Snowfall — ruling 1

This mana is in addition to any mana the Island itself produces, and is blue regardless of what type of mana the Island produces.

Snowfall : règles, fonctionnement et interactions (MTG)

Snowfall is one of those cards players keep asking about. Here is, in plain words, what its official text says, the rulings published by Wizards of the Coast, and the combos players actually run.

Official card text

Cumulative upkeep (At the beginning of your upkeep, put an age counter on this permanent, then sacrifice it unless you pay its upkeep cost for each age counter on it.) Whenever an Island is tapped for mana, its controller may add an additional . If that Island is snow, its controller may add an additional instead. Spend this mana only to pay cumulative upkeep costs.

How it works : Snowfall

Original English text — Wizards of the Coast / Scryfall

#1August 1, 2008· Wizards of the Coast
This mana is in addition to any mana the Island itself produces, and is blue regardless of what type of mana the Island produces.
No other card is named in this ruling.