Derborence

Distance: 24.9 miles. Elevation: 3356 ft.

Today's destination was Lac de Derborence, at the end of the valley of the same name. The area is a protected nature reserve. I left at just before noon, heading in the same direction as yesterday's ride until I reached Eide, at which point I headed west towards Derborence. I made several reports onto my phone during the ride as usual. Weather was hot and sunny.

12:31 Well if I thought yesterday was hot, today is even hotter. I've stopped at the same picnic bench as yesterday, which comes after just four miles, but the climb to here is really steep and completely exposed to the sun. I'm not wearing a base layer today but I am still carrying my backpack with my drone etc. This time I'm going to top-up my bidon at this water trough.

At least this time I knew what to expect, although it was still somewhat surprisingly steep. All done in second gear. Temperatures today are supposed to reach 28 or 29°C later so I'm glad that (I think) most of this ride further up is through forests which I don't normally like but at least you get some shade.

13:29 Just as I got on my bike to cross the road to begin the climb again after that last report I realised I had a flat tyre on the front. Luckily I had the shade and the picnic bench to sort it out. So I proceeded to get the tube out of the tyre but I couldn't pump it up enough to see where the puncture was, so I decided to chance using one of my lightweight Chinese inner tubes that I've been carrying with me for ages but never used. That proved a bit tricky to pump up because the valve wasn't always seating on the pump properly, but in the end I got it pumped up to a reasonable amount. The tyre wasn't fully seated on the rim but that's normal with these 35mm tyres, with just a mini-pump to hand, so I wasn't too bothered.

So I set off and the front is rolling unevenly with a slight lump in the tyre at one spot. It's a bit uneven and that's okay when you're going slow but on the couple of bits where I was on the flat going faster I realised the front wheel was bumping up and down quite a bit, so I'm not sure what it'll be like on the descent later. I'll probably have to take it very slowly. I've now stopped in the first bit of shade I've seen. I'm about two and a half miles further on from that last stop and it's been extremely steep - first gear nearly all the time and always in the sun, so it's been a real struggle so far. Hopefully I'll get some shade soon or easier gradients. I've just finished my banana.

This is the section (in purple) since the last report. Average gradient of over 8%, but that includes flat bits! The section I'm on now is 12%, and hasn't finished yet!

15:09 After that last report the road stopped zig-zagging in its way up the side of the mountain and leveled out to turn north into the mountains, along the edge of a deep valley.

So it was much cooler and easier. I stopped at one point and got my drone out and took some aerial photography but I was very wary having not had much practice lately, and I didn't want to take it too high nor too far, so that was a bit nerve-racking. UPDATE: When I got back after the ride, I realised that due to operator error, I had not recorded any video from the drone - Doh!

After that came the most amazing series of tunnels or maybe it was just one tunnel with different 'windows' in it. I couldn't stop stopping for photos.

Shortly after the tunnel the road appeared to have reached the end of the gorge and entered into a mixture of pasture and woods and rocks.

Very pleasant. There were walkers here and there. I've only seen a couple of cyclists today. The road ahead looked like wall-to-wall mountains all around and as usual it was difficult to see how the road was going to get out of it, but then it started climbing steeply and I came to a junction where Derborence was to the left, and I'm still climbing now. I saw a sign saying I had 3.2 km to go. That's two miles, so about half an hour or slightly more at this slow pace I'm doing. So I've stopped here in some shade mainly to transfer some money to my son who's just sent me a message on my phone, but also to have a couple of painkillers even though I haven't felt particularly the effects of the sun yet but surely will do. Also I'm going to have an energy gel, knowing there's not long to go but I'm feeling low on energy so I'll press on now. My front tyre still appears to be pumped up fully so that's a good bit of news.

15:34 Well the energy gel trick worked as usual and there wasn't very far to go after that last stop, and the road even descended for quite a long way so that was another wasted energy gel! I've arrived at the lake. There's quite a few people here parked in the car park. The road to the lake was gravel for quite a long way, so it's a good job I'm on my gravel bike.

I walked the bike down to the lake, took a few photos and then started riding it to further along, but a park ranger stopped me and told me I wasn't allowed to ride here because it's a protected area. That was ok by me and I completely understood. We had a bit of a chat and I told her that she was very lucky to have a job that involved walking around these beautiful surroundings. She knew it! I also learned that Swiss french is similar to French french, whereas Swiss german is difficult for germans to understand.

I'm a bit wary about being by this lake in case there are any mosquitoes or anything. I haven't heard or seen any. All I can hear is grasshoppers and other insects and it's very peaceful.

Protected natural site DERBORENCE

The exceptional alpine landscape of Derborence was shaped by the two gigantic landslides of the 18th century that created the lake. Glaciers and watercourses formed this deep valley and the imposing walls of the Diablerets. To the south of the lake is one of the last primary mountain forests in Switzerland. This area is home to many natural resources, such as centuries-old fir trees, three-toed woodpeckers and black salamanders, and is regularly flown over by the bearded vulture.

Dogs on a leash, Do not leave the paths, Take your rubbish with you

Capture prohibited, Pick-up prohibited, Mushroom picking prohibited
Camping prohibited, Caravanning prohibited, Scale models or drones prohibited, Fires prohibited, Swimming prohibited, Navigation prohibited

Derborence is one of the largest nature reserves in the Valais section.
On 30 March 1961, the State Council declared the virgin forest, Lake Derborence and the area to the north-east a "protected site" and an "absolute reserve of fauna and flora".

Final report at end of ride At the lake I'd noticed that my front tyre looked more even around the rim, so I spun it round and it was completely even all round, so somewhere on the climb it must have popped onto the rim. Excellent. I didn't know that was a thing.

I dutifully walked my bike back through the woods from the lake shore to the car park.

I really enjoyed the descent, initially through the sparse woods, then on the gorge road and back through the tunnel.

At one point I was astounded at the depth of the gorge so I got off my bike to video it while walking along to try to provide a sense of the scale of it.

Obviously on the way back I stopped for loads of photos/videos. The tunnel(s) fascinated me once again.

Three of the tunnel 'portals' visible here

There was nothing further to report other than that the front tyre was totally OK. The top of the descent was warm enough to not have sleeves or rain jacket and towards Conthey it felt like I was riding into an oven. Really hot. Wahoo recorded 28°C, and that included the wind chill from moving. For the steep descent into Conthey there was a very strong headwind, which is not very nice on main roads - lucky it wasn't gusting from the side.

Ride Notes

Good The lightweight inner tube had worked fine, except the slight problem inflating. I had to make sure the pump was aligned with the valve otherwise no air was going in.

Good I made the effort to fly my drone

Good The front tyre had magically 'popped' back onto the rim. Thinking about this later, it could have been due to (the inverse of) the bidon effect (see below).

Bad Got a puncture - I never did find out what had caused it, but repaired the tube and put it back on the rim after the ride.

Bad I discovered later that the drone video fiasco was my fault. I was so out of practice. I thought the button to toggle between stills and video was actually the 'start recording video' button! (I have since RTFM). So I had been flying around an amazing gorge thinking I'm capturing it, and then landed and turned the video off (I thought), which actually started the video! So I have about 3 seconds of shots of the ground and my hands. Another excuse I have is that I could barely see anything on my phone under the blazing sun - a VR headset or somesuch would surely be a boon. Until the time when they can project a heads-up display directly into your occipital lobe, we're doomed to struggle with displays under strong sunlight....

Bad After the ride I noticed that my empty bidon had 'collapsed'.

Obviously the sticky energy drink had formed an airtight seal, and I'd left it closed at the top of the ride, so the increase in pressure coming down from higher elevation had pushed the sides in. I managed to restore its shape by pushing the sides out with a wooden spoon and then blowing as much air as I could into it and quickly sealing the valve. After a few hours and several more 'inflations' it was back to normal. Lesson: leave your empty bidon valve open before the descent. A day or so after the ride it occured to me that the inverse of this effect (ie outside pressure decreasing at a higher altitude) could explain why my tyre had popped back onto the rim during the ascent. I'm glad I'd paid attention in the physics lessons at school!

Interesting I just discovered there's a film called Derborence (1987) based on the book of the same name, inspired by the two huge landslides that formed the lake.