Batten Down the Hatches!

Advertisment
  • Synoptic chart at 18:00 on 11th January 2005, showing an intense storm moving north-eastwards close to north-western Scotland. Source wetterzentrale.de

    Satellite imagery showing the rapidly deepening and intense storm that brought gusts of 113mph to north-west Scotland last night. Source: MeteoGroup

  • Batten Down the Hatches!
    09.01.2015 16:41

    The north-west of Scotland is no stranger to stormy weather at this time of year. In fact, if a winter passed without any gales over this remote part of the UK, then it would be noted as extremely unusual! Over the next few days, several episodes of very strong winds are expected across the UK. But almost exactly 10 years ago, the weather was in a similarly foul mood when a very powerful Atlantic storm brought damage, destruction and, sadly, loss of life to this part of Scotland.

    The far north-eastern Atlantic, between Scotland and Iceland, can be regarded as a motorway for deep low pressure systems. The wintertime temperature contrast between the cold Arctic climate of Greenland and northern Canada, and the balmy north Atlantic ocean, often results in powerful jet streams generating here, blowing from west to east. A jet stream is a fairly narrow ribbon of high velocity winds, typically found at about 5 to 7 miles above the surface. When this temperature contrast is large and the jet stream is strong, then it can create powerful storms, with fierce wind speeds at the surface. These storms most often pass between Scotland and Iceland, hence why Glasgow is a considerably wetter and windier location in winter compared with London. 

    On 12th January 2005, an intense low pressure system, with a minimum central pressure of 944 millibars, tracked north-eastwards close to the Western Isles of Scotland and Shetland. It had its origins over south-eastern parts of the USA, picking up copious moisture from the sub-tropical Atlantic. As it interacted with a very strong jet stream over the north Atlantic and colder air from Greenland, it exploded into life and then crashed into north-west Scotland. Ferocious westerly winds pounded the Western Isles of Scotland during the night of January 11th, briefly reaching Hurricane Force (sustained winds of 74mph or more). Gusts of 115mph were recorded on the Isle of Lewis, with 101 mph at Stornoway, and 96mph over the Scottish mainland at Loch Glascarnoch. On the top of Aonoch Moor (approximately 4000 feet above sea level), a gust of 142mph was recorded. Thunderstorms and frequent downpours of rain and hail accompanied the squalls, making for a wild night of weather.

    The local communities on the Western Isles and coastal inlets of the north-west Highlands bore the brunt of the impact, with roads and railway lines blocked with fallen trees, water and power supplies lost and some buildings damaged. Ferry services and bridge closures meant it was almost impossible to travel in some locations. High tides coinciding with the stormy winds initiated some coastal flooding. A tragedy occurred between the islands of South Uist and Benbecula, when 5 members of the same family were killed as they tried to escape rising flood waters that threatened their home. As two cars attempted to cross a narrow causeway between the islands, they were overwhelmed by the rising tides and huge surging waves. 

    Keep an eye on the forecast over the next few days as several further episodes of stormy weather are likely, especially across the north and west. Snow showers will become widespread over Scotland on Saturday evening and night, bringing a return to winter here after very mild conditions today.

    By: Matthew Dobson