Shetland Snowfall

[Rollo]

On New Years day 1970 the temperature in Jan Mayern had fallen to -18c, the lowest so far of the winter, with a strong northerly developing in Shetland that afternoon the direct Arctic outbreak caused a sharp drop of temperature to freezing point giving snow flurries in the late evening. People woke to a snow cover, snow showers and some frozen pipes on 2nd January and the dat remained very cold giving Lerwick Observatory a maximum of only -2.8c. However as often happens with direct Arctic outbreaks, the first day or two gave the lowest temperatures of the cold spell.

The cold northerly airstream continued with snow and hail showers on the 3rd and 4th, and on Monday the 5th we awoke to a depth of snow which had brought road traffic almost to a standstill, and a snow-laden sky from which a few flakes were faling. A low edege of clear sky was visible to the ENE but this soon completely filled up. The snowfall intensity quickly increased during the morning and by the end of Monday 14" of snow had fallen at Lerwick Observatory in 24 hours, 13" of this in 12 hours. Luckily, the snow was slightly wet giving large flakes. and with only a moderate south-east to east wind there was little or no drifting, The 5th january 1-55 pm shipping forecast said that there was a polar low of 990 mb central pressure over Shetland, and this was the cause of the trouble.

This is the deepest snowfall I have seen in one day in Shetland over the past 30 years. However, no snow fell on the Tuesday and by that evening most of the roads had been cleared. Had there been severe drifting with this depth of snow, road clearing would have been an impossible task.

There was a slow thaw on Wednesday, Thursday and Friday, and a rapid one on Saturday 10th when conditions became very mild with mist and fog patches, which are rather uncommon for Shetland in January. Consequently, very little of the snow was left late in the day.

The long-range forecast predicted large fluctuations of temperature and how right it has been!