The Broomway traverses vast sand flats and mud flats that stretch almost unsloped for miles. When the tide goes out at Foulness, it goes out a great distance, revealing shires of sand packed hard enough to support the weight of a walker. When the tide comes back in, though, it comes fast – galloping over the sands quicker than a human can run.
Disorientation is a danger as well as inundation: in mist, rain or fog, it is easy to lose direction in such self-similar terrain, with shining sand extending in all directions. Nor are all of the surfaces that you encounter reliable: there is mud that can trap you and quicksand that can swallow you. But in good weather, following the right route, it can feel nothing more than a walk on a very large beach.