Spencer Butte "Mirages"

Spencer Butte, Eugene City Parks & Recreation

January 14th, 2009 (1500 PST)

**Submit your photos/comments to romick1@comcast.net

* Aaron West
* Roy McCormick

Trip Report:

This was just a quick afternoon jaunt up 2,055' Spencer Butte just south of Eugene. Hikes up the Butte during winter temperature inversions can be fun since it gets you out of the valley fog and up into the sunshine. Once on top this time however I immediately noticed a strange "mirage" effect along the western and southern horizons. This "Superior Mirage" was caused by the strong temperature inversion that we were approximately 200' above. The boundary between cool (in this case ~ 35°F) air and warmer air (55°F on top of the butte) causes light to refract downward. The resulting lake like effects are actually images from over the horizon - most likely more foggy lowlands. I did not notice any mirages to the north or east of the butte. Winds on top of the butte were estimated at 10-15 knots from the NE while the wind below the inversion was calm. I would be interested in hearing from anyone who has experienced this effect.

http://en.wikipedia.org/wiki/Mirage - Here is a good article about mirages courtesy Wikipedia.

** Please note that the target photos are large .jpg files. Click on thumbnails for full- size images **

rm photos are not copywrited. Please feel free to save and use. (Right click... Save as...)




Aaron at the summit	4X Zoom looking west	No Zoom


Digital zoom looking west	View to the south	The mirages looked like lakes to the south


Several of the people at the top did not notice the effect until we pointed it out.	View west again	Enhanced Contrast

Other Adventures