Snell's window

A Snell's window is the optical phenomenon resulting from the refraction of light moving through an air-water interface compressing the above-water view from 180 to about 96 degrees when looking up while submerged such as when scuba diving.

Snell's window
Trout, ripples, and a Snell's window in an Alaskan stream.
Alaska Biology Copper River Delta Ecology Snell's window South Central Alaska spring United States biological biosphere in situ living naturalworld organism underwater
Under a Snell's window
Chinook Salmon (Oncorhynchus tshawytscha) under a Snell's window
Actinopterygii Animal Biology Chinook Salmon Chordata Class Actinopterygii Ecology Infraclass Teleostei King Salmon Neopterygii Oncorhynchus tshawytscha Pacific salmon Phylum Chordata Salmonidae Salmoniformes Salmoninae Seacam underwater housing Snell's window Subclass Neopterygii Summer Teleost Teleostei Vertebrate biological biosphere chordate in situ living naturalworld nature organism underwater underwaterphoto wild
Foraging under a Snell's window
Coho Salmon (Oncorhynchus kisutch) parr and fry foraging under a Snell's window
Actinopterygii Animal Biology Chordata Class Actinopterygii Coho Salmon Ecology Infraclass Teleostei Neopterygii Oncorhynchus kisutch Pacific salmon Phylum Chordata Salmonidae Salmoniformes Salmoninae Seacam underwater housing Silver Salmon Snell's window Spring Subclass Neopterygii Teleost Teleostei Vertebrate biological biosphere chordate fry in situ living naturalworld nature organism smolt underwater underwaterphoto wild wild trout
Forested setting
A male Sockeye Salmon (Oncorhynchus nerka) holds a position high over a redd site as the female approaches from downstream in a forested setting as evidenced by the view through a Snell's window.
Actinopterygii Animal Biology Chordata Class Actinopterygii Ecology Infraclass Teleostei Neopterygii Oncorhynchus nerka Pacific salmon Phylum Chordata Red Salmon Reproductive behavior Salmonidae Salmoniformes Salmoninae Seacam underwater housing Snell's window Sockeye Salmon Subclass Neopterygii Teleost Teleostei Vertebrate biological biosphere chordate courtship in situ living naturalworld nature organism spawning behavior spawning pair underwater underwaterphoto wild
Spawning migration of maturing Sockeye Salmon
Spawning migration of maturing Sockeye Salmon (Oncorhynchus nerka) under a Snell's window. A drifting Willow leaf is a sign of the coming winter.
Actinopterygii Alaska Animal Biology Chordata Class Actinopterygii Ecology Infraclass Teleostei Neopterygii Oncorhynchus nerka Pacific salmon Phylum Chordata Red Salmon Salmonidae Salmoniformes Salmoninae Seacam underwater housing Snell's window Sockeye Salmon South Central Alaska Subclass Neopterygii Teleost Teleostei United States Vertebrate biological biosphere chordate in situ living naturalworld nature organism underwater underwaterphoto wild
Under a Snell's window
Under a Snell's window, a Pink Salmon (Oncorhynchus gorbuscha) guards her brood.
Actinopterygii Alaska Animal Biology Chordata Class Actinopterygii Ecology Humpback Salmon Infraclass Teleostei Neopterygii Oncorhynchus gorbuscha Pacific salmon Phylum Chordata Pink Salmon Salmonidae Salmoniformes Salmoninae Seacam underwater housing Snell's window South Central Alaska 2 Subclass Neopterygii Teleost Teleostei United States Vertebrate biological biosphere chordate in situ living naturalworld nature organism underwater underwaterphoto wild
Eulachon (hooligan) spawning run
Winterscape in April visible through the Snell's window above a Eulachon (hooligan) spawning run in Alaganik Slough, Copper River, Alaska; Thaleichthys pacificus; Osmeridae
Actinopterygii Alaska Animal Biology Chordata Class Actinopterygii Copper River Delta Ecology Eulachon Infraclass Teleostei Neopterygii Osmeridae Osmeriformes Phylum Chordata Seacam underwater housing Snell's window South Central Alaska Spring Subclass Neopterygii Teleost Teleostei Thaleichthys pacificus United States Vertebrate biological biosphere chordate in situ living marine life naturalworld nature organism underwater underwaterphoto wild