A strong El Nino will favor those areas for powder skiing. El Nino tend to invigorate the southerly southern storm track, while weaken our northerly track, hence favoring the snow to our south. Take the El Nino forecast with a grain of salt. El Nino does not rule the atmosphere, but steers snowfall patterns or temperatures towards seasonal tendencies. Your ski day or ski week may be just fine.
Many areas have no tendency at all.
Just watch the weather like normal and that will always pay off for you. A mountain hike in the fall is a rewarding experience. The crowds are gone. The trails are filled with autumn leaves. The leaves are often a collage of colors.