When breathing normally, air flows to the lungs through the mouth and/or nose. When sleeping, specially lying on ones back, the Soft Palate can relax and restricts the airflow. The Soft Palate vibrates, causing the 'snore'.
The Epiglottis may also restrict the airflow and may even cause brief periods when no breathing occurs (Sleep Apnoea) which can be harmful. Specially designed devices (eg Silensor) are designed to overcome the problem. These devices, once positioned and adjusted bring the lower soft tissue forward.
A "snore free" night is beneficial to both the snorer and his/her partner.
More information on Snoring