Fire & Ice Ultra

Billed as Iceland’s Toughest Foot Race – and confirmed by those who’ve done it as one of the World’s toughest – the Fire & Ice Ultra takes 6 days to cross 250km of volcanic ash, glacial rivers, barren rock, grassy meadows, and everything else the Icelandic terrain can possibly throw at you.

Although the race takes place in summer, it can still get cold at night. Competitors need to carry their kit with them so, as always, a balance needs to be struck between what you’re reasonably prepared to carry and the warmth you need.


Down Sleeping Bag selection

The kit list requires a sleeping bag, with or without liner, which is capable of withstanding temperatures of 0°C. The most obvious choice from our main range therefore would be the M Degree 250, with a TOT (Typical Operating Temperature) of 0°C.

If you sleep cold, the M Degree 300 is even warmer. Otherwise, the Superlight base bag on our Design Your Own Sleeping Bag site allows you to create a bag of exceptionally low weight to your own specifications.

Regardless of which of these sleeping bags you choose, the option to have it made in water-resistant Hypershell is certainly worth considering, given the Icelandic potential for inclement weather and increased condensation levels in a small race tent.


S-bag TOT (Min Temp) Weight Packed size
Hght x Diam (cm)
°C  °F gm oz 
M Degree 250 0 32 390 14 21 x 13
M Degree 300 -3 26 445 16 21 x 13

Additional points:

  1. TEMPERATURE RATING: Put simply, these are the temperatures at which you should be able to get a night's sleep in normal circumstances. For fuller details about the TOT rating see this Technical Briefing.
  2. LINERS: A liner will add to the insulation, but as always there is a trade-off between the extra weight and bulk, and the warmth you gain. Silk liners add roughly 2°C but only weigh around 140g so they’re a popular choice. If you’re particularly concerned about cold, our K Series Filler Bag is 100g heavier than that but will add 10°C.
  3. CLOTHING: Thermal baselayers obviously help to keep you warm, and lightweight warm layers such as our Wafer clothing boost the performance of the bag considerably. See the Clothing section below for more details.
  4. FABRIC OPTIONS: Our M Degree bags come with 7X outer fabric as standard: a mini-ripstop nylon with excellent tear-strength. They are also available in Hypershell, which is highly wind/water resistant but only adds about 15g to the total weight. These bags are also available with a waterproof footbag (racing tents can be pretty cramped and it’s easy to end up sleeping with feet pressed against wet fabric) that can be ordered either permanently fixed in place or detachable to allow stripping down for ultralight overnights.
  5. ZIPS: Zips are an option, but most competitors don’t ask for one. A short zip with draft tube adds about 50gm (2oz). A full zip and draft tube adds about 110gm (4oz). Zips also add to the packed size. A further option is the foot zip which only adds about 10g (⅓ oz).  

Clothing selection

The kit list specifies a warm mid layer, for cold days or at camp in the evening. The Wafer Ultima Jacket or Pullover provides warmth down to round about freezing point, but weighs just 185g (155g for the Pullover); if you really tend to feel the cold though, then the Ultra K Jacket or Pullover have also proved popular on the Fire & Ice, offering a fantastic level of warmth and still a very low weight: they have a TOT of -5°C but are nevertheless just 240g or 225g respectively.

Some opt to take a light synthetic gilet too. Like the Wafer clothing, the Sigma Vest has a TOT of 0°C but, thanks to its synthetic Primaloft insulation, it’s far less moisture sensitive than down: you can wear it to boost core body warmth when running in the cold without being concerned about perspiration saturating it.

All the above clothing can be worn inside a sleeping bag on colder nights; if Wafer Trousers and Wafer Socks are also worn to create a Sleep System, the performance will be quite significantly enhanced, despite a weight gain of only 175g. A full set of Wafer clothing (jacket, trousers and socks) will add 5°C to the temperature rating of your sleeping bag and, when you wriggle out of your sleeping bag in the morning (or the night), you will experience far less of a temperature drop to shock your system!  And please, don’t underestimate the importance of the down socks! Cold feet are a quick and simple way to an uncomfortable, interrupted night (and a sluggish, groggy next day).

The next Fire & Ice Ultra starts on 26 August 2024:

Photo by Paul Morris.