Shadowslice Snow Columns is a speedsolving method that was proposed in 2015 by Joseph Briggs and Julien Adam.
It is has been described as variation of many methods, including Columns, hence why it's in this website.
It takes around 50 algorithms to solve with it and it averages around 50 moves.
Here's an overview of the advanced version:
STEP 1: EOedge
It's just like EOline, but instead of solving DF and DB you solve FL and BL edges.
Step 2: orient corners
As you do that make sure you get white corners in the first layer and yellow corners in the last layer as you solve the E layer.
Step 3: Solve corners
There are quite some ways to do so.
Step 4: LEE
Solve the Last Eight Edges.
There are plenty of SSC variations that you can find in the speedsolving wiki. As you can see, the method looks like Columns in the third step, an advanced belt method variation by step two, and is overall an orient first variation. So many principles combined into one signle method...