Have Portable Fans for Bouldering Become Mainstream?

April 21, 2026

Adam Ondra sitting in front a cordless fan during his bouldering session for Emotional Landscape 8C/V15, Photo byMartin Švec

The short versionBetween February 2025 and March 2026, Adam Ondra sent his first V17 and flashed four separate 8C boulders, becoming the only person on earth to flash 8C more than once. One more thing seems to appear consistent, a portable fan. In this article we will go deep dive into the science behind why we seeing fans everywhere at the crag.

Have Bouldering Fans Gone Mainstream? Adam Ondra Says. F* the fan, it is cheating!**

At some point the numbers stop being impressive in a conventional sense and start being almost incomprehensible. Adam Ondra is the G.O.A.T and he just keep proving it.

But the grade isn't the whole story. Watch the sessions closely, in almost all of them, you are seeing a new tool that started appearing post his V17 send. A cordless industrial fan, likes of Makita, Milwaukee or Ryobi.

Seeing his reaction video just tells you how much of an impact influencing the condition has for peak bouldering.

February 2025: V17 at Fontainebleau

Soudain Seul, "Suddenly Alone" is a low-start extension into the V15 Big Island at Fontainebleau. First put up by Lorenzi after roughly 25 sessions, the grade was proposed at V17 (Font 9A), making it one of the first of its kind. When Ondra arrived, he gave it five days total. On the third try of the fifth day, he sent it.

His own words: "It felt like the hardest problem I had ever done."

The moment we noticed

As he was on his send go, 3 things were in the camera frame. The rock, Adam and a Makita fan. It is not there for the breeze, it is there to help create better friction, and give the best climbing condition for this send-go.

February–March 2026: Three 8C flashes in two weeks

In the space of two weeks, Ondra flashed three separate 8C boulders at three different locations: Lion's Share in Brione, Celestite in Val Bavona, and Emotional Landscapes in Maltatal, Austria. That's his third, fourth, and fifth 8C-level flash, making him the only climber in history to have done it more than once, let alone four times.

AOA Notable records: 2025–2026

Soudain SeulFontainebleau, France · Feb 20254th ascentV17 / 9A
Foundation EdgeFionnay, Switzerland · Nov 2025Flash8C / V15
Lion's ShareBrione, Switzerland · Feb 2026Flash8C / V15
CelestiteVal Bavona, Switzerland · Feb 2026Flash8C / V15
Emotional LandscapesMaltatal, Austria · 11 Mar 2026Flash8C / V15

▶ Watch — 3× 8C / V15 Flash in 2 Weeks | Adam Ondra

What we keep seeing

Across all of these sessions, one thing is consistent besides the grade. There is almost always a fan somewhere in the corner or on a ladder. Every problem. Every session.

"When you climb at the highest, every variable matters. Temperature, moisture, chalk build-up. Any one of them is the difference between a flash or a fall."

The science

Why fans work: the physics of friction at the limit

Skin friction and moisture

Dry, slightly hardened skin has a significantly higher coefficient of friction against rock than moist or sweaty skin. Chalk works precisely because it absorbs surface moisture and stiffens the skin. But chalk residue from previous attempts builds up on the hold itself, creating a glassy layer that actively reduces grip.

Humidity and Rock

Even without visible sweat, ambient humidity transfers to rock surfaces. On polished outdoor granite or limestone the difference between grippy and glassy can be a matter of a few percent relative humidity. A fan doesn't change the outdoor climate, but it does control the micro-environment at the hold itself in the seconds before you commit to it.

It's not just the GOAT: how fans became a standard kit

Over the past few years, portable fans and jet-fans have quietly become standard equipment among climbers working at their limit outdoors. Gripped Magazine's 2022 bouldering fan roundup captured the moment when the broader community started formalising this.

The question has shifted from "does it work?" to "which one should I use?"

Why it matters on a flash attempt

On a flash, you pull on cold — with no prior touch to calibrate the hold's condition. This is precisely why fans matter most on flash attempts: you're relying entirely on the hold being in its optimal state when you first contact it.

Big fans vs jet fans, two different tools

The key difference: A large jobsite fan moves a high volume of air over a wide area — excellent for ambient airflow and cooling your body between burns. A jet fan delivers concentrated, high-velocity air onto a very small surface area — all of it focused on a single hold. Neither replaces the other. A large fan changes the environment. A jet fan prepares the specific hold.

The conclusion

Correlation or coincidence?

Ondra sent these problems because he is Adam Ondra. The gap between him and everyone else is huge. But the fan is present across every single one of these sessions, on four different problems, in five different locations, over more than a year of climbing.

The science is real. The community adoption is real. We'll let you decide if this is aid or not.

Where ChalkBlaster fits

ChalkBlaster is not a replacement for an industrial cordless fan, it's a different tool for a different job. It's compact, USB-C charged, and designed to go everywhere your chalk bag goes. The most compact solution with multiple use cases.

The portable solution for targeted hold prep.

ChalkBlaster, 130,000 RPM jet airflow. Boar or nylon bristles. USB-C charged. Fits in your pack. Built in Denmark.

See the ChalkBlaster →

Sources: Adam Ondra — Soudain Seul 9A · Foundation Edge 8C Flash · Emotional Landscapes 8C Flash · Baffle Days — Review: The best fan for rock climbing (YouTube) · Adam Ondra on YouTube