Hello, I’m Kyon. I’m quite the "rain magnet"—so much so that I often get caught in the rain with alarming frequency. My middle school graduation was rainy, my high school field trip was hit by a typhoon, and it seems like rain is just part of every event I attend. Even in the mountains, the probability of rain is high, and I’ve often been forced into hikes that felt more like ascetic training.
Among all those, if I had to choose the most memorable rainy mountain trek...
It was about six years ago, during my very first tent-stay trek. I was carrying an unfamiliar, heavy backpack, traversing from Mt. Goryu to Mt. Kashima-yari over three days and two nights. I knew the weather was taking a turn for the worse, but it deteriorated much faster than expected. Early on the second day, I faced harsh conditions with heavy rain and strong winds as I crossed the Hachimine Kiret, the most challenging part of the trip. The rain-soaked rocks were incredibly slippery, and it was a continuous stretch of chain-assisted paths and ladders. The wind was so strong that at times I couldn't even walk without bracing against it.
I remember desperately hiking for about seven hours in those conditions, unable to take a break while battling hunger and cold. My rain gear was soaked through, my shoes were sloshing with water, and even though I had a rain cover on my pack, it was drenched. I was worried about whether my gear inside had gotten wet, but when I arrived at the Tsumetai-ike Sanso mountain hut where I was staying and opened my bag, everything inside was perfectly dry.
What I was using at the time was a dry sack.
As someone who gets caught in the rain so often, I use dry sacks whenever I go to the mountains or ride my bike.
Some of you might think, "Why go through the trouble of using something expensive? Isn't it enough to just put things in a plastic bag for waterproofing?"
The big difference from a plastic bag
It's true that a plastic bag can serve as a decent waterproofing tool, but there are major reasons for using a dry sack.
Plastic bags can be a hassle to open and close once tied, they tear easily, and if you don't notice a hole, your gear will get wet. Another drawback is that the bag itself just becomes trash later.
With a dry sack, you just roll the top about three times and snap the buckle shut; being able to open and close it easily is a real advantage.
Also, I often stay in tents in the mountains, and during busy times, your tent can be right next to someone else's, where you can hear every sound. Everyone has different bedtimes and departure times, and it’s often very unpleasant when someone is crinkling plastic bags while you’re trying to sleep. This is especially true in shared mountain huts, so I use dry sacks partly out of consideration for those around me.
Helpful when packing
For someone like me who isn't great at organizing, using separate dry sacks makes it immediately obvious where everything is. This applies to bikepacking as well; I find them extremely useful for packing efficiently and neatly while balancing limited bag capacity.
Other ways to use them
When I go on overnight mountain trips, I put soft items like clothes into a dry sack and use it as a pillow. They are also super handy when heading to an onsen, a river, or the beach, because you can put your wet gear inside so it doesn't soak the rest of your belongings.
There are many types and sizes of dry sacks, and at Circles, we carry fully waterproof dry sacks from SEAL LINE and ORTLIEB.
【SEAL LINE】
Blocker Lite Dry Sack
Price : ¥2,200-(excluding tax)
Color : Blue , Coral , Orange , Yellow
Capacity：2.5L
Weight： 28g
SEAL LINE uses 20D nylon with a PU coating, featuring a block shape that makes it easy to pack and lightweight.
【ORTLIEB】
Dry Bag PS10
Price : ¥2,300 ~ ¥3,300- (excluding tax)
Color : Black , Dark Grey , Light Grey , Olive , Orange , Light Green
Capacity / Weight： 3L / 38g , 7L / 54g , 12L / 70g , 22L / 104g
ORTLIEB is a dry bag that uses an ultralight nylon fabric called PS10. The inside of the bag is PU-coated, while the exterior retains the smooth nylon texture, which creates less friction and makes it easier to pull things in and out.
【ORTLIEB】
Dry Bag PS10 with Valve
Price : ¥3,300~¥4,000_(excluding tax)
Color : Dark Grey , Light Grey , Orange , Light Green
Capacity /Weight：7L / 58g , 12L / 74g , 22L / 108g
This is a model of the aforementioned Dry Bag PS10 with a valve added. It allows you to vent air from inside smoothly, making it possible to compress the bag further even after closing the top.
I also recommend the PAPERSKY Water Proof Pouch – Speedo Sack, which is convenient for storing small items.
【PAPERSKY】
Water Proof Pouch – Speedo Sack
Price : S / ¥2,200- , M / ¥2,450- (excluding tax)
Though they are a bit expensive, I definitely want you to use them for things that you absolutely cannot let get wet. They are also great for everyday rain protection, not just for mountains or cycling. Please give them a try.