With all the snow we have, people often ask why ski resorts don't stay open through April. This story lays out the two reasons.
One: Forest Service permits usually have a closing date on them.
Two: Interest drops dramatically.
Two is probably the main reason. If people still wanted to ski in May, the resorts could convince the Forest Service to let them. But they don't. I'll never understand why people are so eager to ski in November on crowded ice, but are tired of it by April when days are long and warm, and snow is plentiful.
This doesn't apply to backcountry skiers. Their season is just really starting.