On top, pit of ice in L'Obac Vell (range of L'Obac, Vacarisses, Vallès Occidental) as seen from the outside. Below, inside of the pit of ice in Rajadell valley (Manresa) lighted by a sunlight ray crossing through its collapsed dome. [photos Jordi Badia (top) and Florenci Vallès (down)]

The pits of ice or snow are big and deep, made of stone, underground constructions to keep ice and to supply it throughout the year. The ice pits worked during the centuries XVII, XVIII and XIX, in a relatively cold period that has been named the Little Ice Age. The ice pits were built in places with cold microclimate as north faces and lowlands. The origin of the ice was either the snow, like the two shafts in the mountain range of L'Obac, or the ice from ponds nearby, like the two shafts in Manresa, one near Rajadell stream, the other near Guardiola stream, and the pit in Calders. First ice was sawed to the right shape. Then, the ice blocks or the pressed snow were put into the pit where the coolness was maintained even in summer. The layers were separated by leaves or straw. The pit was brimful filled and closed. When needed, the pit was opened at night to pick up some ice that must be wrapped and carried quickly by horses. The ice was used to maintain food specifically fish, to cool drinks, to manufacture ice creams and also for medical purposes. Natural ice used to be a worth good in city life. Natural ice activity declined in the late nineteenth century, at the time when the artificial industry of ice began. However, the last ice pit stopped in 1932, in L'Avencó (Tagamanent, Vallès Oriental). The presence of ice pits at low altitude is consistent with the reports of colder temperature in seventeenth and eighteenth centuries. Certainly, the snow pit inthe range of L'Obac and the other ones in the district of Bages from the 1980's onwards couldn't operate several years. Some winters, the lack of snow or intense frost would've made the business of natural ice been ruinous. The ice pits in Catalonia, in places where nowadays ice is scarce in winter time, prove the global warming.

See graphs of evolution of number of days with temperatures below 0ºC and number of days with snowfall in Manresa, from 1930 to 2007. See also the snow on top of Montcau.