Monday, November 29, 2010

The Science of Snowmaking!

Way back in the old days (1970's and before), ski resorts world wide depended on natural seasonal snowfall to get the lifts turning. Needless to say the ski seasons were not that good, unless you enjoy hitting rocks and skimming over mud flows. In this new modern age we don't have to wait for the snow gods to provide. All we need is some water and good old compressed air.

#1. Internal Mixers (Snow Guns)

The science of snowmaking is actually pretty simple. So simple in fact that I made my own snow gun using some plumbing supplies from my basement. Here is what it looks like:

Anyone can make a snow gun from simple plumbing parts around the house, from a home improvement store, or local hardware story. But you do need two more things to make the snow fly. An average garden hose (or pressure washer) hooks up to the very bottom by the valve handle which adjusts water flow and the silver hook up on the middle left is a quick clip for a basic air compressor. When the air and water mix internally inside the long brass tube on the upper left it's forced out of a small hole at the end cap. When it comes out it looks like a white mist but it's actually in liquid form still. Assuming it's cold enough and humidity values are low enough the "white mist" will slowly float down to the ground and freeze in mid air. This is just a smaller model of what the resorts have but they run by the same principles.

You can use your snowmaker all you want, but if the "wet bulb" temperature is above 27 degrees F then you'll only be making rain. The wet bulb depends on the current air temperature and humidity. The current wet bulb can be found easily by using the chart from Snow At Home. (Humidity % across the top, and temperature down the side)

The maximum temperature you can have to still make snow is 39 degrees at 0% humidity, but we live on the east coast and the humidity is always high. Basically local resorts like Mountain Creek wait till the air temperature is at or below 27 degrees F before they turn on the guns and pump out the white gold.

#2. External Mixers (Fan Guns)

The snow guns are very cheap to buy and easy to use but require an air supply. The fan gun is good way to for resorts to avoid building huge compressors and they even produce greater quantities of snow. We've all seen these machines on the mountain side but just incase you haven't been paying attention this is what they look like:

The fan gun can be on wheels for towing, mounted to a pole, or mounted on a swivel so they can spread the snow over a larger area to reduce grooming. Instead of the compressed air mixing with the water in the snow gun, these guys have a fan built inside the drum and jets of water are injected into the spinning blades. Basically this produces the same "white mist" and runs off the same principle with the wet bulb temperature.

#3. When can we expect weather conditions that allow for snowmaking?

As we now know, resorts need not only low temperatures to make snow but low humidity as well. It could be snowing outside at 30 degrees but unfortunately snowmaking won't be possible because of high humidity. We need a dry cold air mass and that looks to be in the cards by the beginning of next week.

After a soaking rain storms this week expect cooler conditions for the weekend with marginally cold air (not cold enough for massive snowmaking). By Monday the 6th of next week a system will pass over the area bringing some natural snow, it's hard to tell right now but it looks like the Mid-Atlantic will get the bulk of snow with us on the northern fringe. That could always change so we need to keep a close eye on this one. Either way, the back side of this system will draw colder air down from the north with it's counter clockwise flow and the guns will start blasting. It looks like the snowmaking window could last through most of the work/school week. Hopefully Mountain Creek will be able to pump out enough snow and get it groomed up by Saturday the 11th. Their projected opening day.

Below is a map from the European weather model of Dec 6th:

Stayed Updated! Check back daily for weather outlooks in Morris, Sussex, and Warren counties. Questions? Comments? Email me or comment below.


weather said...

weather forecast from GFS,

snow rain maps

Darren Milliron said...

The GFS is ok, but the physics in the European model is by far more superior.