The geyser shoots steam and water to heights of 75 feet (23 m) in an arch over the river, sometimes causing rainbows.

As is Old Faithful, Riverside is one of the most predictable geysers in the park, because it is not located near any other geysers that may disrupt the flow of underground water in the geyser's plumbing.

Riverside is unique in its way that eruptions seldom occur at the average interval for any given time.

For an hour or two before the eruption, water pours over the edge of the cone.

[2] The geyser was named by the Hayden Geological Survey of 1871.