With , Sylt is the fourth-largest
German island and the largest German island in the
North Sea. Sylt is located from off the mainland, to which it is connected by the
Hindenburgdamm. Southeast of Sylt are the islands of
Föhr and
Amrum, to the north lies the
Danish island of
Rømø. The island of Sylt extends for in a north–south direction. At its northern point at
Königshafen, it is only wide. Its greatest width, from the town of Westerland in the west to the eastern
Nössespitze near
Morsum, measures . On the western and northwestern shore, there is a sandy beach. To the east of Sylt, is the
Wadden Sea, which belongs to the
Schleswig-Holstein Wadden Sea National Park and mostly falls dry during low
tide. The island's shape has constantly shifted over time, a process which is still ongoing today. The northern and southern
spits of Sylt are exclusively made up of infertile sand deposits, while the central part with the municipalities of
Westerland,
Wenningstedt-Braderup and
Sylt-Ost consists of a
geestland core, which becomes apparent in the form of the Red Cliff of Wenningstedt. The geestland facing the Wadden Sea gradually turns into fertile
marshland around Sylt-Ost. Sylt has only been an island since the
Grote Mandrenke flood of 1362. The so-called
Uwe-Düne (Uwe Dune) is the island's highest elevation with
above sea level. The island in its current form has only existed for about 400 years. Like the mainland
geestland, it was formed of
moraines from the older
ice ages, thus being made up of a
till core, which is now apparent in the island's west and centre by the cliff, dunes and beach. This sandy core began to
erode as it was exposed to a strong current along the island's steep basement when the sea level rose 8000 years ago. During the process,
sediments were accumulated north and south of the island. The west coast, which was originally situated off today's shore, was thus gradually moved eastward, while at the same time the island began to extend to the north and south. After the ice ages, marshland began to form around this geestland core. In 1141, Sylt is recorded as an island, yet before the
Grote Mandrenke flood it belonged to a landscape cut by
tidal creeks and, at least during low tide, it could be reached on foot. In addition to the constant loss of land, the inhabitants during the
Little Ice Age were constrained by sand drift. Dunes shifting to the east threatened settlements and arable land and had to be stopped by the planting of
marram grass in the 18th century. Consequently, though, material breaking off the island was increasingly washed away and the island's extent continued to decrease. Records of the annual
land loss exist since 1870. According to them, Sylt lost an annual of land in the north and in the south from 1870 to 1951. From 1951 to 1984, the rate increased to respectively, while shorelines at the island's very edges at Hörnum and List are even more affected. Severe storm surges of the last decades have repeatedly endangered Sylt to the point of breaking in two, e.g. Hörnum was temporarily cut off from the island in 1962. Part of the island near Rantum which is only 500 metres (yards) wide is especially threatened. sand cushions successfully protected the historic house Kliffende on Sylt against storms, which strongly eroded the cliffs on the north and south sides of the sand cushion barrier (1999).
Measures of protection against the continuous erosion date back to the early 19th century when
groynes of wooden poles were constructed. Those were built at right angles into the sea from the coast line. Later they were replaced by metal and eventually by armoured concrete groynes. The constructions did not have the desired effect of stopping the erosion caused by crossways currents. "
Leeward erosion", i.e. erosion on the downwind side of the groynes prevented sustainable accumulation of sand. In the 1960s, breaking the power of the sea was attempted by installing
tetrapods along the groyne bases or by putting them into the sea like groynes. The four-armed structures, built in France and many tons in weight, were too heavy for Sylt's beaches and were equally unable to prevent erosion. Therefore, they were removed from the Hörnum west beach in 2005. Since the early 1970s, the only effective means so far has been flushing sand onto the shore.
Dredging vessels are used to pump a mixture of sand and water to a beach where it is spread by bulldozers. Thus storm floods would only erase the artificial accumulation of sand, while the shoreline proper remains intact and erosion is slowed down. This procedure incurs considerable costs. The required budget of an annual
€10 million is currently provided by federal German, Schleswig-Holstein state and EU funds. Since 1972, an estimated 35.5 million cubic metres (46.4 million cu. yd.) of sand have been flushed ashore and dumped on Sylt. The measures have so far cost more than €134 million in total, but according to scientific calculations they are sufficient to prevent further loss of land for at least three decades, so the benefits for the island's economic power and for the economically underdeveloped region in general would outweigh the costs. In the 1995 study
Klimafolgen für Mensch und Küste am Beispiel der Nordseeinsel Sylt (Climate impact for Man and Shores as seen on the North Sea island Sylt), it reads:
"Hätte Sylt nicht das Image einer attraktiven Ferieninsel, gäbe es den Küstenschutz in der bestehenden Form gewiss nicht" (If Sylt did not have the image of an attractive holiday island, coastal management in its current form would certainly not exist). The enforcement of a natural
reef off Sylt is being discussed as an alternative solution. A first experiment was conducted from 1996 to 2003. A sand drainage as being successfully used on Danish islands is not likely to work on Sylt owing to the underwater slope here. In parallel to the ongoing sand flushing, the deliberate demolition of groynes has begun amid great effort at certain beach sections where they were proven largely ineffective. This measure also terminated the presumably most famous groyne of Sylt,
Buhne 16 – the namesake of the local naturist beach. A number of experts, however, fears that Sylt will still have to face considerable losses of land until the mid 21st century. The continuous
global warming is thought to result in increasing storm activity, which would result in increased land loss and, as a first impact, might mean the end of property insurance. Measurements showed that, unlike in former times, the wave energy of the sea is no longer lost offshore, today it carries its destructive effects on to the beaches proper. This will result in an annual loss of sand of . The ample
heaths on the eastern side of the island provide habitats for many rare species of plants and animals which are adapted to the extreme conditions such as drought, warmth, wind. About 2,500 animal species and 150 species of plants have so far been recorded. 45% of those plants are on the
IUCN Red List. With several thousand individuals in the dune belt of Sylt, the
natterjack toad, endangered in Germany, has one of Germany's largest populations here. Their spawning places are wet dune slacks and shallow, short-lived pools. For a habitat they prefer sandy areas with vegetation, but the species has also been observed on the top of the Uwe Dune. The main threat for this species on Sylt is road traffic. The many
water birds and other coastal avians that have their hatching grounds on Sylt or use the island for resting on their
migrations constitute an
ornithological feature. There are two notable hatching areas on Sylt, the
Königshafen bay with the small island
Uthörn in the north and the Rantum basin in the southeast. Birds that hatch on Sylt include
black-headed gull,
Arctic tern,
pied avocet,
common redshank,
common gull,
oystercatcher,
northern lapwing,
common shelduck and
tufted duck. During the migration, Sylt is a resting spot for thousands of
brent geese and shelducks,
Eurasian wigeons and
common eiders, as well as
bar-tailed godwits,
red knots,
dunlins and
Eurasian golden plovers.
Ringed plover,
common snipe,
ruff and other species are less common visitors to the island. Regarding land
mammals, there is no significant difference from the neighbouring areas of mainland Nordfriesland. Primarily
European hare,
rabbit and
roe deer can be found and are also hunted as game on the island. When the island was connected to the mainland by the causeway,
red fox and
European badger also became common. West of Sylt a breeding area of
harbour porpoises is located. In addition, great numbers of
harbour seals and
grey seals, the latter being rather uncommon in German seas, can be found on sand banks off Sylt. Numerous associations and societies that care for the exploration and the protection of endangered animals and plants have branches on Sylt. Among them are the
Alfred-Wegener-Institute for Polar and Marine Research, Verein Jordsand and
Wadden Sea Conservation Station. Also the Federal Office for the Environment operates a research station in the dunes at Westerland.
Climate On Sylt, a
marine climate influenced by the
Gulf Stream is predominant. With an average of , winter months are slightly milder than on the mainland, summer months though, with a median of , are somewhat cooler, despite a longer sunshine period. The annual average sunshine period on Sylt is 4.4 hours per day. It is due to the low relief of the shoreline that Sylt had a total of 1,899 hours of sunshine in 2005, 180 hours above the German average. Clouds cannot accumulate as quickly and are generally scattered by the constant westerly or northwesterly winds. The annual mean temperature is . The annually averaged wind speed measures 6.7 m/s (15 mph), predominantly from western directions. The annual rainfall amounts to about 650 millimetres (25½"). Since 1937 weather data are collected at
Deutscher Wetterdienst's northernmost station on a dune near
List, which has meanwhile become automated. A number of commercial meteorological services like
Meteomedia AG operate stations in List too. Sylt features an
oceanic climate that is influenced by the
Gulf Stream. On average, the winter season is slightly warmer than in mainland Nordfriesland. The summer season, however, is cooler despite longer sunshine periods. The yearly average sunshine period is greater than 4.4 hours per day with some years exceeding the average sunshine for all of Germany. Also precipitation is lower than on the mainland. This is due to the low relief of Sylt's shoreline where clouds are not able to accumulate and rain off. ==Settlements==