I'm astonished that no-one has yet mentioned the most important thing about 'proper' winter/snow tyres. True winter tyres have tread made from a different compound. One of the issues with any normal tyre in winter is that the tread goes hard in the cold so cannot do it's job properly, especially at your lower, winter driving speed. Winter tyres have tread made from a compound that does not go hard in low temperatures so provides MUCH better grip.
However they will overheat if used on dry tarmac at higher speeds and will wear out in no time so are only truly useful if you KNOW that you are going to have snow.
However they will overheat if used on dry tarmac at higher speeds and will wear out in no time so are only truly useful if you KNOW that you are going to have snow.