Typical of late season Colorado storms, the one this week dumped wet, heavy snow across the Front Range and High Country. Our field site received 38″ of the white stuff in one day!
Depending on your outdoor pursuits, late season snow can be a blessing or a curse:
- Skiing in a T-shirt is fun
- Wet, heavy snow snaps tree limbs and kills gardens/plants that couldn’t wait to bust out
But what about specific differences between this week’s snow and the snows of…say, February? (Which were pretty much nonexistent this year.)
Also check out ‘4 Tips to Keep Your Water Bottle from Freezing’:
Wet vs. Dry Snow
If you’ve spent time in the snow, even as a kid, you probably intuitively know or feel the difference. It has everything to do with the amount of liquid water per volume of frozen water (i.e. snow) – a la ‘density’. Pronounced: Duh!
However, the largest factors controlling the ‘wetness’ (high volume of water in snow) are:
The region (and, in fact, hemisphere) warms due to our orientation to the sun this time of year. So instead of zero to 20-degree nights, we have 30 to 40 degree ones. Any snow that falls is naturally ‘warmer’ (closer to the melting point) than colder (‘more frozen’) snow.
Although water technically freezes at 32 degrees Fahrenheit, I’m sure we’ve all seen snow on warmer days and standing water on days below freezing. A switch doesn’t automatically flip when the thermometer hits 32. Better to think of 20 degrees to the high-30s as a transition zone between frozen and liquid water. Let’s call 18 degrees the point at which things begin to change. Below which, stuff’s pretty frozen. Above which, stuff starts to melt.
OK, so what? Sounds like we’re splitting snowflakes here. But here’s how this directly effects you and I when we’re out.
- Staying Dry – Potentially the most important take-away, because it directly effects your ability to stay warm – and should factor in to your clothing/gear choices. Staying dry is paramount to staying warm and safe, due to evaporation and convection (two of the methods through which our bodies lose heat). In ‘wet’ snow (even 20 degrees), the proximity of your body (heat) to the snow can melt the snow even more (which is probably slushy to begin with) and now you’re kneeling/sitting/working in the equivalent of water. In wet snow conditions, it’s important to be using a vapor barrier such as a rainshell when in direct contact with the snow. Conversely, in very ‘dry’ snow (let’s say below 15 degrees) things stay pretty frozen – snow that lands on your clothes brushes away easily. It’s so cold (dry) that even your body heat rarely melts the snow. Somewhat ironically, it can actually be more comfortable (and safer) to be out in conditions between 0 and 15 degrees than on days between 20 and 40. In wet conditions, your footwear and any clothing that will come in contact with the snow should be waterproof – rubber boots, synthetic shells. In dry conditions, porous (breathable) materials become much more the way to go – wool clothing, leather boots.
- Shelter Construction – In slightly wetter conditions (18 to 30 degrees), snow sinters or ‘packs’ much easier and quicker than in very cold/dry conditions. It sticks better when there’s a higher moisture content. This is one of those lessons from building snow forts as a kid. Skiers like powder (dry/cold) snow. Kids like ‘packing snow’ (wetter/warmer) for forts. For example, when building a quinzhee (check out our instructional video) you begin by piling up a mound of snow and then let it sit long enough to sinter (stick together and become cohesive enough to hollow-out). The amount of time that takes varies greatly depending on the temperature/dryness of the snow, from 4-5 hours in incredibly dry conditions to less than an hour in wet conditions.[If snow shelters interest you, view our 3-part Snow Trench Emergency Snow Shelter video lesson.]
- Harvesting Drinking Water from Snow – Contrary to what you may think, melting snow for water isn’t as easy as filling a can with snow and putting it on a fire. Do that and you’ll end up with a burnt pot that’s still full of snow. The technique is to start with a little bit of water (in the pot, over the fire) and then slowly add small amounts of snow to melt. As the snow melts (water volume increases), you add more snow. Here’s where common sense returns to being correct: The ‘wetter’ the snow (higher quantity of water per volume), the faster it will melt and the more liquid water it will yield – and the faster you’ll produce drinking water from snow.
Have fun out there!