I hate to say it, but it looks like it is just a dry time of the year for the whole area. I don't think any of the mountains in Washington or BC will be getting much, if any, snow while you are here.
So, driving to other mountains isn't going to result in better snow. However, it could be fun to do a side trip to Whistler since you are so close. If you haven't been there it might be a fun change of pace. You wouldn't do it for better snow, but to just have some fun on two big mountains and even more fun in the village.
It would cost some money and take some time, but it's something to consider if everyone has a passport.