Menacing. That’s singularly the best word I can think of to describe a shelf cloud.

It was a little before 6:00 one evening in early September 2021 and hubby and I had made a rare decision to pick up dinner rather than cook. Swinging into the parking lot of a neighbourhood restaurant in Wasaga Beach we stepped out of the car and looked up. Right then and there we knew we had to head over to the beach.

Minutes later I stood on the beach staring up at it. Low, ominous, sharply defined, was a shelf cloud speeding across Georgian Bay. It literally spanned as far as I could see from the southwest to the northeast. The leading edge of an incoming thunderstorm the cloud was a spectacular visual reminder of the power of nature.

Shelf clouds are a type of arcus cloud. The Weather Network tells us that they form “as cold air from the storm slams into the ground and acts as a plow, pushing the warmer, less dense, air up and over itself. This moisture in the warm air condenses as it cools, creating the characteristic shelf-like look.”

Out over the bay the dark curtains hanging beneath it told me where the intense linear storm was beginning to drop sheets of rain. A couple of lightening flashes reminded people it was time to move off the beach. Armed with only my cell phone, I snapped a few pictures and a quick video, and jumped into the car as the raindrops began to fall.