Authorities from the Western Pomerania Lagoon Area national park have warned that the fracture has been widening, with smaller cracks developing off the main fault. It currently measures up to 10 centimetres wide.
“We are preparing for a catastrophe,” park official Frank Martitz told the Bild daily on Wednesday. He said the crack was not always visible, meaning those on the island should exercise extra caution when walking. Hiddensee is closed to car traffic.
And whilst he said that cracks in the upper surface of the earth are not an uncommon occurrence, Martitz explained that their two-kilometre fracture had been worsened by both high sea levels gnawing away at the Hiddensee's cliffs and heavy rainfall over the past six months.
The island, which measures just 3.7 kilometres at its widest point and 205 metres at its narrowest, is a popular destination for tourists due to its natural beauty. The limestone and chalky ground mean, however, that the cliffs can be prone to collapse.
Coastal paths in the Dornbush area and coastline areas have been deemed unsafe until further notice and cordoned off from the public.
A landslide on neighbouring Baltic island of Rügen in December 2011 has heightened concerns of a similar event further. A 10-year-old girl was buried alive under the several thousand cubic metres of chalky earth – similar to that which makes up Hiddensee. Her mother and older sister were also buried but managed to climb to freedom.