© Bryan de Gruchy
St Peter, Jersey
Latitude: 49° 12' 48'' N
Longitude: 2° 11' 46'' W
18 January 2013 1307 (Local Time)
Image P/S code: P.11.4.6
Image I.D.: 4865
Glaze is a generally transparent, smooth and compact deposit of ice, formed by the freezing of supercooled rain or drizzle on objects whose temperature is generally below 0 °C.
In this picture, the twigs and thorns are completely encased in glaze, resembling a coat of clear ice. This followed approximately 4 hours of freezing rain. The supercooled raindrops fell through an elevated layer of air above the ground with a temperature greater than 0 °C and froze on impact with the twigs and other objects on the ground, where the surface temperature was below 0 °C.
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High pressure (1 025 hPa) over Scandinavia and low pressure (992 hPa) over the Adriatic maintained a cold feed of low-level air over north-western Europe to the western seaboard. The blocking pattern was delaying the slow eastward progress of a warm occluding front, lifting the warm air over the freezing cold continental air at the surface. Freezing rain was reported quite widely over north-western France that morning.
The midnight upper-air sounding for Bordeaux, France (WMO 07510) was taken in the same airstream as the location of the photograph. It displays the classic structure for producing freezing rain on the surface. A layer of warm air (up to 6 °C), caused by the slowly advancing front, rose above the cold, sub-freezing layer on the surface. The temperature at the photograph location in Jersey was between –1.0 °C and –0.5 °C for the preceding 9 hours.
(NB. Hour of day estimated)
In the picture glaze has formed on the bare branches of a young tree. The smooth deposit of ice has covered all parts which have been exposed to precipitation. The ice has developed pendulous formations on the underside of many of the horizontal branches.
After a period of cold easterly and northerly winds a weak cold front crossed the area.
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