UK freezing rain - 23 to 24 January 1996
Freezing rain is fairly rare in the UK. When it does occur the consequences can be devastating. This case study looks at an occurrence which affected Wales, SW England and the Midlands in January 1996.
What is freezing rain?
Thankfully freezing rain is rare in the UK. It typically occurs at the end of a cold period when incoming milder air rises above the cold air. For freezing rain to form a layer of air above freezing needs to form above a layer of sub-zero air at the surface. The layer of air which is above freezing is often referred to as a 'warm nose'.
The image below shows the structure of the atmosphere required for a freezing rain event.
Precipitation will fall as snow initially, it will then melt (turning to rain and drizzle) as it falls through the milder air (warm nose) and then at the surface it will then re-freeze into drops of freezing rain.
When snow falls onto ground with a temperature blow freezing it gradually accumulates. When freezing rain comes into contact with a cold surface it glazes it in ice.
The meteorological situation
The map below shows the area which was affected in this particular event. High pressure over Northern and Eastern Europe had been controlling the weather with cold easterly winds affecting the UK. On the evening of the 23 January an area of low pressure moved slowly northwards across the south of England and gave outbreaks of rain. In some areas the rain turned to snow but in the areas marked on the map the snow turned to freezing rain with outbreaks through the night and intermittently through the 24 January.
The most significant impact of this freezing rain event was a spate of road accidents. In the Birmingham area a 50% increase in hospital admissions was reported. As well as car accidents, people slip on icy pavements and incidences of breaks, fractures and sprains increase.
The sight of motorists scraping their windscreens and applying deicer spray is a common one on many winter mornings. Can you imagine finding your car looking like one of the ones above on a winter morning?
Given that freezing rain coats whatever it touches ice, power and telephone lines are often affected. The increased weight due to the ice often downs the cables. In South Wales severe icing disrupted power supplies for some time.
At its most devastating freezing rain is capable of actually causing electricity pylons to buckle due to the shear weight, as shown in the photo above.