Ironstone 100K 2027
The forecast arrives five days before the start.
Here you'll find the elevation profile, an estimated finish time based on your UTMB Index and details of the 10 aid stations to plan your nutrition and hydration segment by segment.
What's your time based on your UTMB?
Times estimated by the RAVIT model, learned from real ultra-trail finish times. Enter your UTMB Index (utmb.world) to get a personalized estimate.
Cut-off times and crew - Ironstone 100K · 2027
Data from the official race rules, checked for every edition. The race rules prevail. Positions are interpolated along the GPX track and are a guide, not official course marking.
What you'll find at each aid station
| Product | AS1 Flowing Spring Stationkm 7.6 | AS2 Williamsburg Stationkm 15.6 | AS3 Etna Furnacekm 25.2 | AS4 Alfaratakm 33.4 | AS5 Colerainkm 44.7 | AS6 Indian Stepskm 58.7 | AS7 Jackson Trailkm 68.9 | AS8 Little Flat Towerkm 81.9 | Water Drop - Thickhead Mountainkm 89.6 | AS9 Alan Seegarkm 94.2 |
|---|---|---|---|---|---|---|---|---|---|---|
| Water | available | available | available | available | available | available | available | available | available | available |
| Brand products | available | available | available | available | available | available | available | available | unavailable | available |
La feuille de ton assistance pour Ironstone 100K · 2027
Ton assistance peut te voir à ces postes. Ton plan RAVIT y met tes heures, ce qu'elle te tend et la route pour y aller.
Recto, verso et planche d'étiquettes, en PDF : l'exemple d'une coureuse de l'UTMB.
Elevation profile
The course and its aid stations
Ironstone 100K: times, aid-station stops and fuelling needs by UTMB® Index
Between a UTMB® Index of 500 and 800, the estimated finish time on this race runs from 15h33 to 9h07, and the aid-station stop budget from 0h53 to 0h17. The longer the race, the more stops weigh: this is time you should plan to spend standing still, not only running.
Source
| UTMB® Index | Estimated time | Of which stops | Night hours | Carbs | Fluid | Sodium | Cut-off margin |
|---|---|---|---|---|---|---|---|
| 500 | 15h33 | 0h53 | 8.6 | 933 g | 10.9 L | 7,778 mg | +7h27 |
| 550 | 14h09 | 0h43 | 7.2 | 849 g | 9.9 L | 7,076 mg | +8h51 |
| 600 | 12h47 | 0h35 | 5.8 | 767 g | 8.9 L | 6,391 mg | +10h13 |
| 650 | 11h36 | 0h28 | 4.6 | 696 g | 8.1 L | 5,804 mg | +11h24 |
| 700 | 10h38 | 0h24 | 3.6 | 638 g | 7.4 L | 5,317 mg | +12h22 |
| 750 | 9h49 | 0h20 | 2.8 | 589 g | 6.9 L | 4,906 mg | +13h11 |
| 800 | 9h07 | 0h17 | 2.1 | 547 g | 6.4 L | 4,561 mg | +13h53 |
Figures based on 60 g of carbohydrate, 700 mL of fluid and 500 mg of sodium per hour, "average" preparation and mild conditions (15–25 °C). Above 25 °C, count on roughly 900 mL/h and 700 mg/h. Carbohydrate intake is trained: 60 g/h is a floor, 90 g/h assumes a glucose-fructose blend and a gut used to it.
In the 2027 ranking
Ironstone 100K is 102 km and 2,235 m of elevation gain, that's 124 km-effort: category L, among 87 races in 2027. Its time limit of 23 h requires a minimum speed of 4.4 km/h: rank 42 out of 83 of the widest cut-off times in L.
L ultra-trails 2027: 115 to 154 km-effort
Similar effort in 2027
- Transgrancanaria - Advanced · 124 km-effort
- Quito Trail Ecuador by UTMB® - 80K Oso · 122 km-effort
- LE GRAND TRAIL DE L'OUEST - GTO 85 · 125 km-effort
Other trails worth preparing for
- Pinhoti 100162 km · 3,750 m D+ · October 31, 2026
- Javelina Jundred 100 miler158 km · 1,688 m D+ · October 31, 2026
- Javelina 100k97 km · 1,053 m D+ · October 31, 2026
- Mamba 100161 km · 143 m D+ · November 6, 2026
- Tunnel Hill 5081 km · 182 m D+ · November 7, 2026
- Tunnel Hill 100161 km · 355 m D+ · November 7, 2026
- Mountain Masochist 100k101 km · 3,268 m D+ · November 7, 2026
- Rio Del Lago161 km · 2,697 m D+ · November 7, 2026
- Mountain Masochist 5081 km · 2,311 m D+ · November 7, 2026
Sources and method
- Time projection — times by UTMB Index are taken from the actual splits of runners in each level band on previous editions of this race, aid station stops included. No formula is used as long as these results exist.
- Trail nutrition — hourly targets for carbohydrate, fluid and sodium follow the commonly accepted ultra-endurance guidance. La Clinique du Coureur — Fuelling in trail running
- Course, aid stations and cut-offs — taken from the event's official rules, which prevail in case of any discrepancy. Official site — Ironstone 100K
Weather for Ironstone 100K
The weather for Ironstone 100K will appear here as soon as the forecast models reach that date, around five days before the start: feels-like temperature, rain, snow, wind and storms, section by section and at your passage time.
Detailed weather for Ironstone 100K, hour by hour on the courseFrequently asked questions
How many checkpoints?
Ironstone 100K has 11 checkpoints: 9 aid stations, 1 water point, and 1 checkpoint with undocumented contents. Details are in the two tables above.
What's the longest segment without aid?
The one leading to AS6 Indian Steps: 14.1 km and 200 m elevation gain. That's the one to load up for first.
How do I find the exact location of an aid station?
The Google Maps icon in the “Access” column opens the aid station's location: handy for planning your crew's routes.
What distance and elevation gain?
Ironstone 100K is 102 km long with 2235 m of elevation gain.
How long to finish?
With a UTMB Index of 600 (average runner), the estimated time is around 12h47 for Ironstone 100K.
What's the weather forecast?
The weather for Ironstone 100K will be published on this page around five days before the start, once the forecast models reach the race date. It will be detailed section by section: feels-like temperature, rain, snow, wind and storms.
Want to stack the odds in your favor for Ironstone 100K?
In 2 minutes, RAVIT generates your complete plan: segment-by-segment time, carbs, water and sodium at every aid station, printable roadbook.
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