El Colorado and La Parva are, along with Valle Nevado, the three ski resorts that make up the Farellones complex, a little over an hour from Santiago. They're the most practical option for skiing in a single day without planning a longer mountain stay.
El Colorado
El Colorado is historically one of Chile's most traditional resorts, with a base closer to Santiago than Valle Nevado, making it somewhat quicker to reach. It combines beginner runs near the base with more demanding terrain higher up.
La Parva
La Parva has more of a family profile, with weekend homes on the mountain, and a quieter vibe than Valle Nevado. Since it's linked by the Tres Valles pass, it's common to split a day between the three resorts depending on each sector's snow conditions.
All three are covered by the same pass (Tres Valles), though single-resort tickets also exist if the plan is to stick to just one. All three share the same access from Santiago via the road to Farellones.