Frozen Ripples on Birdbath

March 23, 2023



Photographer: Kate Farrell  
Summary Authors: Kate Farrell; Jim Foster

Shown above is a phenomenon I’d never seen before; ripples of water frozen in place. This photo was captured in Grand Junction, Colorado, on the morning of February 1, 2023, not long after a winter storm passed through. Strong winds ushered in cold air permitting temperatures to rapidly fall over a period of a few hours. The air temperature when the picture was snapped was about 13 F (-10 C). However, in the overnight hours the winds were sufficiently strong to initially prevent the water from freezing. But when freezing did begin, it happened so quickly that as you can see on my birdbath, ripples from the wind were frozen in time.

This is a classic example of an emergent phenomenon -- the current of one fluid (wind) passes over another (water). Although ripples tend to collapse and reform with each new wind gust, in this case, because of the rapidity of the cold air onset, they persisted throughout the freezing process.

Photo details: Photo taken on my iphone a little before 7:30 a.m. on February 1; the Sun was just rising.

Grand Junction, Colorado Coordinates: 39.0639, -108.5506

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Hoarfrost Flowers and Frozen Ripples