Contracts of employment generally deal with this as a misconduct matter. However, starting a disciplinary procedure under these circumstances is likely to land the employer up in an employment tribunal where they would look at whether the disciplining was a "reasonable response" to their absence. This is unlikely to be the case.
So what are the options. One thing you are unlikely to be able to do is to force employees to take the time off as part of their annual leave. Unless you give appropriate notice to employees you can't force them to take holiday. The notice that is required is twice as many days as you are wanting them to take. So if a week is lost because of the disturbance then you would have been required to give two weeks notice. Not possible in the current circumstances.
One of the teaching unions has said today that failing to pay teachers who are not able to get to work would be an unlawful deduction from wages. This may be true for the members of that union if they have collective agreements in place, but it is not true for those not protected by such contractual or collective agreements.
Earlier in the week the BBC reported that the NASUWT teaching union were warning that one local authority planned to dock pay from absent teachers. Chris Keates, the General Secretary of the NASUWT said "Employers should be warned that they are vulnerable to a legal challenge for unlawful deduction of salary if they seek to penalise teachers in this way."
In the absence of prior agreements on what happens in this scenario the course of action are limited.
- Unpaid leave. Employers have no obligation to pay employees if they are not at work unless they are sick or on holiday.
- Using unused holiday entitlement. If an employee still has annual leave left you can offer them the opportunity to take the time as holiday. The qualification on notice does not apply if it is by mutual agreement.
- Flexible working. If you do have a flexible working system in place you can allow the employee to make up time later.
- Working abroad. If it is possible you can allow employees to work from wherever they are stranded.
A practical solution and the most reasonable response may be to offer an employee some or all of the above options above, letting them choose which one to take.