TORONTO -- Winter storm warnings have been issued for much of southern Ontario as many communities in the region brace for a blast of snow.

Environment Canada is warning of hazardous winter conditions, with snow expected to begin Tuesday morning and intensify into the evening for many parts of the province's southern regions.

The weather agency says between 15 to 25 centimetres of snow is likely to accumulate in Toronto, Hamilton, London and Sarnia.

It says total snowfall amounts near 25 centimetres are likely for the Ottawa and Cornwall regions by Wednesday morning.

Strong winds are also expected to produce blowing snow and visibility is expected to be reduced to near zero at times.

Environment Canada is asking southern Ontario residents to consider postponing non-essential travel until conditions improve and warns that rapidly accumulating snow could make travel difficult in some locations.