March 19, 2006 Three types of ripples in water ice were observed
near Mt. Monadnock, New Hampshire on January 16, 2006. Ripples
may be defined as a banded pattern of wavelike disturbances.
They usually occur in fluids, but as seen here, they can occur
in solids as well. Leftmost: ripples formed by wind action on a
shallow puddle, subsequently frozen solid. Formation of ripples
by wind passing over a water surface is a classic example of an
emergent phenomenon: small disturbances in the surface self-
stabilize into a banded pattern when a current of one fluid
(wind) passes over the surface of another (water). What's
interesting here is that the ripples persisted during the
freezing process. Normally, wind ripples on water collapse and
re-form with each gust of wind. Center: The pattern of
horizontal bands seen here in a small iceflow have nothing to do
with the shape of the underlying surfaces, nor were they formed
by wind. Instead, the necessary current is supplied by meltwater
passing over the surface of the