Barograph

253/366

Today the atmospheric pressure dropped to the record low 928.0 hPa, which is lower than the previous lowest pressure recorded in 1994 at 930 hPa. Unusually, a weather system with a very deep low came over the Brunt Ice Shelf, just at the “right” time, while usually the weather systems move further north of Halley, over the Weddell Sea and the Southern Ocean.

In the picture is a Halley Barograph, with the marker fully resting on the base plate. Barely seen just in the bottom left corner of the image is the pressure line dropping sharply until it hit the limit. The actual pressure drop was 976 hPa to 935 hPa in 24 hours (yesterday) and then further down to 928 hPa in the following 5 hours, a total drop of 48 hPa in 29 hours!