NewsSnow Versus Air Temperature – Why?

FasterSkier FasterSkierJanuary 21, 20092

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Question:

Dear Toko,

I was wondering if you could help me. Your hot wax products should be chosen according to snow temperature. When preparing to train or go to an event, it is not always possible to establish the snow temperature in advance. Is there a way I can approximate the snow temperature from an accurate air temperature reading at the venue?

Answer:

Thank you for your question. I think there are many people asking themselves the same thing. The snow versus air temperature issue can be confusing, so let me first try to give some general information first before addressing anticipating snow temperature specifically.

First, there is no reasonable wax technician in the world who would ever pick a wax based on air temperature and humidity (except for when it is snowing – see below). Everybody considers snow temperature and follows much of the same thought process that I will describe below. We take these measurements (temperatures and humidity) primarily to anticipate how much moisture is in the snow. Air temperature will also tell you a lot about what the snow is going to be like in a while, but doesn’t tell you much about what it is like currently.

Snow reacts slowly to changes in air temperature. If the snow temperature is 20F and the air temperature is 30F, you can be confident that the snow is warming. This generally occurs in the morning. In the late afternoon, the air cools off and you might find a snow temperature of 30F and an air temperature of 20F which tells you that the snow is cooling.

Here is a common scenario which illustrates why depending on air temperature is simple folly: there is an event on Saturday starting at 10am. The overnight low Friday night was 5F. The forecasted high for Saturday is 35F. The air temperature at 10am will probably be about 25F. This means that according to the air temperature, a wax similar to a red/yellow mix should be used. However, the snow temperature in such a scenario would most likely be 10-12F still (because the snow warms far slower than the air does). This would justify using blue or a blue/red mix. There are huge differences in using a blue/red mix and a red/yellow mix. If you use a red/yellow mix on snow that is 12F, you will certainly have very slow skis. So, what to do?

Consider the overnight low. Then consider the forecasted high of the day and what time of day it might reach this high. Also consider whether or not this temperature will be everywhere or only in the sunny exposed areas. Try to guess the air temperature for when you might be skiing (somewhere between these two numbers). Then consider again the overnight low and the air temperature for when you anticipate skiing. Somewhere between these numbers, probably closer to the overnight low number, will be the snow temperature for when you will be skiing. That’s the temperature that you should wax for. The one major exception is if precipitation is anticipated. In that case, waxing should be done for the anticipated precipitation.In parts of the country falling snow acts “warm” and it glazes up like crazy requiring a warmer wax (pretty much everywhere but the rockies). In the Rockies, it often times snows very dry, even at warm air temperatures, and this often times requires a colder wax than the temperature would indicate.

Bottom line is that snow temperatures are quite predictable if you know the overnight low, the race start time, and have a feel for what the air temperature might be for when you are skiing. The combination of the snow temperature and observing what kind of crystals are present (corn, powder, etc) give you the most important information needed when determining what wax to use.

Recommended Iron Temperatures Chart

This chart as well as a whole lot of other practical information is located on the info center portion of the Toko US website. You can find it by going to www.TokoUS.com, clicking on Nordic, and then on Info Center. Or click this link.

Toko Iron Temperature Chart

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2 comments

  • Avatar
    michael@high-alpine.com

    January 21, 2009 at 5:04 am

    Every time I wax for a race a few questions and problems always come up; I would be greatful to hear thoughts on this:
    1. It seems I almost alway slightly burn my bases trying to iron on powder. How should I not burn my bases??? Won’t it last longer if I iron vs. rub.
    2. It also seems impossible to get an even layer with powder and is easy to use too much and still get an uneven layer in an effort to not burn the base. I like the block for that, but maybe powder is faster? Does anyone use the helix spray anymore?

    3. Is it 150 C moving pretty quickly looking for a sparkle? Some Toko material i have suggests 120 C, but that doesnt seem to be hot enough to get the powder into the base.

    4. When melting HF or LF Blue, do you want to see the wax be liquid after the iron passes? if it is not liquid in some sections is that ok? If when scraping, it chips off does it really go into the base?

    5. Scraping. I never know if I am scraping too much wax off. I use a sharp (i keep it sharpt with a file and toko ceramic sharpener).

    any tips would be appreciated. i have read the whole Toko US info and find it helpful, but not adressing these specific questions.

  • Avatar
    ianharvey

    January 21, 2009 at 8:46 am

    Michael,
    1. Rubbing on and rotocorking works superbly. I generally do two applications (rub on, rotocork, rub on, rotocork, then brush with nylon polishing and polish with pad) to ensure durability. If you want to iron, I’ve had the best results with having the iron really hot (over 150C) and moving it fairly quickly so the base is not just black behind it. You will not burn your base as the iron is moving (like the finger through the candle). Then after it cools, I rotocork it which speeds it up. Somehow the finish is faster, especially in powder snow, if the fluorocarbon is rotocorked.
    2. When the old HelX worked, it was awesome. It was really fast and durable. Sometimes it was a liability though in conditions such as dirt or dry falling powder snow. The new HelX isn’t as durable, but is very predictable and fast having the same properties as the new JetStream waxes. Due to it’s durability issues though, it is more for short races.
    3. I go 160C actually, but I keep the iron moving. We as a company recommend 150C. Because the amount of heat the ski feels is a combination of time and heat (not just iron temp, but how fast the iron is moving), I think sometimes talking about iron temp is misleading as it is only one of the two factors. Behind the iron, it should not be JetBlack (too slow or too much heat) or totally white and flaky (too fast or not enough heat).
    4. This depends a lot on the temperature of the room where the ironing is being done. In general though, yes, you want it to be liquid immediately behind the iron. If the wax chips when it is scraped (with the exception of the groove), then not enough heat was used and there is air between the base and the wax and the wax isn’t going in.
    5. Make sure that your scraper doesn’t have a burr. The flatter your base is, the more you can scrape. If your base is concave or convex, you need to stop earlier and remove the rest with the brush. Best solution of course is to get the skis stoneground and do it right.
    Thanks for your excellent questions
    Ian

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