Saving snow for the summer

As a wee lad, I tried saving snowballs to break out in the heat of summer hoping to surprise my brother in the back of the head. I never quite ended up with fluffy goodness; I always opened the carefully sealed Tupperware to find dense ice-bombs (not something to hurl at an older brother).

Well, it’s been many years and now that spring is nigh (it is nigh, isn’t it?) and I have a four year old who [del]can’t fight back[/del] will be just as excited to save snow for the summer.

…and just as disappointed when he finds lumps of ice.

Is there anything I can do to help out? I figure that as an [del]grown-up[/del] old person with access to vacuum sealers, blow torches and freezer thermostats and the Internet, I might be able to help him achieve better results.

Plan a summer trip to Mt. Hood in Oregon. Someone is bound to be skiing on the slopes even in summer.

Just find a hockey arena and wait out back for a Zamboni to dump it’s load. Replace the freezer ice with Zamboni snow.

snow looses its fluffy structure with time due to its own weight.

Well, getting the snow to be looser is pretty much the goal here. But I don’t think that’s what you meant.

The problem you have is that whilst the water is frozen - ie not liquid, you have not stopped all the interesting processes that the water undergoes. Water sublimates, that is even when frozen, it turns directly into water vapour. (Freeze drying is a process that makes use of this effect, allowing you to dry out something whilst preserving it structure. Hint - if you have a a sodden book, you can dry it out without further damage by putting it into a frost free freezer - it will take many months, but it will dry it.)

If you have water in a sealed container in a freezer, it will sublimate, and then later then vapour will precipitate out again. This runs is a continuous steady cycle, the result of which is that the fluffy (large area) snow tends to turn into a mass that has less surface area, and you end up with a lump of icicles.

The colder you keep it the better, but even in liquid nitrogen you will only slow the process. High pressure would also help. But a cryogenic pressure vessel isn’t usual domestic equipment, and I don’t know how much it would help, only that it would help to a degree.

Thank you! That was very clearly explained!