NOAA’s ENSO blog maps the impact of El Niño on snowfall in North America.
Obviously, snowfall is limited in its southernmost reaches because it needs to be cold enough to snow, so the effects are strongest in the higher and colder elevations of the West. To the north, however, there is a reduction in snowfall (brown shading), especially around the Great Lakes, interior New England, the northern Rockies and Pacific Northwest, extending through far western Canada, and over most of Alaska. In fact, El Niño appears to be the great snowfall suppressor over most of North America.
The above map shows the change in snowfall during all El Niño years; additional maps tease out other details (such as the difference in moderate-to-strong El Niños). [CNN]