Observer Comments

14:14 Sun Oct 06, 2019

First Rime of the Season

Already in my first week and a half on the summit, I have been lucky enough to experience a wide range of exciting weather phenomena, which has given me a great taste of what is yet to come as fall transitions into winter. The most recent one of which included experiencing rime ice for the first time! This is something I had heard about (and seen lots of pictures of) but seeing it for yourself is quite amazing. When I stepped outside onto the observation deck in the morning, the sun was shining on the snow and ice that encased the summit and it made me feel as though I had stepped into a winter wonderland. I was finally able to see my first glimpse of rime ice!

When clouds envelope the summit and temperatures on the surface are below freezing, rime ice is able to form. When liquid water droplets come in contact with an object, they freeze and form this beautiful, feather-like type of ice that can build up along any surface (on rocks, the sides of buildings and along railings). Rime ice is typically opaque rather than clear due to the fact that the water droplets are freezing instantaneously upon contact (in spheres that trap little air bubbles). As those individual droplets collide with different surfaces, the ice builds up in the direction that the wind is coming from, so it makes for a very picturesque scene.


Rime ice covers the railings as the sun sets over the summit.

From preliminary data, it looks like the occurrence of rime ice this year (on October 5th) was the latest that the summit had experienced its first riming of the season. De-icing the instruments on the top of the tower became necessary as the temperature dropped to 15°F, which was the coldest of the season so far. I’m really glad to have gotten the chance to experience the first rime ice event!

Laura Kee, Summit Intern


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