The United Lincolnshire Health Trust has cancelled all non-urgent outpatient clinics and operations today.
Conditions on the county's roads are so bad that emergency 4x4 vehicles are being used to help get key staff into work.
Urgent two week wait, radiotherapy, renal services and oncology clinics are going ahead as planned.
Mark Brassington, Chief Operating Officer with the ULHT, said that to help cope, outpatient staff and non-clinical staff were being redployed to wards and theatres.
Anyone who is unsure is asked to call the number on their appointment letter for advice.