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What makes better snow - Page 2

post #31 of 49
Quote:
Originally Posted by BushMogulMaster View Post
Cosmetic (powder) snow has an average density of 20lbs/cf. Base snow has an average density of 40lbs/cf. The best you can usually do with man-made is in the 27lbs/cf range (average snow density).
Do you if that is before or after the snow has settled?

A cf of water weighs about 62.5lbs. So that 20lb/cf cosmetic is about 32% water and that base snow is 64% water.

According to wikipedia, natural snow falling out of the sky is about 5% to 15% water and is settles to about 30%. So regardless, natural snow is much less dense than man-made.
post #32 of 49
Quote:
Originally Posted by learn2turn View Post
Do you if that is before or after the snow has settled?

A cf of water weighs about 62.5lbs. So that 20lb/cf cosmetic is about 32% water and that base snow is 64% water.

According to wikipedia, natural snow falling out of the sky is about 5% to 15% water and is settles to about 30%. So regardless, natural snow is much less dense than man-made.
After settling. Cosmetic snow as I refer to it is cosmetic natural snow, not man-made, btw.

But yeah, natural is most often less dense than man-made. Of course, you'll have your occasional wet storm that leaves some nasty dense snow behind. But 9/10 times, man-made will be more dense.
post #33 of 49
Herman K Dupre of Seven Springs here in SW Pa. is considered one of the most knowledgeable people in the world regarding snowmaking. He will be consulting on snowmaking for the 2012 Winter Olympics at Whistler. Herman Dupre holds multiple patents on snow making equipment and I see his HKD snowmaking systems just about everywhere I have skied. HKD's are tower A/W guns.
I have skied many cold winter mornings on freshly made snow at Seven Springs that can be described as velvet. I don't know this for a fact, but it seems like many times the surface was not groomed after snow making ended.
I could be wrong on this, but when snowmaking conditions are not optimum, the snow has a tendency to slab up and break away, which I would think couldn't occur if it was groomed.
Seven Springs has an excellent snow making system that is not dependent on pumping water to all the guns. The water flows by gravity from the top of the hill to the snowmaking guns and the volume of water they can flow I believe is in excess of 25,000 gpm.
Hopefully I'm not a fountain of misinformation on the information given, but we're extremely fortunate here to have the snowmaking expertise and system that is available. I've witnessed many times Seven Springs coming back from an ice storm or horrible rain event and offer excellent skiing with optimal snow making conditions in 2-3 days.
post #34 of 49
Thread Starter 
I have skied a nice soft powdery product at Killington and most noteably Stein's Run, Sugarbush. It was real nice.

But most of the time when you go under the gun, the snow is sticky and you can almost come to a complete stop fast. This happens even when it's cold. I understand Killington is blowing some nice soft snow right now and that's pretty sweet. What's with the other areas blowing cement?
post #35 of 49
Quote:
Originally Posted by Paul Jones View Post
I have skied a nice soft powdery product at Killington and most noteably Stein's Run, Sugarbush. It was real nice.

But most of the time when you go under the gun, the snow is sticky and you can almost come to a complete stop fast. This happens even when it's cold. I understand Killington is blowing some nice soft snow right now and that's pretty sweet. What's with the other areas blowing cement?

The reason it happens when it's cold is because they want it to happen. Up the water output, and you get heavy sticky snow. It's base building. Low density snow gets worn out fast, and doesn't last long into spring. If you blow a real wet solid base, then you're good to go. As the season progresses, the product will become lighter in general, since they will be going for base depth vs. base durability.
post #36 of 49
Quote:
Originally Posted by Paul Jones View Post
Do you know of any other types of snow making equipment?
Yeah. Ullr/God/Mother Nature. The "snow" that comes out of those guns blows. Hate to sound like an elitist powdersnob, but it's true.
post #37 of 49
Quote:
Originally Posted by tromano View Post
My favorite snow makers are clouds.
Same here. I wish we'd get some.
post #38 of 49
Thread Starter 
Quote:
Originally Posted by BushMogulMaster View Post
It's base building. Low density snow gets worn out fast, and doesn't last long into spring.
Base building is one thing, but quality snow is light soft and skiable. There are ski areas that make the effort to blow a quality snow for their customers and it's noticeable. On a Saturday at Jiminy and they are blowing cement during the day on their best trails even when the base is fine. All they have to do is adjust the mixture.
post #39 of 49
I'm thinking that they're thinking let's make as much base as we can before it warms up again. We're talking Massachusetts and from what the weather's like here in CT. I know it ain't below freezing at Jiminy. If you're die-hard enough to ski opening day, then you should be man enough to take whatever they're dishing out! That said, and thinking about it, I don't think Jiminy is particularly good at the snow quality thing.

Paul, we're gonna be up near you visiting family tomorrow, but no skiing for me until Dec. 8.
post #40 of 49
Interesting stuff. We're getting rain here in Southcentral Alaska, and it's not cold enough for our low elevation resorts to blow snow at this point. We did get a few inches coverages on our local hill before the warm snap, but then had to shut down.

Question: How does water temperature effect the ability to make snow, if at all? I was told a couple years ago by someone on our snowmaking crew that warmer water freezes faster and produces better snow than cold water when run through our guns. True? If so, can someone explain why? I can't quite get my mind wrapped around the concept.

Cheers,
post #41 of 49
Quote:
Originally Posted by trochilids View Post
Question: How does water temperature effect the ability to make snow, if at all? I was told a couple years ago by someone on our snowmaking crew that warmer water freezes faster and produces better snow than cold water when run through our guns. True? If so, can someone explain why? I can't quite get my mind wrapped around the concept.
This is a very interesting question I don't know the answer to, but I do know that the ski areas spend money on ponds to keep the source temp under what you'd find from most sources...somewhere below 45 degrees I think. In light of the next paragraph, I wouldn't be hugely surprised if it is true that the coldest water doesn't freeze the fastest, but I would still think things like nucleators in the source would be more important.

The phenomenon of warmer water freezing faster than colder water has been known for millenia by various people and was discussed by dudes like Aristotle, but it wasn't discussed in the modern literature until a high school student in Africa brought it up in the latter half of the last century. The Mpemba effect it is called.

There is little consensus on the exact mechanisms through which the effect takes place in various situations...you would think there would be an impetus to understand it well and see if/how it could be applied in industrial processes like snowmaking or icemaking...but for some reason it doesn't appear that interesting to physicists. Whoever does publish something conclusive will probably do a lot of CFD...

/I like this topic, sorry for dorking this up.
post #42 of 49
It isn't that interesting to physicists because it is a simple phenomena and occurs only in limited circumstances.

Hot water in a completely insulated container that loses heat solely at the surface will freeze faster than cool water in an identical container. This minimizes radiant and conducted cooling and maximizes cooling through evaporation. The warmer water both evaporates faster, driving off heat quickly, and reduces in volume, so there is less water to cool.

I put in the snowmaking systems at Alyeska and Hilltop, and ran them for the first few years. I don't know how much has changed with the systems there, but I do know when I worked there, we were able to make more snow when it was warmer. That has nothing to do with physics, unfortunately, and everything to do with water supply.

Both ski areas relied on creek water for snowmaking. As cold weather set in, the creeks provided less water. By midwinter, the creeks had frozen entirely, and snowmaking ended for the season.
post #43 of 49
Thread Starter 
Quote:
Originally Posted by crank View Post
If you're die-hard enough to ski opening day, then you should be man enough to take whatever they're dishing out! That said, and thinking about it, I don't think Jiminy is particularly good at the snow quality thing.

Paul, we're gonna be up near you visiting family tomorrow, but no skiing for me until Dec. 8.
They have great technology and now they have the Zepher to provide extra electricity. If they want to they can.

What's up with Dec 8th, Judges orders?
post #44 of 49
Quote:
Originally Posted by Harry_Morgan View Post
It isn't that interesting to physicists because it is a simple phenomena and occurs only in limited circumstances.

Hot water in a completely insulated container that loses heat solely at the surface will freeze faster than cool water in an identical container. This minimizes radiant and conducted cooling and maximizes cooling through evaporation. The warmer water both evaporates faster, driving off heat quickly, and reduces in volume, so there is less water to cool.

I put in the snowmaking systems at Alyeska and Hilltop, and ran them for the first few years. I don't know how much has changed with the systems there, but I do know when I worked there, we were able to make more snow when it was warmer. That has nothing to do with physics, unfortunately, and everything to do with water supply.

Both ski areas relied on creek water for snowmaking. As cold weather set in, the creeks provided less water. By midwinter, the creeks had frozen entirely, and snowmaking ended for the season.

Pleasure to meet you, Harry. I work at Hillberg -- the little ski hill on Elmendorf AFB across the valley from Hilltop. From certain vantage points on base you can see the slopes at Hilltop -- and I've noticed the snowguns working on the hillside at Hilltop (prior to this rainy warm spell) already this year. It still wasn't cold enough for our guns to work at Hillberg for more than a couple days -- and we started well after Hilltop did.

We pull our snow-making water out of a pond at the base of the parking lot, so we have water all winter if necessary. But we still have to add something to the water in the pumproom to get the best snow effect. I worked two winters as a cold-weather grunt on Hillberg's snowmaking crew and never really understood what I was doing from the theoretical point of view. This thread has been very informative and has given me a reason for why I was doing what I was doing, and why we got what we got as a result...

Happy Thanksgiving, everyone.
post #45 of 49
Quote:
Originally Posted by Jer View Post
Yeah. Ullr/God/Mother Nature. The "snow" that comes out of those guns blows. Hate to sound like an elitist powdersnob, but it's true.
This whole thread just makes me thankful I live close to ski hills that don't make snow. Skiing on artificial snow is like solitary sex--better than none at all but not much.
post #46 of 49
Quote:
Originally Posted by gnjantzie View Post
This whole thread just makes me thankful I live close to ski hills that don't make snow. Skiing on artificial snow is like solitary sex--better than none at all but not much.
Yeah, but skiing on artificial snow doesn't break the law of chastity.
post #47 of 49
Quote:
Originally Posted by UtahPowderPig View Post
Yeah, but skiing on artificial snow doesn't break the law of chastity.
In the Powder Day Saints it does...hehe.
post #48 of 49
Quote:
Originally Posted by trochilids View Post
But we still have to add something to the water in the pumproom to get the best snow effect. I worked two winters as a cold-weather grunt on Hillberg's snowmaking crew and never really understood what I was doing from the theoretical point of view. This thread has been very informative and has given me a reason for why I was doing what I was doing, and why we got what we got as a result...

Happy Thanksgiving, everyone.
Probably added Snomax or Drift. Both additives to increase snowmaking productivity. Drift is just a surficant that decreases surface tension of the individual water particles to help them freeze. It makes a slightly oily-like surface that's real easy on blades and power tillers compared to typical man-made.

Snomax is a biological-based additive. It is technically pseudomonis syringae, a bacteria found in nature (often on the underside of certain leaves). It acts as a high-temp nucleator, and is only really effective if your water source doesn't already have enough high temp nucleators (impurities act as nucleators, some low temp, some mid, some high temp). Sounds like your source probably lacked enough high temp nucleators to make a decent volume.

The reason you need high temp nucleators is this: each nucleator will freeze at a different temperature. One might not freeze until 8F, while one freezes at 16F, and another at 28F. Completely pure water itself (distilled) will not freeze until -40F. This is why you need nucleators to induce freezing. And if your snowmaking temps are in the 20s (which they often are for your key early season snowmaking time), you really need high temp nucleators. If they don't exist naturally in the water supply, you need to supplement with an additive.
post #49 of 49
Thread Starter 
Quote:
Originally Posted by gnjantzie View Post
This whole thread just makes me thankful I live close to ski hills that don't make snow. Skiing on artificial snow is like solitary sex--better than none at all but not much.
Makes me grateful when we have a powder day, (anything over and inch and a half).
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