If an office or workplace is open but a child’s school is closed, or childcare arrangements are disrupted due to snow, employees are legally entitled to take time off.
This is because it's considered an official emergency. It does however remain up to an employer whether an employee gets paid for this or not. Different employers offer different solutions that could include taking the day as annual leave, working from home (full or part day) or an agreement to some flexible working hours.
If practical to do so employers and employees should try and reach an agreement in advance and have it adopted into handbooks and other relevant particulars of employment.