Most people know already that next week is the Ultra Trail du Mont Blanc world series. Most people may not know (or at least I didn’t) that there are actually 8 events part of UTMB week:
UTMB (the granddaddy) - a 176k / 108 mile loop around Mout Blanc, starting and ending in Chamonix
CCC 100k - Courmayeur to Chamonix
OCC 50k - Orsieres to Chamonix
TDS - 150k / 90 miles, also from Courmayeur to Chamonix, but taking a completely different route
PTL - a 300k / 186 mile team-relay for 2-3 people (!!) with barely any overlap of the UTMB course. The PTL is a super fascinating race; someone on Reddit explained it this way:
For those that don’t know, [the PTL] differs hugely compared to usual “alpine and technical” style ultra-marathons.
This is a mountaineering race and you actually have to have mountain leader qualified members in your team of three and mountain skills at a minimum for the other members of the team and have vast mountaineering and multi-day race experience between the group for you to even qualify.
They are sometimes off-trail, there is no route marking and all self-navigated (orienteering), they have to go over glaciers, there are many graded scrambling sections, they do via ferrata on sections, ridge lines, they have a mandatory mountaineering helmet and crampons amongst other mandatory kit, most of the route is above 2500m and well above 3000m in parts.MCC - 40k / 24 miles from Martigny-Combe to Chamonix; “the MCC is a 40 km race reserved primarily for UTMB volunteers, partners and local residents”
ETC - 15 k / 9 miles starting and ending in Courmayuer
YCC - Youth races with three options (4k, 8k, or 15km) starting and ending in Courmayeur (the 15k is the same route as ETC)
So now I know that there are 8 epic races around Mont Blanc that I’ll never get the chance to run. But I can blog about them…
(Like most of my Substack, I’m creating these visuals for my own sake, so I can better understand what’s going on in and around Chamonix. These will end up being very gratuitous; skip this section if you’re not a vert nerd like me.)
I knew there was some overlap of UTMB with CCC, but I never really charted it before.
UTMB starts in Chamonix; CCC starts in Courmayeur; both travel counter-clockwise and end in Chamonix. Approximately 85% of the CCC course uses the same trails as the UTMB (save the climb at the first of the race).
UTMB starts in Chamonix; OCC starts in Orsieres; both travel counter-clockwise and end in Chamonix. However, roughly 40% of the OCC course is run on UTMB trails.
CCC starts in Courmayeur; OCC starts in Orsieres; both travel counter-clockwise and end in Chamonix. Similarly to UTMB vs OCC, roughly 40% of OCC is run on CCC trails (the same shared UTMB-CCC-OCC segment).
OCC starts in Orsieres; MCC starts in Martigny-Combe; both travel counter-clockwise and end in Chamonix. Roughly 60% of the MCC course uses the same trails as OCC.
TDS starts in Courmayeur; UTMB starts in Chamonix; they travel in opposite directions around Mont Blanc, until they both end at Chamonix. However, TDS gives you a unique view of the Mont Blanc region, as it only uses about 20% of the UTMB course trails.
Both TDS and CCC start in Courmayeur, but they travel in opposite directions around Mont Blanc, until they both end at Chamonix. These are very distinct races, sharing approximately 1% of their trails with each other.
Both ETC and YCC are short jaunts around the mountains in Courmayeur. Runners will have an amazing view of the Mont Blanc massif, but won’t actually set foot upon Mont Blanc.
UTMB, TDS, and PTL are fascinating because each are 90+ mile races with very little overlap, but all three end in Chamonix. (76% of UTMB is unique to itself, 77% of TDS is unique to itself, and 90% of PTL is unique to itself; just over 1 mile is shared amongst all three, meaning TDS and PTL only use about 1% of the UTMB trails in their races. Frankly, I’m dumbstruck by how long these races are and how little they overlap with each other.)
But now that I’ve established these races all take place in roughly the same Mont Blanc region, I can collapse my weather charts greatly.
OCC is next Thursday, while CCC and UTMB start next Friday. However, CCC starts at 9:00 AM while UTMB starts at 5:45 PM / 17:45, so really, it makes more sense to look at Saturday for UTMB’s weather forecast, so that’s how I’ll chart weather. But to be brief, Thursday is expected to be fairly warm, with cooler weather coming in Friday and much cooler weather on Saturday, across the board:
Or, imperially:
Note that sometimes I’ll render an aerial heatmap, but I felt here it didn’t really add much information here (e.g. it’s cooler in the mountains, less cool in the valleys) and I already have way too many charts, so I’ll skip the aerial heatmaps for now.
Apologies in advance if my kilometer/mile marker conversion is a bit wonky!
Thursday in the Mont Blanc region is forecasted to be above average, and more in line with 2022 and 2024. Note that the current OCC course records were set in a much cooler year, 2023, by Stian Angermund Francesco Puppi and Toni McCann, respectively.
Or, in imperial units:
Friday is tracking to be a cooler day than Thursday, however 2026 is still forecasted to be a warmer run than 2025. That being said, that the CCC course records were both set in 2022 by Petter Engdahl and Blandine L’Hirondel.
Imperially:
Note that this year’s race weather is more in line with 2022/2023, so perhaps the CCC course records are at risk this year.
As noted above, UTMB starts in Friday evening, meaning that most of the race will be run on Saturday. Therefore I’ll here contrast the Saturday-day weather for this year, compared to prior years. Note that UTMB course records were set in 2023 by Jim Walmsley and 2024 by Katie Schide.
In imperial units:
This year is forecasted to be warmer than last year, but still the 2nd coolest weather in the last five years. Both course records could be broken, though as Katie set the women’s record in a warm year, perhaps the women’s record is more at risk?
No posts
Comments
Nothing yet. Say the first thing.
Sign in to join the conversation.