Those lucky to be looking over North Seattle on Tuesday afternoon were treated to a rare sight in typically benign-weather Seattle: a wall cloud.
KOMO photographer Stephen Ramaley shot this video from our north-facing balcony at our studio's home of Fisher Plaza, which is just across the street from the Space Needle.
The cloud formed as a thunderstorm rolled in off the Kitsap Peninsula just before 2 p.m.:
According to this great weather site at the University of Illinois, "Researchers have shown that wall clouds probably develop when some rain-cooled air is pulled upward, along with the more buoyant air, as the strengthening updraft attempts to replace ever-growing volumes of rising air. The rain-cooled air is very humid, and upon being lifted it quickly saturates to form the lowered cloud base."
Wall clouds are usually associated with severe weather and many times we'll see funnel clouds and/or tornadoes drop from their base. In this instance, the cloud fizzled before anything got going, but if you speed up the video, you can see some general rotation in the overall cloud structure.
Storm chasers in the Midwest are well versed with wall clouds, which tend to be way more impressive out there as their storms tend to be, well, way more impressive.
Check out this photo from Mike Hollingshead, who captured this incredible wall cloud near Grand Island Nebraska on May 10, 1995:
Hollingshead runs one of my favorite websites for storm photography. You can see more of his amazing work at extremeinstability.com
And to finish up on the storm that produced the wall cloud, in case you missed it, here is time lapse video of that storm as it rolled in from the Kitsap Peninsula and over Queen Anne Hill: