With a few specified exceptions, Trip Interruption insurance reimburses nonrefundable prepaid expenses for services that you cannot use, rather than reimbursing new expenses. I would say that your trip has been "disrupted" by Severe Weather, but not "interrupted" as specified in the document. If you do decide to submit a claim I think you will need a letter from the airline explicitly linking the flight cancellation to severe weather, although the fact that the Winter Storm is "named" will be helpful.