The main loads acting against the air-supported envelope are internal air pressure, wind, or weight from snow build-up. To compensate against wind force and snow load, the structure's inflation is adjusted accordingly. Modern structures have computer controlled mechanical systems that monitor dynamic loads and automatically compensate the inflation for it. The better the quality of the structure, the higher forces and weight it can endure. The best quality structures can withstand winds up to and snow weight to 40 pounds per square yard (21.7 kilograms per square meter).