Freezing Temperatures and Rime Ice

2011-09-15 17:23:34.000 – David Narkewicz,  Summit Intern

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Tonight is a very exciting night here at the Mount Washington Observatory. This evening temperatures are forecasted to drop below freezing. This will give a solid chance for objects on the summit to experience some rime ice buildup. There are two main characteristics that are needed for rime ice to occur, freezing temperatures and fog. When temperatures are below freezing, water droplets in fog rapidly freeze to the outer surface of objects. This build up usually take place on the side of the object facing the wind. Rime Ice coats objects in thin, white ice crystals. I have not experienced this phenomenon here on the summit yet as this is the first time since June temperatures are going to drop below freezing. Temperatures are looking to drop into the 20’s overnight and stay there throughout tomorrow night giving ample time for riming to occur.

As most know rime ice is a big topic of interest here on at the MWO. With the way it coats certain things, it is able to produce spectacular sights for pictures. It coats anything from clothes and hair to buildings and metal. This can be difficult for us at the MWO as it coats the outside instruments. These instruments need to be clear of rime ice or they will not operate and record data accurately. Cleaning these interments is usually one of the main duties for an intern. Tonight and tomorrow I will hopefully get to witness rime ice to better understand what I will be dealing with in the upcoming month as the average temperature will fall below freezing making rime ice more predominate.

David Narkewicz,  Summit Intern