Shrike
it has nothing to do with packing it has to do with ice subliming directly into steam and scorching the pan. If you don't have any liquid water to start with do this:

Warm the empty pan holding it above the stove maybe six inches and put in one half teaspoon of snow, no more. Swish it around in the warm pan until it melts, add one more half teaspoon and do the same. Now warm it up a bit closer to the the heat and add one whole teaspoon and swish it around and it should melt, then add another teaspoon. continue doing this. In a minute or two you will have a couple ounces of water and you can put the pan on the stove and slowly add snow but not enough snow at any one time to absorb all of the water. stir constantly. I like to then heat it up pretty hot and then add more snow so it melts instantly. Keep the pan water warm so there is no condensation on the bottom so the stove burns better.
Jim