Donegal County Council is warning motorists to assume that no road is ice-free with more bad weather on the way.
The council says gritting will take place on all designated routes tonight.
The warning comes after a number of minor accidents across the county.
The bad weather is set to continue through the weekend.
A status orange weather warning for snow and ice is in effect for counties Cavan, Monaghan, Donegal, Longford, Leitrim, Mayo and Sligo.
A second warning has been issued with Met Éireann saying that significant falls of snow are expected on Saturday night and into Sunday with accumulations of 4 to 8 cm or even greater in some parts.
Tonight will see a widespread frost and some icy patches with temperatures as low -3 degrees.
Tomorrow will be a very cold but bright day with sunny spells and some wintry showers, mainly in coastal areas. Temperatures will be no higher than 5 degrees.