ago, could usher in a century or more of repeated lava eruptions and even the growth of a new cone segment. Eruption and partial collapse of dacitic domes, such as those that plugged the summit craters of each of the main cones of the Mount Shasta stratovolcano, have produced extensive pyroclastic flows, both mantling the slopes of the mountain and extending down surrounding drainages as far as about 30 km.

If things go wrong (right), I might wake up some night, look out the  window, and see something like this.

The most likely hazardous events at Mount Shasta are always debris flows (lahars). These can be small or large and can be triggered by eruptive events, either effusive or pyroclastic,
but are produced even more frequently by meteoric events. They can occur on any side of the mountain, but the most frequentand largest debris flows have occurred in the drainage of Mud Creek on the south side. A particularly damaging sequence of mudflows and floods occurred on Mud Creek in 1924 (Hill and Egenhoff, 1976), inundating large areas on the lower slopes, entering the drainage of the McCloud River, flowing into the Pit and Sacramento Rivers, and producing muddy floods as far away as San Francisco Bay. These debris flows resulted from a summer melting event after an especially warm summer that produced rapid melting of the snow cover on Mount Shasta’s glaciers, an abnormal release of water from the Konwakiton Glacier high
on the south side of Mount Shasta, and breakup of the glacier.

A future event of similar magnitude would now probably be contained within the Shasta Lake reservoir, about 45–50 km downstream from the base of Mount Shasta, but the consequences could well affect many more people than they did in the early 20th century. Smaller but still consequential debris flows on the slopes and drainages of Mount Shasta are produced every few years by heavy rains, especially late-summer thunderstorms.