Do you have any advice for potential travellers?
Even in mid-March it can be incredibly cold. We had night-time temperatures of -36 degrees Celsius and -25 in the day, which is way below the norm. I managed by wearing all my 4 baselayer and 2 midlayer tops under the outer jacket I was provided with by the clothing store, but I still felt cold at times, and wished I had not left my puffy gilet at the hotel!
I wore marino wool leggings, thick fluffy jogging bottoms and 4way climbing trousers under the salopettes provided by the clothing store, which kept me comfortably warm. When I didn't wear the climbing trousers I felt the cold.
Also, do not leave your Polartec hat at the hotel, believing that the hat provided by the clothing store would be warm enough. I was provided with a synthetic 'fur' hat that was not warm enough, although I managed by wearing my balaclava, hood from my midlayer jumper, and another hat provided by a fellow traveller underneath the 'fur' hat. This was OK.
Bring alcholol disinifectant gel for your hands, as there is nowhere to wash your hands. (In the lodges there are bottles of alcohol liquid, but this I found stung my hands.) The alcohol gel was also invaluable for de-icing my glasses and goggles that kept icing over from the condensation caused by my breath, making it impossible to see. By squirting a bit on the goggles and then rubbing it off with a tissue provided me with about 20 - 30 minutes of clear vision. The only other solution it seems is not to pull the balaclava and neck warmer over your nose, but then your face freezes!
On three nights out of 4 in the forest lodges I woke with a headache, which I later thought might be due to the cold. So on the last night I wore a hat in bed, and woke up headache-free. (After all, people used to wear nightcaps in bed in the past.)
You can buy hand warmers and foot warmers at the hotel if you have forgotten to bring any. I found them invaluable, as they kept my hands and feet warm all day.
I wore silk liner gloves and Polartec gloves under the mittens we were provided with, which were great for when we needed to unclip the dogs' harnesses and for other fine finger movements.
My ankle-high sheepskin slippers were great in the lodges. Flipflops or light weight shoes intended, for walking on rocky riverbeds or shorelines would also have been good for walking on the icey and/or muddy floors between the sauna and changing rooms.