Lake Sonoma 100k

October 2023 ยท 7 minute read


I ran the Lake Sonoma 100k on October 21, 2023 in a time of 11:47:02. My time was good for 8th overall.

Race Summary

Lake Sonoma is a beautiful, but tough, place to run a race. The trails certainly live up to the “relentless” motto of the race. In the October fall, much of the course was covered in a layer of oak leaves. I went skiing on acorns a few times, but managed somehow to stay upright for the entire day.

The course follows the same trails as the famed Lake Sonoma 50, which occurs in April of every year. The additional 12 miles are tacked on at the beginning and mid-sections. On paper, the course claims nearly 14,000 ft of climbing; however, this isn’t split up into big climbs. Runners are always going uphill or downhill, without any sustained flat relief.

The weather was ideal for our race day but the morning after, my wife and I were packing out our camp in a steady rain. We had camped at one of the boat-in sites on the lake, something that I thought was really fun and would totally do again. Although, hiking out of your camp at 4am as a warm-up isn’t advised for optimal performance in a 100k race!


Things that went well:

Things that could be improved on:


This race was the first time that I’ve used Scratch Labs products for my entire nutrition strategy. The high-carb mix and regular mix, when a serving is combined, offer 280 calories of mixed sugars plus over 500mg of Sodium. I combined the two servings into a 600ml flask and it was a bit thick/sludgy for about 5-10 minutes until the clumps of drink mix dissolved. I would definitely use this combined recipe again, but probably reduce the amount of regular Scratch by 20-30% to help the solubility, plus reduce the salt content. I felt like the mix was just a tad heavy on sodium for my liking.

I ate 3 or maybe 4 packets of scratch chews during the whole race, whenever I felt like I wanted to chew on something. My calories came mostly from the drink mix. I drank one of my 600ml superconcentrated bottles every 60-90 minutes. For the longer sections between aid, I carried a second bottle. I was also drinking water according to my thirst.

The energy level that I received from this strategy was a steady output and I never had serious cramping issues. I did feel a bit nauseous by the end, but I think this was mostly from the taste of the mixture since it was the exact same thing for nearly 12 hours.

Race Execution

Going into the race, I had a split plan from I’ve been using UltraPacer for a few years now and I find that it’s incredibly accurate for me. My build-up to a target race includes many easy runs on similar terrain - in this case, I knew that my average “easy” low-zone-2 effort on similarly-steep terrain would average out to roughly 10 minutes per mile. I use UltraPacer to create a plan where my first 20 miles is roughly 10 minutes per mile, then there’s a linear fall-off after that point as my body gets exhausted.

My plan on ultrapacer had me finishing in roughly 11 hours 30 minutes. I took a wrong turn early in the race, added nearly a mile, and finished 17 minutes slower than plan. That’s a really good prediction!

I did screw up my race execution after the wrong turn. All of a sudden, I found myself going from top-50 position to being in the back half of the pack at mile 3. I let myself get into way too high of an effort zone (well into zone 3, marathon-level effort) for a few miles as I tried to regain position in the field. I did chill out after mile 7, but I have no doubt that those wreckless miles from 3-7 took away from my potential to do better for the day.

However, at the end of the day, going too hard for 45 minutes doesn’t ruin the chance for a good ultra performance. After I cooled my nerves, I executed the race pretty much according to plan.

I did find myself feeling really good around mile 35-40, so I pushed the pace for about an hour (or at least I thought I was pushing the pace). I quickly got tired and realized around mile 45 that I was going to struggle to maintain the same effort for the rest of the day. So, I focused on consistency from that point on. The focus paid off.


I wore the Nike Ultrafly and it was a fantastic shoe choice for the dry varied-surface trails. I started in a t-shirt but finished in my SFRC race singlet. I wore Tracksmith short tights, which are my go-to for long races. Lastly, I used a Naked band to hold my 1-2 soft flasks around my waist for the race. I find that I like the waist belts more than vests when carrying less than 1L and minimal layers.

Final Comments

I was happy with my performance, and extremely happy with the consistent execution given that this was my first return to the ultramarathon distance in a couple of years.

I had introduced a lot of extra complexity for the weekend by choosing to camp on the lake for the nights before and after the race. In these circumstances, it makes me that much more proud of the performance. I had dropped my wife off with her kayak at the boat dock on Friday afternoon, and I hiked in the rest of our gear to our campsite on the lake. It made for a fun and memorable weekend, but it also meant that I had a 3am wakeup on the morning of the race in order to give myself time to get ready, hike out, and drive to the start. I also had to get back to camp and take care of myself after the race without having access to all the first-world comforts that we usually have access to after a big race effort.

It rained a lot on the night after the race. Packing up a soggy camp, with post-100k legs, and hiking up 500+ vertical feet with a 40-lb load is one way to force some active recovery!

One last entertaining anecdote

When I got to the start of the race, as I looked to my left and right at the competition, I noticed a guy who was wearing a singlet, 1-inch splits with the Michigan logo, and a headlamp, with a flattened plastic water bottle tucked into the back of his headlamp strap.

Chris lined up at the start line, smiling and looking to his left

Amused at Geoffrey Burns' unconventional hydration strategy - a recycled plastic water bottle, flattened, tucked into his headlamp strap. Burns went on to win the race in 9:35.

You don’t see many good ultra runners showing up to the start of a 100k race with 1-inch splits, or a hydration strategy that includes a 16oz flattened Crystal Geyser bottle that looks like it was dug out of a trash can. I couldn’t help but think that this guy’s day was going to play out in one of two ways:

  1. he’d blitz the course and win the race
  2. he’d blow up spectacularly after leading for several hours

Turns out, he blitzed the course and won the race. His name is Geoffrey Burns, member of team USA for the IAU 100k world championships. He ran the course in 9 hrs, 35 mins. In splits. With a recycled plastic water bottle. Very impressive!