Proval bay was formed after a strong earthquake of 10 points on Richter's scale on the night of December 31st to January 1st 1862 (new styled calendar from 11-12th January 1862). About 200 square meters of soil - Tazheranskaya steppe together with 5 buryat campsites (ulus) went under water.
The northern part of today's Proval Bay was one of Baikal bays and was called Stariy Sor (old shore). Water started to appear from cracks in the ground. The inhabitants took only zhqt they really needed and left on boats. The earthquake was so strong that in Selenginsk the church bells were ringing by themselves and the crosses bent to the side. The tremors damaged the buildings more than 600 km away from the epicenter, and huge rock-collapses were registered at a distance of 400 meters away.
Almost 1,300 people from flooded campsites were left in cold January weather without a roof above their heads, house belongings and cattle. The lands of Tazheranskaya steppe which they inhabited for one and half centuries, houses and buildings, cattle and belongings went under Baikal waters.
Now Proval bay has an almost triangular shape. The side which is opened to Baikal waters stretches for about 22 km. The bay is separated from the lake by a chain of narrow and long islands, which are separated from each other by bays of different sizes. Proval starts from Oblom cape on the north-east and finishes near Dubinino village on the south-west. The depth in the bay grows gradually from west to east: from 0,5-1 to 3-3,5 meters. The deepest area is in the north-western corner of the bay near Oblom cape - about 5-6 meters.