Three big bombs were found after the storm near the Jamno Channel, in the town of Mielno, located in the West Pomeranian Voivodeship, the broadcaster reported.
The bombs, which are likely to have been made during World War II, were found by a tourist.
Police cordoned the site waiting for arrival of mine experts.
Poland was attacked by Nazi Germany in fall 1939, which marked the beginning of World War II. The campaign lasted for several weeks. The country was liberated by Soviet troops in 1944-1945.