Muir Snowfield: is it a glacier?

Yesterday while touring on the Muir Snowfield past crevasses, some large, some small...I began to wonder, what is the difference between a snowfield and a glacier?<br><br>The Muir snowfield seems like a glacier to me...is it one? Why, why not?<br><br>Any idea how deep the snow on the MS is? How old the lower layers are? Any other interesting facts would also be appreciated.<br><br>

Generally, a glacier is permanent ice that moves downhill under its own weight. Cracks are a good indicator of movement.<br><br>I'd be curious to know how thick the MS is though. Is it going to melt out with a few more low-snow years?

Yes, seeing those crevasses certainly opened my eyes and made me wonder the same thing. They sure looked like glacier crevasses and I think they would act the same if someone were to fall into them. Maybe in the past, when the Muir snowfield got its name, there was never enough summer melting to reveal the existence of the crevasses, so it was just called a snowfield. The snow/ice there must be the leftovers from the much greater glaciation of the past. Would the answer to whether or not it is now a glacier depend on whether the mass has any movement to it?<br><br>Added: Phil posted while I was writing. Those crevasses looked quite deep, so my guess is that it would take more than a few more bad snow years/summer melting to get down to bare rock.

I just wanted to add that most people refer to the Palmer snowfield as a snowfield, yet on the USGS topo its labelled the Palmer Glacier. It has no glacier features that I'm aware of. I wonder if it'd still exist late in the season if it weren't for how they farm it (push snow on it, groom, etc)

<br>Was thinking of how thick the Muir snowfield/glacier is and was and started looking around on the web. Found a interesting article about the Paradise Glacier caves and reminded me of how much of a melt is happening just around the corner<br><br> "By the end of 1973 the map of the Paradise Glacier Cave System showed more than ten miles of mapped cave passage." <br><br>The whole page can be found at<br> glaciercaves.com/html/rise_and_fall_of_paradise_ice_.html

CW

As I recollect (glacial geology class at Whatcom Community College, 1999), a glacier consists of: a perennial accumulation of snow compacted by its own weight into ice, more than a tenth of a square kilometer in extent, exhibiting plastic flow (current or, in some definitions, past). I've always considered the Muir a glacier based on the fact that any permanent snowfield of that size is bound to meet the other requirements (ice and movement), whether or not evidence is apparent on the surface. On the other hand, it's obvious I'm no expert. <br><br>Note that steep snowfields exhibit creep, which is in part a plastic deformation similar to that seen on glaciers (in part it apparently involves shrinkage as seasonal snow consolidates). In the absence of ice and significant size, however, small permanent snowfields don't qualify as glaciers. I don't know where the Palmer Snowfield falls in all this, but even if was a glacier at some point in the recent past, the lack of any obvious signs of movement (for example, crevasses, morrainal accumulations, surface scratches on bedrock, or cirque formation) suggests that it's not curently. <br><br>The above represents a significant portion, maybe 10 or 12%, of all that I remember from my recent investment in college (3.5 years) and grad school (2 years).