This trick is also commonly referred to as 'Blind Snowboarding' due to the fact the fog effect never disappears while your snowboarding. By voiding out far enough down towards the snowboarding track the game will spawn you as if you just failed snowboarding which is within yeto's text trigger and hence skips the Snowpeak Mountain portal.
You can do this on either side but is easier and faster on the right side. Roll to the corner of land shown in the video as close to the edge as possible without triggering the Portal CS, then LJA along side the wall and you will bypass the warp point. If you are slow at aiming the keese might try and attack you, in which case step back away from the portal trigger and then slash them, if you spin attack you will move forward and most likely hit the portal trigger.
It saves ~24 seconds to skip the portal. It is important to know that you will not be able to see a lot because the fog effect never goes away until you beat the portal so you will need to remember the turns of the shortcut.
As against TP for the gamecube rupees do spawn during blind snowboarding (95 R) which can be useful to skip the two Snowpeak Ruins rupees in an Any% run.
Right after snowboarding there is a big Midna trigger on the ground making her pop up and talk to Link about Snowpeak Ruins.
This trigger can be bypassed by using two jump attacks with a rather precise angle on either side of the trigger with the right side being the easier one.