MERCER ISLAND, Wash. — There was a brief, but notable wind event on the eastern shore of Mercer Island around 1:30 Tuesday afternoon.
Pictures sent to KIRO 7 by viewer Nicole Niederman shows some broken patio furniture and pottery as well as some pool toys thrown into Lake Washington.
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Meteorologist Morgan Palmer spoke to Niederman by phone and based on her account and the data, says this damage – which occurred in seconds and affected several homeowners – could have the result as the result of a “cold air funnel,” which has a similar structure to a waterspout but lacks the parent thunderstorm and mesocyclone of a full-strength tornado.
However, it might also have been a sudden event that occurred because of differences in daytime heating at the surface, combined with the topography of Mercer Island.
The National Weather Service in Seattle also didn’t see anything threatening in the skies around that time, and says without video of a funnel, precise identification is difficult.
Cold-air funnels can briefly form when an already horizontally-circulating “tube” of wind exists along a boundary. In this case, that boundary where wind was converging was probably the shore of Mercer Island.
The clouds in the pictures as well as satellite imagery are a tipoff that we had some “wannabe” showers were trying to get their act together nearby. But at this point, they were still just towering cumulus clouds.
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However, on a summer afternoon with ample daytime heating and rising air currects, those updrafts can be enough to stretch that spinning horizontal column of air and pull it skyward.
Then, if the circumstances are just right, the circulation can briefly accelerate and tighten, producing a short-lived wind event that can exceed 50 miles per hour. This can cause minor property damage and even injuries if struck by debris. In this case, there were no injuries and just some damage to outdoor furnishings and water toys, some of which were thrown into Lake Washington!
These swirling wind events usually last seconds to minutes, then are gone without a trace.
Cox Media Group
