User:Ddraigfawr/Welsh Snow Patches

Snow patches have been observed surviving in the mountains of Wales well into early or mid summer since the 17th century. Although they tend to survive longer in the Scottish Highlands (see Scottish snow patches), they are significant in that they are usually the last place in England and Wales to melt during the summer season.

Y Ffoes Ddyfn patch
The Y Ffoes Ddyfn ('The deep cut' in English) is by far the best documented patch in Wales. It lies in Carneddau range in Snowdonia, north Wales. The hollow lies unusually on the southern facing slopes of Carnedd Llewelyn an area known for its high snowfall at an altitude of nearly 3,000ft.

Despite its southerly aspect this patch is able to survive much longer in certain winters than many of higher altitude and latitude. It is believed this is primarilary due to the surrounding topology of the area. The patch draws on strong drift lines from the north, east and west - all of which are helped by the smooth hump-back topology of the Carneddau. The shape of the gully allows large drifts to collect under the right conditions. However, during spring seasons with much warm warm driven by a southerly wind the patch can undergo rapid thaw. Despite this factor most studies suggest under a colder than average spring season the patch could last until the following winter.