I feel really awful for your family. It's horrible that the snow and school district are messing up your vacation. I just hope that you and your daughter won't regret your decision to cancel this once in a lifetime trip. I remember being just like her. I used to get so stressed about school and grades. I wanted everything to be perfect, and guess what? I don't feel like it really made any difference in the end. No employer has ever looked at my college GPA. Even colleges didn't really look at my high school GPA more than you are in bracket X. I always felt I had to to have a 4.0 or as close as possible, and in the end, no one but me really cared. Now I look back at all the time I spent studying and worrying, at all the opportunities to spend time with my friends and family that I let pass by, and I wish I had spent less time getting As and more time doing other stuff. A B here or there or even a C, wouldn't have hurt anything in the long run. (I'm not saying let's be cavalier about studying or school, just to realize that every now or then there might be times where something else is more important than a written test) It took me a very long time to learn this lesson.
I'll never forget I went to visit my grandfather and out of the blue he started talking to me about living life to the fullest and making sure if there was something I wanted to do that I did it now. He didn't want me to spend all of my time working and studying and never take time to have fun. He said he and my grandmother always thought they had tomorrow to travel. That they would travel when he retired. Then my grandmother got sick, and they never got the chance. He told me if there was something I wanted to do, I should do it now while I could. He told me you never know what tomorrow will bring. That was the last conversion I ever had with him. He died unexpectedly two weeks later. His death really made it all sink in. It really made me stop and think about where my priorities were. I don't think I'll ever forget that conversation.
So now, when I'm trying to make a decision like yours, I think back to that conversation, and really weigh the pros and cons. Do I feel that missing work, school, or practices will severely impact the family in a big important way? What would be the worst case scenario? A bad final grade? Are the kids grades already high enough that a bad final grade won't really impact anything, maybe take an A to a B. Will this effect scholarships? Or will they remain in the same bracket? Will I be fired or penalized in a long term way for missing work? What are the kids really missing? What will they get out of going? Will they learn valuable life lessons that can't be taught in a classroom? I guarantee that they will remember a big vacation like this for the rest of there lives. What will they remember about the last week of school? School and work will always be there. They never go away. Family time on the other hand is not guaranteed forever. Of course, if it will be too stressful, it won't be any fun.