The 'dio' (god) of the Rio Frio Ice Fest is WATER. Wait a sec? Is it not WINTER such that the cold is the star of the show? True, cold plays a role in assisting water by fluctuating temperatures from cold to colder to really cold, but it is water that can change its state of matter under many winter conditions, in shape and in volume.
On a training exercise for the 5k run, one of the events for the Ice Fest, I found myself up toward the Cat Creek Trail on the eastern slopes of the San Juan Mountains. Cloudy, with quick bursts of sunlight and occasional snow showers, muddy, snow packed and icy roads made me think of all the ways water can present itself to the surface of our planet. I was the only one parked where Forest Service Road 271 would normally continue on to the Cat Creek Trail. I parked, pulled my snowshoes out of my trunk and headed up the untracked road. My mind began to wander to all the states of water I was experiencing. First was snow, originally forming in the upper atmosphere, starting as a super cooled water droplet, freezing to a dust particle, then attracting more water vapor molecules as it drops toward earth, creating a beautiful six sided shape that dihydrogen oxide (H20) water drops form. We call it snow! There are as many different snowflake crystals as there are snowflakes, although I believe a few years back, scientists discovered two snowflakes that WERE exactly the same. And the number of snowflakes that have fallen within a hundred miles of Alamosa this winter would probably take up more zeros than I get on a blog post!
As I huffed and puffed my way up the road at 9,000 feet with the temperature in the low teens, my exhaled breath was producing a thick steam cloud. But is it actually steam? No, as we breathe and exhale carbon dioxide and other gases out of our lungs, we also launch out water vapor, droplets so tiny that it is water in a gaseous state. But, when your breath hits cold air, it loses heat energy rapidly in the cold, cannot remain a gas, condenses, and forms tiny water droplets that suspend briefly in the air like fog. They magically disappear.
As always, I stop several times on my trail treks in the mountains to observe Mother Nature's artistry. I noticed ice crystals in strange patterns on top of the snowpack in the shade but these crystals were not snowflakes. What were they? (1). Along a small creek bed were small aspen trees. On a few of their low branches was a form of strange frost arranged as wonderfully shaped crystals, gleaming even in the low light of the mostly cloudy winter day.Feathery in look, these crystals crinkled easily and fell when touched. Hmm, what were they and how were they different from the ice crystals on the snow and different from snow? (2)
I knew the terms 'hoar frost' and 'rime ice' but I was not exactly sure which were which or if they were two different names for the same thing... I went to the well - the internet library when I got home and lo and behold!! (1) - Hoar frost forms when water in its gaseous state comes in contact with something very cold and forms ice crystals. They can continue to form on one another and get quite large. (2) - What was on the aspen branches was rime ice. This is when super cooled water droplets in the air, essentially fog, come in contact with a surface, in this case the aspen branches, and begin freezing. The droplets continue to freeze into a crystalline form as long as the water droplets are in the air. Rime ice too, can get quite thick on a surface.
How does this apply to the Rio Frio 5K? We will be running on ice. But why is the ice on top of the flowing water? Open water will be flowing in strips on the surface where the moving water keeps the river going downhill but maintains a temperature above freezing. The next unique property of water, unlike many other liquids, is that ice is lighter than water. Water becomes its most dense, heaviest per unit volume, at 39 degrees Fahrenheit (4 degrees Celsius) and as it gets colder toward its freezing point at 32 degrees Fahrenheit (0 degrees Celsius) it becomes lighter, stays on top and begins to freeze and get colder as nighttime temps drop below Zero Fahrenheit. So, the interesting point here is that the ice is frozen and may be extremely cold but the water under the ice that is still flowing, and is a much warmer temp than the ice, most likely around 39 degrees. So, if you fall in during the run, be comforted to know that the water is much warmer than the ice on which you were running and from the forecast, much warmer than the air temp that will probably be around ZERO. Welcome to the Rio Frio Ice Fest 2017!!