Sunderland's gritting teams were not deployed overnight because heavy rain would have washed away road treatments, council chiefs have said.
Commuters faced long delays this morning as snow fell on the city's roads, with police closing the A690 at Houghton Cut after traffic was brought to a virtual standstill.
Many drivers took to social media to bemoan a lack of gritting on the roads.
But council chiefs said their teams had gritted the roads, it would have been washed away by the rain.
Michael Mordey, the councillor responsible for City Services, said: "Severe winter weather lasting days or weeks is not uncommon in our region and the city council has robust plans in place for winter maintenance.
"Following last night’s heavy rain, that would have washed away gritting treatments, gritters have been and are out treating main commuter and strategic routes.
"In line with the forecasts for falling temperatures, and the possibility of more snow and ice, there will be further treatments."
He added: "The council would remind all drivers of their responsibilities to be mindful of road conditions and to give way to gritters, especially in any rush-hour snow showers, and to drive safely."