From The New York Times:

As classrooms become more electronically connected, public schools are the country are exploring whether they can use virtual learning as a practical solution to unpredictable weather, effectively transforming the traditional snow day into a day of instruction. About one-third of school districts in the United States already have significant one-to-one initiatives, where students and teachers are given laptops and can work away from school on some assignments. In New York State, no district can substitute a virtual day for a snow day because not all students have computers or Internet access. In addition to questions of access to technology, in order to make snow days into days of instruction and for students to truly keep up, a thoughtful plan aligned with the curriculum would need to be developed before a storm struck.