Before all this happened, did you manage to access your original reservation with IB on their system (in manage booking, for example)? If so, did you see it confirmed? Or have you only been relying on the Alaska website to look at your booking?

What's the route? Is it an IB outstation you are departing from, or a Spanish airport? There are major weather disruptions in Spain today, so it could also be that it was a pre-emptive offload to accommodate other travellers?