2005, Historical Saw The Highest Total Of Heavy Snowfall Days In The Uk

[blizzardmanuk]

Hi Guys,

In July 2005, I completed a PhD thesis into the spatial and temporal analysis of heavy snowfalls across Great Britain between the years 1861-1999. Since 1999, I have continued with this research to date.

Last year, 2005 saw 25 days of heavy snowfall, joint top with the year 1876 (the highest number of heavy snowfall days since 1861). The average number of heavy snowfall days per year based on the period 1861-1999 across the United Kingdom is 8.2 days. In recent years, other years have shown a significant high frequency of heavy snowfall days. The years 1999 and 1996 saw 14 heavy snowfall days, while 1995 sustained 13. The years 1993, 2001 and 2004 all saw 12 heavy snowfall days.

Officially, no definition of a heavy snowfall day exists (only an hourly heavy snowfall rate of >=4cm/hr is official recognised). Therefore the above statistics are based on the following criteria stated below. This was also the same criteria used within the PhD thesis.

13cm (5 inches) or more of snow must have fallen somewhere in lowland Great Britain in 24 hours (not accumulated depths) or was described a blizzard. The snow depth of 13cm was chosen as this reflected a good benchmark of cumulative snow depth based on the literature cited for snow disruption that interfered with normal life.

Why has this occurred in 2005? To be honest, I am unsure, however with reference to my thesis and similar major studies done in other countries such as Austria, Bulgaria, Canada and the U.S.A, heavy snowfalls (both in depth and frequency in days) have increased in recent decades. This may be down to a change in weather patterns and the increase of the temperatures of the air and the oceans due to the transfer of sensible and latent heat energy. Put in simpler terms, a warmer world will hold more moisture therefore the precipitation that has occurred in the winter season has been heavier and has still remained so far as snow. The results may also be down to better data collection and monitoring. Due to the small period sample of some of the meteorological data used, we cannot therefore be certain of some of the trends.

The heaviest snowfall depth recorded last year on a particular heavy snowfall day appears to be around 40-50cm in County Durham at the end of the heavy snowfall event of the 24-25 February 2005. This however, falls into insignificance in comparison to the four highest snow depths associated with other heavy snowfall events (HSEs) of the past 140 years as the table below shows.

15-16 February 1929 200cm Dartmoor

9-13 March 1891 150cm Dartmoor

18-19 January 1881 120cm Dartmoor

26-30 January 1940 120cm Sheffield, South Yorkshire

The largest 4 heavy snowfall events between 1861-1999 (by snow depth)

If you would like further information concerning historical heavy snowfalls across Great Britain, visit www.richardjwild.co.uk

Kind regards

Rich

Dr Richard J. Wild BSc (Hons) PhD FRMetS FRGS

Weather Services Commercial Manager - WeatherNet Ltd

Head of Heavy Snowfall and Blizzards Division, TORRO (Tornado and Storm Research Organisation)