January has brought a whopping...wait for it...16.5 inches of snow to Alta through January 19. That's not a lot, but many driving through Little, Big, or Parley's canyon got bit by the red snake anyway.
Highway impacts from winter storms depend on several factors. Snowfall amount can matter, but snowfall intensity, pavement temperatures, traffic, timing, and other factors can cause even storms with relatively small totals to cause huge problems.
Twenty-four hour snowfall total in the central Wasatch through this morning are in the 1-3" range. However, most of that snow fell in the late afternoon with relatively high intensity, especially west of the crest, strongly affecting road conditions in the canyons.
The situation at the time was a bit unusual. Winds at mountaintop level (e.g., on Mt. Baldy and at the top of the Snowbird tram) were weak and northerly as we were beginning the transition to the easterly flow that would develop overnight and produce downslope winds along some areas of the Wasatch Front. However, upstream, northwesterly flow was impinging on the Wasatch Range over the Salt Lake Valley. Some light easterlies were observed in the Olympus Cove area, but I suspect this was produced by local outflow from the precipitation area along the west slope of the Wasatch.