I'll be racing in the Arrowhead 135 which is a footrace along the Arrowhead snowmachine trail in Northern Minnesota in February. I plan to be out for 50-60 hours, potentially very cold conditions mixed with some exhaustion and dehydration to chill me a bit more. There are very few places to get out of the cold so I will be on my own for almost all of it. I will need to stop and melt snow, rest, sleep, etc periodically and plan on throwing insulating layers over my damp clothing to keep me from freezing solid. Have MH Chugach 3D pants for my legs... but what about the upper body? Not sure my thin down sweater will be enough. Would the MH Chugach Jacket be enough? Marmot Mountain Down Jacket is another option I've been eyeing, or the Marmot Cirque Down Jacket (both have down hoods). I may be getting an insulated vest and could work that into the system as well.

Solution needs to be warm yet lightweight and packable (of course!)

Ideas?

Great race! I'm hoping to do it in 2008 on bike.

You're going to be wet potentially so perhaps a synthetic top is better. Something like the Patagonia DAS parka maybe? That way the moisture can dry off your under layers and move into the parka which should still keep you reasonably warm even when it gets wet. If you get a down parka soaked you may not get it dry over the length of the race.

Go to the
RBH Designs - Testimonials - by Rocky Reifenstuhl

This might give you a couple of ideas for what to wear while you are running your race.

I am curious about vapor barriers and like the idea of less clothing weight (although am not sure about how I will like swimming in my own sweat, since I sweat quite a bit)... I might give it a try before the race if I can afford it this year.

Thanks for the link.

The Patagonia DAS jacket looks good as well...

Alec-I lived in Minnesota for 14 years. During that period it was not uncommon to get a week straight of January night time wind chill temps in the -30 range. I will assume that will be your worst case weather scenario to plan for.

It is highly unlikely that you will have to deal with rain and most DWR finishes should be adequate for the snow. For insulation thickness estimates I will use the average of 28 of the most common high loft insulations used in clothing and sleeping bags. Polarguard 3D / Delta are at the low end of the efficiency spectrum; Climashield XP / Exceloft are in the middle, and Primaloft One / 800 fill goose down are at the top. From the middle values I quote there is a variance of about 29% either way depending on materials, their water content, and their loft.

While running, you will generate at least 7 METS of energy. At this pace and my estimated worse case temps, you will only need about .34” of highly breathable insulation on your body. Close fitting Polartec Powerstrecth or Powerdry long underwear, 300 weight fleece insulation, and a wind shirt/pants should be close to optimum (.34”) for torso insulation by ventilating on climbs.

When cooking or resting, you will only generate ~ 2 METs. This will require approximately 1.2” - .34” (layer 1) = .86 (layer 2) of incremental torso insulation. Your MH Chugach 3D pants (2.7 oz/yd2) would only provide only .6” of the needed incremental leg loft. The matching jacket increment would be the same for the upper torso. If you decide to use the MH Chugach combination and the temp is near -30 windchill, you will probably have to generate some additional heat by isometrics to stay warm. Note that you would also need to augment the layer three value by what you didn't wear for layer two.

When sleeping, you will generate ~.8 METs. This will require wearing your layer 1 and layer 2 clothes plus supplementing them with a bivy, winter pad, and a quilt / bag (layer 3). Layer 3 needs to provide 3’ - .86” (layer 2) - .34” (layer 1) = 1.8”. I recommend a synthetic bag or quilt for this layer (optimally Primaloft Sport) so that moisture from your clothing can be effectively dried out while sleeping. If down was used, the dew point would occur in the down layer causing it to loose its insulation value.

Edited by richard295 on 10/26/2006 13:26:18 MDT.

Wow Richard. Excellent food for thought.

I have focused on synthetics (pants, jacket, sleeping bag) for the reasons you state. I will be unable to stop myself from sweating and will not be carrying multiple changes of clothing so will need to do some drying in my bag and jacket/pants. (I may play with VBLs a bit but may not have that sorted out in time for this race.)

I was thinking of combining a Primaloft vest with the Chugach jacket... more insulation when stopped and I can use the vest while moving slowly at night in the cold.

Alec-A Primaloft One vest won't provide you with the breathability that you will need while racing and a VBL would be even worse for ensemble layer 1. A Primaloft One vest augmentation would be excellent for ensemble layers 2 and 3.

One more question Richard... What is the formula to correlate METs to insulation (clo)?

Alec-I am heading out for a backpacking trip in a few hours and so won't be on again for at least four days.

When you sleep your Met rate is .8. When you work at a desk, your MET rate is about 1.6. Clo is inversely proportional to MET. For example, you would need ½ the insulation at a 1.6 MET activity as you do a .8 MET activity.

Well I ordered an Integral Designs Dolomitti Jacket with hood yesterday (on speacial for $156!). Looks like it will be a good choice. Now I need to get to the mountains to start testing...

I'd recommend against using a down sweater in a high perspiration situation like a race. It will retain way to much body moisture & lose its insulation.
I recommend a Thermolite Micro of Polarguard 3D insulated jacket. (Check this site's comparison chart for the manufacturer. I remember the jacket is $140.)They stuff small (esp. the Thermolite Micro insulation). Plus the synthetic fibers shed body moisture & retain loft far better than down in this situation.

Also try the Brigade Quartermaster online catalog for their excellent Softie Snug Pak insulation in British Mil Spec jackets. Softie is very similar to Thermolite Micro insulation and may be better.
After my experience with Primaloft's loss of loft I can't recommend it as a choice for synthetic insulation unless the current generation is much improved.
Eric

XC skiers shown doing Winter Olympic races wear bodysuits so carefully tailored that not one little wrinkle flaps in the breeze, I suppose to avoid air turbulence and extra weight. (Talk about fanaticism. Oh, we weren't talking about that? Oh well.) Would something like that be appropriate for a race like the Arrowhead 135?

Richard Nisley says, "While running, you will generate at least 7 METS of energy. At this pace and my estimated worse case temps, you will only need about .34” of highly breathable insulation on your body. Close fitting Polartec Powerstrecth or Powerdry long underwear, 300 weight fleece insulation, and a wind shirt/pants should be close to optimum (.34”) for torso insulation by ventilating on climbs." What kind of material do Olympic-level skiers use, and how does it compare to the above? (I need to know in case the American team calls and wants me.)

I've pretty much selected my active and passive layers...

While I'm moving:
Light-mid weight long-sleeve wicking top (Duofold or PowerDry)
GoLite Vapor VBL vest
Black Diamond microfleece vest
TNF Anorack (w/pit zips)

Craft Windstopper boxer-briefs
Marmot PowerStretch tights
Microfiber windpants

When I stop to melt snow, eat, set up my bivy I'll throw the ID Dolomitti parka and MH Chugach pants on over my damp layers to prevent flash freezing.

I did a 2-day, 45 mile solo traverse of the Snowy Range a few weeks ago with this setup. It hit minus 20 (f) early the second day and I was fine. As long as I keep fueling my furnace with calories, I put off a lot of heat.