Kvarken

Kvarken
Norra Kvarken, Merenkurkku
View over Kvarken from Svedjehamn, Björkö, Finland
Location	Finland, Sweden
Coordinates	63°30′N 21°00′E / 63.5°N 21°E / 63.5; 21
Type	strait
Part of	Gulf of Bothnia
Max. length	N-S: 60 km (37 mi)[1]
Max. width	E-W: 70 km (43 mi)[1]
Max. depth	25 m (82 ft)[1]
Salinity	4
Max. temperature	16 °C (61 °F)[1]
Min. temperature	0 °C (32 °F)[1]
Islands	6,550[1]

Kvarken (Swedish: Kvarken, Norra Kvarken (as opposed to South Kvarken); Finnish: Merenkurkku, lit. 'throat of the sea') is the narrow region of the Gulf of Bothnia separating the Bothnian Bay (the inner part of the gulf) from the Bothnian Sea. The distance from the Swedish mainland to the Finnish mainland is around 80 km (50 mi), while the distance between the outermost islands is only 25 km (16 mi). The water depth in the Kvarken region is only around 25 metres (82 ft). The region also has an unusual rate of land rising at almost 10 mm (0.39 inches) a year.^[1]

Several attempts to cross the strait swimming have been made, but cold water and currents have usually been insurmountable obstacles. The first successful crossing was carried out by Lennart Flygare, Pavio Grzelewski and Tore Klingberg, who on 24 July, 2018, swam from Valassaaret (Valsörarna) on the Finnish side to Holmöarna in Sweden. It took them 12 hours 2 minutes to cross the strait.^[2]