Here is how I do my snow-dyeing.
First I soak the fabric in a soda ash solution (9T soda ash dissolved in a gallon of warm water) for about half an hour. (The soda ash solution can be saved and used again, so I store it in a recycled cat litter bucket with a handle and lid.)
Next, I wring out the extra solution and manipulate the fabric as you choose. In this case, I picked each yard-long piece up by a corner and kind of squished it into a rope. One piece I accordion folded, the other I coiled. I put them into the container:
I found plastic baskets at the dollar store that just fit inside the dishpans (also bought at the dollar store) that I use for various dying tasks. Using the basket means that the fabric will not sit in the dye and melted snow solution, and results in different patterning.
I pack snow on top of the fabric, and leave it outside overnight so the fabric can freeze.
The next day, I mix up my dyes (more on this to come) and bring the prepared fabric into the house. I put it into a black garbage bag to keep any snow that escapes contained (and also so I can make sure my cats don’t get into it!) and apply the dye.
I let the snow melt, and then rinse out the fabric. In this case, the fabric sat about 18 hours. I did all the preparation one afternoon, and when I got up the next morning the snow had all melted.
Here are the two pieces that resulted from this session. The first is the one that was coiled, the second the one that was accordion-folded. I was a little disappointed in the amount of fabric that remained undyed this time, but the unpredictability is part of the magic of this process.