Unless your contract of employment states otherwise, you do not have to pay staff who are unable to make it into work because of bad weather. However, if you have to close your business due to bad weather and, therefore, cannot provide your staff with work, you may have to pay them.
Of course, if employees do not come to work when the Met Office has officially warned against travelling, it puts employers in a difficult position. You don't want to be seen to be pressurising employees into putting themselves at risk.
An added complication is when schools close. Employees have the statutory right to take time off work (unpaid) in this situation to look after their children. If you decide to pay employees who are unable to come into work due to the snow, but not to pay those who take time off because their children can't go to school you could find yourself facing a claim of less favourable treatment.
Most employers will find a workaround in these circumstances which may be to allow some home-working, to let staff use their holiday entitlement, or to have paid time off and make the time up later on. However, for larger employers or those who have found the recent bad weather particularly difficult to manage, it may be best to formulate a policy to cover this issue.
If you would like help with such a policy or would like to discuss this issue further, please contact me.