The weather conditions around YVR are a "once in a century" event. Google the news to see how many thousands of people have been delayed for multiple days recently. It may improve by your travel date next Monday, but right now it looks like the storm peak is Friday night or Sat. If that holds true, your chances of traveling as planned rapidly reach 0. Any other year you would not have problems like this, but after seeing what YVR pax have gone through, expect the worst and be prepared. Flooding is likely to disrupt train service even without a big storm at this point (just look at the hydrologic forecast!).