Bus passengers have been warned to expect delays and alterations to services this morning because of heavy snow in some parts overnight.
First South Yorkshire said a combination of snow and ice has made it 'unsafe' to operate on some roads.
A company spokesman said: "After overnight snowfall, and some further accumulations this morning, particularly on local estate roads and on higher ground, coupled to freezing temperatures, there are some current impacts to local bus services.
"Most of these issues are the result of icy road surfaces making it unsafe to run on certain roads.
"Overnight gritting has taken place across the network, and the current list may change rapidly.
"Please note that the depot teams are checking routes now - most of the list below is the current list as carried over from late evening on Tuesday. As soon as more reports received, these will be shared.
"If you are travelling, please remember to take extra care on untreated surfaces such as pavements, wrap up warm and leave a little extra time for your journeys."
1a - Terminating Newfield Green.
3/3a - Not serving Jenkin Road or Newman Road at Wincobank - operating from Meadowhall to Firth Park via Page Hall.
8/8a - Not serving Basegreen due to ice. Operating direct along Birley Moor Road.
18/19 - Buses are not able to serve Heeley and Norton Lees due to road conditions. Operating direct via Chesterfield Road to Woodseats. Service 18 cannot serve Derbyshire Lane, Scarsdale Road and Hemsworth Road due to burst water main at the junction of Hemsworth Road and Warminster Road. Buses via Meadowhead, Bochum Parkway and Norton Lane.
20 - As above, plus weather conditions, buses are operating via Chesterfield Road, Meadowhead, Bochum Parkway and Norton Lane to Norton Water Tower roundabout.
24 - Due to road conditions, buses are operating Low Edges to Woodhouse only - not serving Bradway.
36 - Operating direct along Holywell Road avoiding Jenkin Road, Beacon Way and Wincobank Avenue.
38 - Staying on main roads only. Not serving Longley estate (Longley Hall Road) or Shirecliffe (Penrith Road).
41 - Using East Bank Road direct to/from Manor Top due to poor road adhesion on Eastern Avenue.
51 - Due to icy conditions on the Charnock estate, buses are terminating at Gleadless Townend. Not serving Lodge Moor - terminating at Crosspool.
52a - Not operating beyond Crookes (i.e. not serving Walkley Lane, Hillsborough or Wisewood). City to Woodhouse normal but monitoring road conditions around Beaver Hill and Badger estates due to reports of ice.
56 - Due to dfficulties with road conditions around Gleadless Valley along Leighton Road, and on Blackstock Road, buses terminating Newfield Green.
72 - Reports of icy conditions around Airport Business Park; remain on normal route with monitoring.
75/76 - Using Sicey Avenue direct; not serving Gregg House Road or Butterthwaite Road areas. Not using Woodseats Road due to conditons. Using Abbey Lane to divert - missing central Woodseats.
81 - Terminating at Malin Bridge due to road conditions in Stannington. Dore village icy but passable with care.
82 - Only operating Malin Bridge to Ecclesall - not serving Stannington or Millhouses due to road conditions.
83 - Operating via Ecclesall Road and Ringinglow Road. Not serving Greystones/High Storrs.
95 - Normal at present, but Bole Hill Road being monitored due to parked vehicles narrowing carriageway. If conditions deteriorate, diversion may be necessary.
97/98 - Poor conditions at Totley/Totley Brook, but remain normal here for now. Between Southey Green and Hillsborough, using Moonshine Lane and Herries Road.
114 - Missing Dale Road.
115 - Missing East Road.
120 - Due to deteriorating conditions in Fulwood, buses are terminating at Ranmoor.
271/272 - Due to deteriorating conditions at Fox House and beyond, buses are running only a skeletal service Sheffield to Ecclesall.
X1 - Roads in Maltby being monitored - normal at present.
X78 - Due to road conditions, buses are not serving South Street and Pitt Street at Holmes. Buses will operate via Meadowbank Road. Also, in the Doncaster area, buses are operating via A630 direct and not operating around Conisbrough.