Heavy snowfall could trigger 10% of the workforce to stay at home, costing the UK economy £320m per day.
Employees are already beginning to ring in sick ahead of predicted snow today (Friday), according to absence management firm FirstCare.
Firms should be braced for snowfall as severe as it was in February this year, where trains grounded to a halt and commuters were forced to stay at home.
Aaron Ross, FirstCare chief executive, said: "We have had a number of employees phone our nurses to open absences starting tomorrow because of the severe weather warnings.
"While heavy snowfall will undoubtedly have an effect on absence rates, it looks like the memories of February this year are still strong in peoples' minds and many are cautiously registering their absences today."
He advised employers to encourage staff to re-arrange unnecessary travel and postpone meetings where possible.
The multi-million pound cost identified by FirstCare was worked out using figures from the latest CBI Absence and Labour Turnover Survey, published in 2007.
Earlier this year the Chartered Institute of Personnel and Development praised companies that had put in place the technology and management practices to allow their people to work flexibly while the snow and ice thaws.