How to rescrict everyone's vision?

I will be running a game in which part way through it a blizzard starts up.  How can I restrict everyone's vision to 30 feet? I am really new to APIs so please explain it to me in simple terms.

Hi Richard! 1) Turn on Dynamic Lighting, daylight mode off, explorer mode off. 2) Make sure no tokens emit light. 3) Give everyone's token 30ft of night vision. Depending on the nature of the scenario, you may want to mess around with the Night Vision Effect: Dimming, Nocturnal or None. Of course, areas they cannot see will be black, instead of a blizzard-y white out.

I would add don't put a tint on that night vision, tints don't play nicely together.  We love the idea of tinted night vision to make it more grey, but whilst this works for a player, as DM you will get a horrible effect when the areas of vision overlap.  Nice idea but it is not a priority for Roll20 right now

Thanks for both tips! I have token mod active but am still figuring out how to navigate that.  I can code a in SQL but the roll20 api is still something I need to learn.

There is a great mod calles Dynamic Lighting Tool . After installing it, you can activate it via !dltool in chat, which you can put into a macro that shows up in your bar.

Dynamic Lighting Tool link .