The name of a snow runner with three letters could be ski.
sled
winter sprinter
ski
A snow runner can refer to a winter sports enthusiast who enjoys running in snowy conditions, or it can also describe a specialized vehicle or equipment used for traversing snowy terrain, such as a snowmobile or snow groomer.
I suppose 'ski' would fit.
Because u shaddup
I guess if you were to call it something it would be called advancing bases, or if the coaches were talking about the runner it would be called advancing the runner.
A snow tractor is called a sculpture made from snow.
anchor runner
Nothing happens to the batter. The runner who interfered is called out.
The absence of snow is called "snow-free" or "snowless."