Contact Eurostar if you're traveling this weekend ---
From the Eurostar website:
Eurostar has cancelled all services on Saturday morning 19 December before 12 noon because of severe weather conditions. People who have booked a journey for Saturday morning are advised not to travel. The rest of the day and into Sunday Eurostar services will be severely disrupted as well. We strongly recommend that travellers whose journey is not essential change their tickets for travel on a later date or have their tickets refunded. Eurostar services should be back to normal on Monday.