Well the plenary indulgence granted by the Pope for this day had language specific to this:
The indulgence declared by Pope Benedict may be obtained by those who “participate in a sacred function in honor of the Virgin, or at least least offer open testimony of Marian devotion before an image of Mary Immaculate exposed for public veneration, adding the recitation of the Our Father and of the Creed, and some invocation to the Virgin.”
The announcement indicates that those who are ill or otherwise unable to fufill the normal conditions "may obtain a plenary indulgence in their own homes, or wherever they may be, if, with the soul completely removed from any form of sin, and with the intention of observing the aforesaid conditions as soon as possible, they unite themselves in spirit and in desire to the Supreme Pontiff’s intentions in prayer to Mary Immaculate, and recite the Our Father and the Creed."
So it would seem the provision for the mass obligation would be similar - that you honor the day internally, with some sort of devotion (I’d think viewing the mass would help) - but then getting to Mass the first opportunity you get. If the roads are clear tomorrow then go to the morning mass offered…do not wait until Sunday. That’s just my interpretation though.