If, for example, a community is subject to an earthquake which destroys all of the houses and apartments, its members will have a sudden increased demand for new housing. Immediately after the disaster, the market for housing in the community will be temporarily out of equilibrium, suffering from an excess demand for houses and apartments (shortage). But if markets are free to operate (i.e., if prices are free to change), and given enough time, prices will increase causing (1) construction companies to build new houses in the short run and (2) new companies to enter the house and apartment-construction market in the longer run. This increase in production brings supply into balance with the new demand. The adjustment mechanism has cleared the shortage from the market and established a new equilibrium. A similar mechanism is believed to operate when there is a market surplus (glut), where prices fall until all the excess supply is sold off. An example of excess supply is Christmas decorations that are still in stores several days after Christmas; the stores that still have boxes of decorations view these products as "excess supply", so the prices are discounted until shoppers buy all the decorations (to keep them until next Christmas).