Whirlwind Hits Lake Sammamish Over Memorial Solar Daytime Weekend Lifting Rafts Into The Air. Why Together With Hence Strong?
On Mon afternoon around v PM PDT, a whirlwind, besides known every bit a dust devil, struck the shore of Washington's Lake Sammamish, overturning tables together with lifting some rafts good into the air.
Here is an impressive video of the activity taken yesteryear Peter Barnes:
To navigate, hither is an areal map of the region, alongside a unopen inwards persuasion using imagery below that. The ruby marking shows the incident site.
Note that the whirlwind made landfall over the rattling northern business office of the lake...that may be important.
As shown on the video, the whirlwind was over H2O during the initial share together with and thence moved inland, where is looked similar a fairly classic dust devil.
But why did this vortex demo upwards in that location together with on this day?
First, some dust-devil 101. Dust devils are rotating columns associated alongside upward motion of a thermal of warm air. Favorable conditions include:
1. A relatively uniform apartment surface surface which is warmed yesteryear the sun
2. A large alter of temperature alongside tiptop (that promotes vertical instability together with ascent thermals)
3. Sunny or partly cloudy skies
4. Light winds inwards the region, since rigid winds tend to interrupt or distort thermal formation.
The location together with fourth dimension inwards interrogation had a lot going for it, if you lot similar a dust devil.
There was an extended flat, uniform expanse (in Marymoor Park) only to the northwest of the landfall site.... I suspect that is where the whirlwind was generated. Here is shot from the northern share of the apartment area. Dust devil territory for sure.
The regional winds were rattling low-cal inwards the area...with local observations around Lake Sammamish showing calm conditions (see surface conditions map at v PM Monday)
The twenty-four hours started out nearly clear together with became partly cloudy every bit the air became less stable--so in that location was Sun to warm the surface.
And in that location was a large alter inwards temperature alongside tiptop (known every bit a large lapse rate). Here is a time-height cross department at Seattle Tacoma Airport, showing temperatures (red lines) together with winds alongside tiptop for the 24 h menstruum ending eleven PM Monday. Between temperatures cooling aloft, piece they warmed at the surface, a large decrease of temperature alongside tiptop was apparent.
Looking at the observations at Marymoor Park, temperatures hitting the maximum (around 70F), only earlier the whirlwind formed.
So all the ingredients for a dust-devil were inwards place, alongside the expanse downwind of the apartment southern share of Marymoor Park existence a favorable location, a large alter inwards temperature alongside height, low-cal winds inwards the region, together with plenty Sun to warm the surface.
This whirlwind was scary for both human together with beast, terrifying some miserable dogs on the dock.
And the raft that was lofted high inwards the sky? After traveling hundreds of feet together with nigh fifty ft into the air, it came downwards on a lot several houses downwards the street. I bet that mystified the abode owner.
Here is an impressive video of the activity taken yesteryear Peter Barnes:
To navigate, hither is an areal map of the region, alongside a unopen inwards persuasion using imagery below that. The ruby marking shows the incident site.
Note that the whirlwind made landfall over the rattling northern business office of the lake...that may be important.
As shown on the video, the whirlwind was over H2O during the initial share together with and thence moved inland, where is looked similar a fairly classic dust devil.
But why did this vortex demo upwards in that location together with on this day?
First, some dust-devil 101. Dust devils are rotating columns associated alongside upward motion of a thermal of warm air. Favorable conditions include:
1. A relatively uniform apartment surface surface which is warmed yesteryear the sun
2. A large alter of temperature alongside tiptop (that promotes vertical instability together with ascent thermals)
3. Sunny or partly cloudy skies
4. Light winds inwards the region, since rigid winds tend to interrupt or distort thermal formation.
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| The whirlwind making landfall |
There was an extended flat, uniform expanse (in Marymoor Park) only to the northwest of the landfall site.... I suspect that is where the whirlwind was generated. Here is shot from the northern share of the apartment area. Dust devil territory for sure.
The regional winds were rattling low-cal inwards the area...with local observations around Lake Sammamish showing calm conditions (see surface conditions map at v PM Monday)
And in that location was a large alter inwards temperature alongside tiptop (known every bit a large lapse rate). Here is a time-height cross department at Seattle Tacoma Airport, showing temperatures (red lines) together with winds alongside tiptop for the 24 h menstruum ending eleven PM Monday. Between temperatures cooling aloft, piece they warmed at the surface, a large decrease of temperature alongside tiptop was apparent.
Looking at the observations at Marymoor Park, temperatures hitting the maximum (around 70F), only earlier the whirlwind formed.
So all the ingredients for a dust-devil were inwards place, alongside the expanse downwind of the apartment southern share of Marymoor Park existence a favorable location, a large alter inwards temperature alongside height, low-cal winds inwards the region, together with plenty Sun to warm the surface.
This whirlwind was scary for both human together with beast, terrifying some miserable dogs on the dock.
And the raft that was lofted high inwards the sky? After traveling hundreds of feet together with nigh fifty ft into the air, it came downwards on a lot several houses downwards the street. I bet that mystified the abode owner.
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