Not sure where exactly in Longton you are, but I'm about 100foot higher in elevation the Longton's town centre, and it's much less built up here, Norton's a very small council estate about half way up the Eastern side of Whitfield valley looking West (Smallthorn's on the Western side of the valley looking eastwards) and we are basically surrounded by greenbelt.
So not sure why it's vanishing so fast, I could understand if the snow was sublimating or something along those lines due to dry air, but humidity's at 80+% ¯\_(ツ)_/¯