The North and South beaches at Grand Bend were posted as unsafe for swimming Thursday.
Images captured by the beach cam on the Lambton Shores municipal website show strong waves with the north winds.
Lambton Public Health conducts regular sampling at Grand Bend, Pinery, Ipperwash, Highland Glen, Bright's Grove and Canatara Park.
We're reminded that following heavy rainfall, the water at area beaches may be temporarily polluted for up to 48 hours.
Lambton Public Health doesn't conduct sampling along the St. Clair River.