Iditarod Invitational

Iditarod Trail Invitational

The Iditarod Trail Invitational is the most remote and longest winter ultra marathon in the world, taking place in February or March every year. Competitors can travel by bike or ski, or can even run the 350 or 1100 mile courses. The route travels close to the famous Iditarod dog sled trail from Knik, Alaska to McRath or Nome. The maximum time allowed is 10 days for the 350, and 30 days for the 1100 mile races. Race records are in the 3-day and 15-day area respectively. Snowmobiles attempt to break trail for the lead racers. Experience in high-altitude mountaineering or polar expeditions is necessary and qualifying races are required. There are no prizes to the winners, but the satisfaction of completing the race has its own personal satisfaction.


Sleeping Bag Choice

The challenge in deciding which sleeping bag to select is in finding the required warmth at the lightest possible weight. We'd suggest the Hispar 1000 and the Xero 1000. The Hispar is top of its class for lightness. The Xero is a bigger bag that will accommodate you in your down clothing. The Xero also has a down-filled gusset behind the half-length zip, and water-resistant fabric at the head and foot area. A third option is the Diamir 900 K filled with our unique 1000 fill power down.

To maintain your sleeping bag's performance the VBL should be considered.

The basic figures for the recommended models:

S-bag TOT (Min Temp) Weight Packed size
Hght x Diam (cm)
F gm oz 
Hispar 1000 -46 -51 1520 54 49 x 27
Xero 1000 -38 -36 1860 66 44 x 25
Diamir 900 K -32 -26 1570 55 44 x 25


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: To maintain your sleeping bag's performance a Vapour Barrier Liner (VBL) should be considered.
  3. CLOTHING: Down clothing is an excellent way to improve insulation by layering up while asleep. The Yukon Jacket or the Hispar Jacket are both ideal lightweight items to sleep in.
  4. DOWN OPTIONS: The Xero 1000 sleeping bag can also be filled with 950 fill power down (European scale). The same amount of down is put in but the TOT increases significantly.
  5. ZIPS: Full-length zips extend the use of these bags at different temperatures and altitudes. The full-length zip on the Xero bag has double down-filled baffles, replacing the down-filled gusset on the half length zipped version.
  6. PACKED SIZE: PHD stuff sacs tend to be on the loose side. All these bags can be compressed further in your sac.

Figures for Down options:

S-bag Materials TOT (Min Temp) Weight Packed size
Hght x Diam (cm)
F gm oz 
Xero 1000 (950 down) -42 -44 1860 66 44 x 25


Down Clothing Selection

The two down Jackets recommended for the Iditarod Trail Invitational are the Yukon Jacket and the Hispar Jacket. Both are ultra lightweight. The Yukon is specifically designed for racers moving light. If temperatures drop well below the comfort zone, plan to migrate into the sleeping bag. The use of down clothing as a layering system while in your sleeping bag as well as for wearing around camp is a good option.

Other items to consider for your kit list are the Xero Mitts and the Omega Mitts. The Xero mitts are very light, the Omegas more durable and taped for waterproofing. Likewise the Xero socks and Omega socks are extremely lightweight and useful at the overnight stops.

The next Iditarod Trail Invitational begins on February 23, 2025: