Environment Canada has issued a rainfall warning for Pickering, Oshawa and Southern Durham region.
It said widespread total rainfall amounts of 20 to 40 millimetres are expected overnight and Saturday morning.
Rain, occasionally heavy at times, will continue into Saturday morning before becoming mixed with or changing over to patchy wet snow by Saturday morning.
The frozen ground has a reduced ability to absorb this rainfall, said Environment Canada.
It advised that storm drains should be clear of snow and ice to allow for proper drainage.
Heavy downpours can cause flash floods and water pooling on roads. If visibility is reduced while driving, slow down, watch for tail lights ahead and be prepared to stop. Localized flooding in low-lying areas is possible.
Localized Flooding
The Central Lake Ontario Conservation Authority (Cloca) said the local watershed has accumulated snow depths of some 15-25cm throughout the headwaters of creeks. The forecasted rainfall combined with frozen ground conditions, warm temperatures and associated snowmelt could result in increased runoff causing higher than normal water levels and flows in streams. In addition, melting ice and snow may contribute to ice jams and blockages, especially at bridges and culverts, which could lead to localized flooding.
The Central Lake Ontario Conservation Authority is asking all residents to stay away from all watercourses and structures such as bridges, culverts and dams. Elevated water levels, fast flowing water, and slippery conditions along stream banks continue to make these locations extremely dangerous. Please remind children of these dangers.
This Water Safety Statement will be in effect through Sunday January 26, or until further notice.
The Central Lake Ontario Conservation Authority will continue to monitor the conditions of the streams and will provide updates as required.