Another variation based on cards you could use is this:
- Create a deck with 1 card for each turn you roughly anticipate the game to last + ~25%
- Add 2 Blizzard cards to the desk and shuffle
- The first one drawn starts the blizzard, the second ends it.
Presto, once it starts, it will not start again and the duration is variable. Let us know how it goes!
Yes that works , I assume you only want the blizzard to last say a maximum of 50% of the game. As JozisTinMan states add 2 Blizzard cards to the desk and shuffle, maybe add 4, 6, 8, it all depends on how long you want the blizzard to last.
Make twenty bits of paper with the stop start option and record how many times you get approximately the blizzard you want. That will give you an idea of what you are after.