The Waterfall paintings, which bridge the sensibilities of Conceptual art and Eastern philosophy, are contemplative investigations of space and chance. In this series, which the artist began in the 1980s and continues to produce today, Steir explores the technical possibilities available in paint, pouring and flinging it onto the canvas. This technique constituted an influential breakthrough in her style. To make the Waterfall paintings, Steir first applies oil pigment to canvases using thick brushes and slow, methodical strokes, sometimes working from a ladder. Her gestures are made with varying degrees of force, yielding marks that range from opaque and deliberate to thin, film-like traces. This method gives rise to shimmering mists and light washes of paint in some areas and powerful downward cascades in others. The Waterfall canvases appear dimensional and expansive due to their complex, multilayered palettes and dramatic colour combinations.

Synthesizing gesture with natural referent, Steir's Waterfalls demonstrate her ongoing investigation into the relationship between material and image. The line, the foundational creative mark, has a strong physical dimension in her practice. In the Waterfall canvases, Steir’s line is connected intentionally and reflexively to her movement. In this way, Steir questions the very possibility of abstraction: ‘It seems to me, when you put down a line, there is a line. How could that line be abstract? No matter what else it represents it is always still a line.’ Thus, in the Waterfall works, the line is a line, and the waterfall is a waterfall, rendered by actual cascades of paint.