To clarify my statement above:

Closure occurs every winter season.

Additional restrictions are in place for the particular area on the linked map. Although your plans are to stay on numbered forest roads, you have to assume a violation of a closure order with the addition of the designation of the area as sensitive will bring heat.

You may think you can stay on top of the snow, but that does not qualify you as an exempt class, as an SUV is not an over-the-snow vehicle. Traveling in a line, later vehicles will almost certainly reach the ground through the snow. And a ranger wouldn't buy the explanation, anyway.

I was through that area yesterday. There's a reason they don't want people on anything but the numbered trails in that area...it gets torn up fast and leaves serious damage.

John B.