Mount St. Helens’ Crater Glacier continues to grow while most are shrinking

The title suggests this is unusual, but it's not really.

The simplest way to look at a glacier's changes over time is mass balance. A glacier accumulates mass, principally from snowfall in winter, which compacts into ice and flows downhill. It losses mass through what's called ablation - for a typical mountain glacier this is principally surface melt in summer, or for a glacier in polar regions it may be ice calving into the sea.

For obvious reasons, the accumulation zone for a mountain glacier will be at higher altitudes, and the ablation zone will be at lower altitudes. The equilibrium line altitude is the altitude at which mass lost equals mass gained.

As Mount St. Helens' glaciers disappeared following the eruption, the glacier(s) will start to regrow as snowfall causes ice accumulation above the equilibrium line altitude. Eventually, as the articles hints, the glacier will come back* into mass balance.

I've simplified this all somewhat, as there can be lots of other factors that influence mass balance (as the article mentions, rock cover will reduce surface melting).

*I say come back, as because of the natural variations in climate from year to year, mass balance is never steady-state.

As I prepare for trip #4 up that mountain (keep running into friends that haven't been and want me to take them), I'm surprised at the changes in the past ten or fifteen years since I first went up there. (Of course, those that climbed it >35 years ago will note even bigger changes.) The crater used to be a lot deeper before 2004 and the difference is readily apparent. The lava dome has grown, and now there's a new glacier. Not bad for something that's supposed to change along "geological timelines".

As for the article's quoted complaints about the cost of the new guided hikes, just the shear amount of toilet paper I see every time I go up (let alone other trash) there makes me somewhat supportive of the idea of requiring adult supervision to go via an easier route that acts as less of a filter than the much harder summer route to the rim.

I'm hoping they keep restricting access to the peak for a while. There's so many interesting things happening there from an ecological standpoint, and it's not like we're hurting for volcanoes around here.