You did not mention at what time you would be travelling.
February 16 is a Monday and according to virgintrains.co.uk trains will run at normal times from 16.30hrs.
Recognised rail diversion route is via Sheffield using EM Trains and the Midland Mainline to St Pancras.
But, judging by previous experience (when there have been no Manchester-London Euston trains) these services will be crowded so reservations are essential for the Sheffield-London sector. (Reservations may not be possible for Manchester-Sheffield).
But because of the longer rail journey and the fact that rail engineering works can overrun I would suggest you fly down to London (assuming, of course, that flights will not be disrupted by bad weather).