The tides can vary greatly, at roughly 14 metres (46 ft) between high and low water marks. Popularly nicknamed "St. Michael in peril of the sea" by medieval pilgrims making their way across the flats, the mount can still pose dangers for visitors who avoid the causeway and attempt the hazardous walk across the sands from the neighbouring coast.
Polderisation and occasional flooding have created salt marsh meadows that were found to be ideally suited to grazing sheep. The well-flavoured meat that results from the diet of the sheep in the pré salé (salt meadow) makes agneau de pré-salé (salt meadow lamb) a local specialty that may be found on the menus of restaurants that depend on income from the many visitors to the mount.