I have remained open during blizzards and had kids show up. Even one whose parents weren't working. So don't ever assume parents will use common sense If you feel you should close, do so.
Exactly what has happened here! Part of the reason I have been considering a proper policy in the first place!
I don't think I would deduct anything for sending them home due to a power outage as it is beyond my control...but it has never happened, so I'll decide when and if it does! I have also never heard of roads being closed where I live, so it would have to be pretty extreme to consider emergency vehicles not being able to get here or parents not being able to pick up. I guess those of you who live in areas where weather is more extreme have to consider these things more!