The
19th of June had already provided very hot tempewratures (33.7C at Wyton, Beds) and some heavy storms in central England
and parts of Scotland. However as the afternoon wore on the storms continued to progress slowly NE and intensified further
– over North Yorkshire
by around 16Z some particularly violent storms brought torrential falls of rain. This caused some considerable disruption
to the area. The worst affected area being located to the south of the North York Moors national park with villages such as
Sutton-under-Whitestonecliff, Thirlby and the town of Helmsley
particularly badly affected by floodwaters.
Highest
rainfall totals reported during the evening from 16Z included 69.4mm at Hawmby (8 miles NW of Helmsley) – 60mm of which
fell in the first 30 minutes of the thunderstorm, and 40.4mm at Topcliffe. It is thought that despite these high rainfall
totals – this is likely not representative of the highest falls that occurred during the thunderstorms with rainfall
rates unprecedented in the region, at least in living memory.
The
shear volume of water had little time to sink into the ground as the deluge fell on the parched surfaces. This lead to very
fast runoff and a large “wall” of up to 6ft of water in places flowing through the Ryedale area and villages located
within the valley, the force enough to sweep furniture out through homes and remove livestock and vehicles with considerable
ease.
Some
villages were cut off for several hours – with 9 villagers airlifted to safety by RAF helicopters after being marooned
by the floodwaters. The bridge into the village of Hawnby was swept away and part of the A170 and B1257 from Chopgate to Helmsley were
closed after being washed away in landslides caused by the sudden downpour. The floodwaters in the areas worst affected were
also hampering efforts to restore power to around 6,000 homes.
Flooding
devastation in pictures:
http://news.bbc.co.uk/1/hi/in_pictures/4110186.stm
Further information
and pictures relating to this storm event will be added shortly.
Dave
Jamieson
Many thanks to Philip Eden and The Environment Agency for rainfall, temperature stats used
