Because of the dredging work being done to construct a new elevated foot bridge to the famous tourist site the car park and causeway are being removed and the salt flats are no longer holding back the tide.
This meant that the Mont became an island again momentarily for the first time since 1879 last month. Now it will happen again on Thursday and Friday of this week.
The work currently being done will be complete in 2015 but between now and then the removal of the silt holding back the water means that when there are high tides it will be surrounded by the sea.
The Syndicat Mixte Baie du Mont Saint Michel, the committee which is overseeing the work, said that the Mont is set to be an island at 08.50 and 09.30 on Thursday 22 August and 09.30 and 21.47 on Friday 23 August.
â€˜The work undertaken so far means that the Mont will become an island for a short time when the high tides surround the rock,â€™ said a syndicate spokesman. He added that visitors should take care as the tides can be fast and dangerous. They are advised not to walk out into the bay.
As more and more silt that has built up over the last 130 years is removed, the Mont will become an island more often. It is estimated that in 10 years time it will be surrounded by the sea around 90 times a year.
The high and low tides over the next few days are also set to attract huge crowds to Normandy beaches to collect shellfish and they too are being urged to take care. The tides move out quickly but they also return quickly and people can get trapped.
People are also being reminded to respect the rules on the size and number of shellfish that can be taken. Rules are usually posted on signposts and at town halls. Conservationists are also urging people to replace rocks that they move to search for creatures.
After this weekend the next high tides are due on the 20 and 21st of September.