Ground snow load values in the UK are defined by a map in the NA to EN 1991-1-3, with values increasing with latitude and altitude. Sites in the Scottish Highlands, Pennines, and Welsh mountains have significantly higher ground snow loads than lowland sites in southern England. The site altitude is a critical correction factor: for every 100 m above sea level, the ground snow load increases by approximately 0.1 kN/m².
For rooftop solar PV, high snow zones result in larger imposed actions that combine with the PV dead load in Eurocode load combinations. On shallow-pitch or flat roofs with low-tilt arrays, snow accumulation behind panel rows can create concentrated loads higher than the uniform design snow load. Structural engineers assess these effects where the array layout creates potential for snow drift or accumulation.