Sea Stack Cap Cloud

August 25, 2009


Photographer: John Wegmann
Summary Author and Editor: John Wegmann; Jim Foster

The photo above shows an odd cloud cloaking a sea stack in Olympic National Park, off of the Washington coast. Though cloud caps often are observed over mountain ranges, such as the volcanic peaks of the Cascade Range in the Pacific Northwest, in this case the conditions were just right for a cap to form near sea level. Air is cooled as it rises over an obstruction, sometimes even a small one. If the cooling is sufficient any moisture present will condense to form a cloud that caps the top of the obstruction. This process isn't too dissimilar from the fog that forms when your breath condenses on a chilly morning. As the parcel of air descends on the leeward (downwind) side of the obstruction, be it a mountain or a huge boulder, it warms and dries, dissipating the cloud. Photo taken on July 29, 2009